This document describes a patent for improvements in the production of the antibiotic griseofulvin under deep culture conditions. It finds that griseofulvin can be produced on a large scale through submerged aerobic culture of suitable organisms, such as Penicillium patulum, if the available nitrogen level in the culture medium is carefully controlled between 0.04-0.3% nitrogen. Optimum yields are obtained at nitrogen levels of 0.075-0.25%, with the specific optimum depending on factors like inoculum type and fermenter size.

1. * GB784618 (A)
Description: GB784618 (A) ? 1957-10-09
Improvements in or relating to the production the antibiotic griseofulvin
Description of GB784618 (A)
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j
PATENT SPECIFICATION
Inventors: ALAN RHODES, RODGER CROSSE, THOMAS PRIMROSE FERGUSON and
DEREK LAWRENCE FLETCHER 784,618 Date of fling Complete Specification
(under Section 3 ( 3) of the Patents
Act, 1949): March 14, 1956.
Application Date: March 28, 1955.
Application Date: March 28, 1955.
Complete Specification Published: Oct 9, 1957.
No 9012/55.
No 9013/55.
Index at acceptance: -Class 2 ( 3), AA 1 (B: CIB: CID 1), AA 2 C 2.
International Classification: C 12 d.
COMPLETE SPECIFICATION
Improvements in or relating to the Production of the Antibiotic
Griseofulvin A ERRATA SPECIFICATION No 784,618
Page 4, line 22, for "When" read "Where" Page 4, line 36, for
"quantitatively" read "qualitatively" Page 7, line 18, for "of" read
"or" Page 8, line 25, for "used" read "use" Page 11, line 101, for
"taken" read "take" Page 15, in the Table, line 10, for" 5 59 "read "
6.59 " Page 16, in the Table, line 1, for " 465 " read " 475 " Page
16, in the Table, line 6, for " 6 85 " read " 6.84 " Page 16, in the

2. Table, line 13, for " 8/07 " read " 8 07 " Page 16, in the' Table,
line 15, for " 8 13 " read " 9 13 " Page 18, line 65, for "source"
read "course" Page 20, line 99, for "is" read "in" Page 21, line 39,
for "asd" read "and" THE PATENT OFFICE, 29th October, 1957.
etd-a (t'cci k); and Mac Millan, Chem, & in August 25th 1951, p 719)
it appears di griseofulvin has been produced in surfa, cultures only
from iat least three species mould namely P griseofultum, P jcwczews A
and P putulum.
The antibiotic griseofulvin possesses valuab antifungal properties,
and inter alia is very sui I tu L ort-ne antibiotic contained in the
whole d broth In general, a griseofulvin producing at organism should
be used in the fermentation ce which produces, under deep culture
conditions, of at least 150 micrograms (,ug) of griseofulvin per ml,
of broth, it being understood that the culture is carried out under
the condile tions specified herein, and for a period t until mycelial
break-down just commences Ad 4 i i 1 I ?.PATENT SPECIFICATION
Inventors: ALAN RHODES, RODGER CROSSE, THOMAS PRIMROSE FERGUSON and
DEREK LAWRENCE FLETCHER 784618 Date of filing Complete Specification
(under Section 3 ( 3) of the Patents
Act, 1949): March 14, 1956.
Application Date: March 28, 1955.
Application Date: March 28, 1955.
Complete Specification Published: Oct 9, 1957.
No 9012/55.
No 9013155.
Index at acceptance:-Class 2 ( 3), AA 1 (B: CI 1 B: C 1 D 1), AA 2 C
2.
International Classification:-C 12 d.
COMPLETE SPECIFICATIC Improvements in or relating to the Produi
Griseofulvin We, GLAXO LABORATORIES LIMITED, a British Company of
Greenford, Middlesex, England, do hereby declare the invention, for
which we pray that a patent may be granted to us, and the method by
which it is to be performed, to be particularly described in and by
the following statement:-
The present invention is concerned with improvements in or relating to
antibiotics, and in particular relates to a process for the production
of griseofulvin under deep culture conditions.
Griseofulvin is a known antibiotic, which has been shown to possess
important antifungal properties Its structure was first established by
Grove et dat (Chem & Ind 17th March 1951, page 219) and the following
structure was assigned by them to the antibiotic:o.ca 3 O O %C 5 CH 3O
A li l = Uy Q OCH 5 The production and isolation of griseofulvin on a
large scale has hitherto proved difficult.
Thus from the literature (see Oxford et al, 7 Biocnhem XXXIII ( 2),

3. 240, ( 1939); Brian et al Trans Brit Mycot Soc 29, 173 ( 1946); Grove
et al, Nature 160, 574 ( 1947); Grove et al (toc cit); and Mac Millan,
Chem & Ind.
August 25th 1951, p 719) it appears that griseofulvin has been
produced in surface cultures only from at least three species of mould
namely P griseofulvum, P janczewskii and P pahtltm.
The antibiotic griseofulvin possesses valuable antifungal properties,
and inter alia is very suitthe Antibiotic able for use as an
antifungal agent, particularly in agriculture for use for example in
fruit and other sprays or as a seed dressing.
The use of an antibiotic, particularly on a large scale, such as for
agricultural purposes, requires that it can be cheaply produced in
large quantities The methods of producing griseofulvin hitherto
proposed have all involved the surface culture of various moulds, a
technique which is by no means suited to large scale production.
We have however now found that it is possible to obtain griseofulvin
on a large scale, and more conveniently than hitherto, by culturing
suitable organisms under submerged aerobic culture conditions, and by
paying careful attention to various factors governing the culture.
As is known, various species of the genus Penicillium produce
griseofulvin in differing quantities when grown on suitable media It
is difficult to specify exactly which species are suitable for the
production of griseofulvin by submerged fermentation, and indeed there
is considerable variation amongst stains of a particular species
Perhaps the simplest method of determining which strains may be used
for satisfactory deep fermentation is by carrying out trial
fermentations, according to, the method of this invention, and
selecting such strains as produce a reasonable level of the antibiotic
The antibiotic is found mainly in the mycelium, and in determining the
amount produced reference is made to Ithe amount of the antibiotic
contained in the whole broth In general, a griseofulvin producing
organism should be used in the fermentation which produces, under deep
culture conditions, at least 150 micrograms (jug) of griseofulvin per
ml, of broth, it being understood that the culture is carried out
under the conditions specified herein, and for a period until mycelial
break-down just commences A strain which produces at least 200
micrograms (j/g) per ml should desirably be used, and we prefer to use
a strain producing at least 500 micrograms (jug) per ml.
One strain that we have found to be particularly suitable for the
process according to the invention is that known as Penicillitumn
patulum &inier T 7 rom ( 4640,455) C M I.
39,809 lNRRL ( 989) as P urticce Bain (A)I 0 G Smith 1949 l This
strain and mutants thereof is at present preferred since it has been
found to give a high yield of griseofulvin under different submerged

4. culture conditions.
Moreover, this strain and mutants thereof has shown no substantial
tendency to produce dechlorogriseofulvin when grown under the
conditions specified herein, even applying tests sensitive to one
microgram/ml As is known, the dechoro compound has markedly less
antifungal activity than griseofulvin itself, and is of little value.
Other strains which have been tested and which have been found more or
less suitable are the following: Asymmetrica Fasciculata (P urticcae
series):Penicillium patulumn CMI 28,808 Bainier Coll-Thom ( 4640-454).
NCTC ( 1722) 1932-NRRL 994, ATCC 9260 Penicillium lrtice Bain, (Rg 8
g) (P griseoftivzrm) C B S Baarn Asymmentriaa Disaricata (P nigricans
series):
Pekiciittin nigrt'cancs (Bain) (Zaleski).
C.B S Baarn.
Penici 1 imil jarczewskii Zal.
C.M I 29,100 (Soil, Lakenheath Warren Suffolk 1947-J H Warcup B 25)
Penicillium albdum Sopp C M I.
40,219 Peniciliutnm, aciborskii Zal C M I.
40,568 (?T) Peniciliumn melinii Trnom C M I 40,216 It has been found
that in order to achieve the relatively high yields of griseofulvin
which are afforded by the present invention under deep culture
conditions, the fermentation should take place under certain either
essential or preferable conditions.
In general terms, the media to be used in the process according to
this invention should include a source of nitrogen, a source of carbon
anid energy, and nutrient salts Purely synthetic media (wherein, for
example, the nitrogen is present as sodium nitrate) may be used;
however, we prefer to use media wherein the nitrogen is provided by
complex organic materials, since as is known-such materials frequently
have the advantage of supplying growth factors often desirable to
support good growth of micro-organisms Suitable complex nitrogenous
materials include, for example, corn steep liquor (CSL) milk products
such as whey powder, buttermilk, liquid whey, cottonseed meal, oatmeal
and soya bean meal The choice of these materials wvill depend largely
on availability and cost, but is also influenced by other factors in
the fermentation technique employed, for example ease of control of p
H 70 The final choice must depend on the balance of advantage in any
given circumstances.
Good results can also be obtained by the use of two or more different
nitrogen sources together, as for example a mixture of corn steep 75
liquor and whey powder or liquid whey.
The source of carbon and energy is preferably a carbohydrate such as
lactose, glucose, sucrose or starch For economy, these may preferably
be supplied in impure forms as 80 waste products from other processes,

5. for example in the form of milk products media, molasses, or sulphite
waste liquor Fats may be used for this purpose, but carbohydrates are
preferable As with the nitrogen source, 85 the final choice will
depend on the balance of advantage in any given circumstances.
The nutrient salts which should be present particularly include
phosphates A source of chloride ions and magnesium ions is also pre 90
ferable, especially if the other nutrients used are deficient in
available chlorine and magnesium.
We have found that the most fundamentally important factor in
successfully carrying out 95 the invention is to control the level of
available nitrogen in the medium Although it has been found possible
to produce griseofulvin within a wide range of available nitrogen
levels in the medium, we have found that this 103 level markedly
influences the yield of griseofulvin, and for commercially
satisfactory yields must be carefully controlled at rather lower
levels than might be expected.
According to this invention therefore we 105 provide a process for the
production of griseofulvin under submerged aerobic conditions which
includes the step of culturing a griseofulvin-producing organism in a
culture nedium which will support the growth of said or 110 ganisi,
for the production of griseofulvin, said mrediutrincluding an
assimilable source of nitrogen at a level of O 04 % 5 to 0 30 % of N,
a scurce of carbon and energy, and nutrient salts.
For optimum results we find that the avail 115 able nitrogen level is
preferably between about 0.075 % and 0 25 %, We find that the optimum
nitrogen level shows some variation with type of inoculum and type of
fermenter For example, in 250 ml shake 120 flasks the nitrogen level
of the medium is optimal around 0 2 %, when a spore suspension is used
as inoculum, but around 0 10.15 % when a 5 % vegetative inoculum is
employed In 150-gal fermenters we have ob 125 tained very satisfactory
yields of griseofulvin with a nitrogen level of 0 2 % in the medium
and a vegetative inoculum This variation of the optimum nitrogen level
can be seen from the following table 130 784,618 TABLE A
Treatments 7 days 8 days 9 days 10 days 11 days Nitrogen Inocula
Carbohydrate Level p H Assay p H Assay p H Assay p H Assay p H Assay
Lactose 0 24 % 6 43 593 6 29 973 6 61 1080 7 07 1455 6 89 1230 , 0 17
% 6 40 664 6 20 902 6 45 952 6 71 1173 6 65 1318 , 0 10 % 6 45 840 6
31 1730 6 37 1564 6 68 1292 6 55 2625 Glucose 0 24 % 7 20 656 7 21 700
7 72 772 7 66 772 7 83 872 , 0 17 %o 7 20 532 7 20 810 7 51 861 7 66
933 7 68 1108 Veg,, 0 10 % 6 24 930 6 39 1220 6 88 726 7 06 884 6 83
1176 Inoc.
Sucrose 0 24 % 6 85 641 7 62 620 8 03 536 8 25 582 , 0 17 % 7 36 541 7
63 618 7 71 678 7 95 700 7 78 804 , 0 10 % 6 57 1070 6 51 1162 6 87
842 7 13 933 7 32 836 Starch 0 24 % 8 18 517 7 86 532 7 94 535 8 25

6. 602 8 47 470 , 0 17 % 7 97 397 7 63 535 7 77 702 8 02 604 8 33 612 , 0
10 % 6 86 1055 6 65 733 7 18 568 7 46 731 7 68 798 Lactose 0 24 % 6 63
302 6 19 308 6 18 287 6 58 332 7 03 570 , 0 17 % 6 71 339 6 26 301 6
69 333 7 01 400 7 28 682 , 0 10 % 6 60 259 6 09 300 6 23 342 6 38 386
6 41 360 Glucose 0 24 % 7 56 586 7 25 638 7 57 653 7 80 892 7 77 802 ,
0 17 % 7 39 764 7 05 730 7 51 572 7 73 602 7 73 725 Spores,, 0 10 % 6
44 640 6 78 604 7 76 659 7 08 596 Direct Sucrose 0 24 % 7 37 376 7 53
642 7 74 589 8 05 823 , 0 17 % 7 59 495 7 35 598 7 52 777 7 83 720 8
08 930 , 0 10 % 7 01 496 6 61 472 6 65 372 6 99 456 7 06 532 Starch 0
24 % 7 51 561 7 33 570 7 55 612 7 83 618 8 11 602 , 0 17 % 7 40 578 7
01 443 7 61 574 8 01 575 8 27 573 , 0 10 % 7 20 303 6 31 238 7 39 471
7 47 381 7 57 475 Veg Lactose 0 17 % 6 72 698 6 87 855 6 29 884 6 65
800 6 16 1016 Inoc (Chalk) 00 a O cl, The media employed to carry out
the fermentations whose results Jare tabulated above were as
follows:C.S L solids to give 0 1 %, 0 17 % lor 0 24 % N.
Lactose, Glucose, Sucrose or Starch 7 % K Hl PO 4 O 4 % KC 1 O 1 i%
Limestone 0 8 % (or in one case precipitated chalk) The following
factors are also important in the successful practice of the invention
to obtain the best results:(a) As stated above it is preferred that
the source of carbon and energy should be a carbohydrate The
carbohydrate level should preferably be rather higher than might be
expected.
The level of carbohydrate can be as low as 3.5,%, or even lower, but
we prefer that it should be above 51 % The upper limit is not
critical, but will not normally exceed about 12 % When the
carbohydrate is supplied in impure form, e g as molasses, it will of
course be understood that these percentages refer to the carbohydrate
content of ithe final medium, and will require correspondingly higher
perTABLE B centage additions of the impure carbohydratecontaining
material At stated above, sources of carbohydrate conventionally used
in fermentation procedures are all available for use in the present
process, including glucose, brown sugar and starch, but at present we
prefer to use lactose We find: however, that the beneficial effect of
lactose only becomes apparent when a vegetative inoculum is used, as
can also be seen quantitatively from ithe above Table A.
The beneficial results to be obtained from high levels of carbohydrate
can be seen quantitatively from the following Table B. Source and 7
days 8 days 9 days 10 days 11 days 12 days Quantity of Carbohydrate p
H Assay p H Assay p H Assay p H Assay p H Assay p H Assay 7 % Lactose
6 11 552 6 13 734 6,91 1300 6 41 1352 6 60 1135 3.5 % Lactose 6 74 510
6 84 636 6 51 772 6 65 604 7 28 534 7 79 600 7 % Glucose 7 07 613 7 02
775 7 85 778 7 45 754 7 64 837 7 85 862 3.5 % Glucose 7 89 473 7 91
471 8 47 500 8 43 470 8 40 514 8 71 498 7 % Sucrose 7 37 625 7 53 555
8 15 583 7 85 544 7 87 634 7 83 675 3.5 % Sucrose 8 10 388 8 08 448 8

7. 68 432 8 56 409 8 52 491 8 79 467 7 % Starch 7 08 503 7 59 684 7 92
606 7 57 813 7 62 826 8 09 917 3.5 % Starch 7 98 272 8 27 302 8 64 298
8 53 285 8 45 310 8 71 294 In the above table the results were
obtained using a vegetative inoculum in the following media:C.S L
solids to give 0 17 % N.
Lactose, Glucose, Sucrose and Starch 7 % or 3 5 % KHIPO 04 O% KCI 0 1
%/ Limestone 0 8 % (b) the p H of the medium is not critical, but
should preferably be adjusted to between 4.5 and 5 5 before the
fermentation commences During the course of ithe fermentation the p H
rises, and when complete is frequently of the order of 6 5 to 8
Griseofulvin itself is stable within the p H range of from 3 0 to 8 8.
In order to make any necessary initial adjustment of the p H, and in
order to buffer the fermentation, we have found it advantageous to add
to the medium between 0 4 and 1 2 % of phosphate and/or O 4-1 2 c% of
limestone or chalk It is at present preferred to employ 0 4 % to 0 8 %
of KHIPO, or K HPO, and 0.8 % of limestone It may be noted that these
substances also act as nutrient salts land that the phosphate in
particular has a very beneficial effect on the yield of griseofulvin
The 4.
00 o 00 on presence of limestone greatly diminishes pig the effects of
phosphate and of limestone we mentation of the broth In order to
illustrate now give the following two tables C and D.
TABLE C p H of Medium and Level of Limestone in Lactose-C S L Medium
Treatments 6 days 8 days 11 days Limestone Phosphate Level Level p H
Assay p H Assay p H Assay Nil Nil 6 20 197 6 32 362 7 20 452 ,,, 6 06
180 6 20 300 6 97 326 , O 4 % 5 84 248 6 03 289 6 84 655 ,,,, 5 84 325
6 00 250 6 73 624 , O O 8 % 5 84 270 6 07 380 6 64 515 ,,,, 5 84 280 6
00 442 0.4 % Nil 6 63 139 6 74 7 47 423 ,,,, 7 27 165 6 75 250 7 38
410 ,, 0 4 % 6 54 227 6 75 340 7 71 568 ,,,, 6 51 248 6 59 370 7 71
652 , 0 8 % 6 42 229 6 73 325 7 43 830 ,,, 6 49 227 6 81 325 7 58 798
0.8 % Nil 6 70 133 6 82 152 7 93 304 ,,, 6 89 133 7 12 200 8 08 312 ,
O 4 % 6 63 257 6 68 315 7 45 532 ,,, 6 62 253 6 58 312 7 48 631 , 0 8
% 6 61 248 6 81 315 7 59 672 ,,, 6 60 253 6 68 289 7 43 684 1.2 % Nil
6 78 152 7 03 252 7 97 307 ,,,, 6 93 148 7 31 277 7 99 381 ,, O 4 % 6
55 270 6 85 320 516 ,,,, 6 52 293 6 67 350 7 37 521 , O 8 % 6 61 238 6
76 292 7 37 611 ,,, 6 60 227 6 65 334 7 27 582 These results were
obtained using the lactose-C S L medium I described below, and from
them it will be seen that where the carbohydrate source is lactose the
ititres respond very favourably to the presence of phosphate, but only
slightly to limestone However, 784,618 784,618 undesirable brown
pigmentation occurred in the absence of the latter The next table
shows that using an otherwise similar medium, in which, however,
glucose replaced lactose, and with two different sources of phosphate
at a level of 0 4 % in each case, the beneficial effects of limestone

8. on the titre are much more marked Here again the presence of limestone
also reduced pigmentation.
TABLE D p H of Medium and Level of Limestone in Glucose -C S L Medium
Treatments 6 days 8 days 9 days Limestone Level Phosphate p H Assay p
H Assay p H Assay Nil KHIPO 4 6 05 475 6 76 535 7 i 1 570 ,,, 6 18 518
6 85 525 7 11 448 0.4 %,, 6 38 448 7 40 608 8 80 400 ,,, 6 36 485 8 39
626 8 06 620 0.8 %,, 6 85 473 7 44 740 8 88 633 ,,, 6 85 450 7 45 672
8 97 550 1.2 %, 6 88 525 7 30 584 8 13 592 ,, 6 84 535 7 41 760 8 02
522 Nil K 2 HPO, 6 42 480 7 24 670 7 83 512 ,, 6 40 450 7 27 658 7 83
510 0.4 %, 6 85 608 7 56 678 7 95 648 ,,, 6 94 606 7 51 708 8 08 681
0.8 %,, 7 28 625 7 50 735 8 07 634 ,,, 7 36 612 9 06 548 1.2 %, 7 21
602 7 58 740 9 13 736 ,,, '6 94 545 9 13 623 (c) The degree of
aeration should be good.
It appears in general that, within limits, the greater the aeration
the higher will be the yield of griseofulvin, and this is particularly
the case the higher the level of nitrogen in the medium It is however
impossible to quote precise values for the aeration, for as is well
known the degree of aeration depends not only on the actual rate of
air supply but also on the efficiency with which it is used, which in
turn depends on many other variables too numerous to detail, including
the size and shape of the fermentation vessels and the manner in which
ithe air is introduced.
The effect of increased aeration is illustrated in the following table
E, in which results are given for a series of fermentations carriel
out employing media in which the nitrogen level was in each case 0 15
% but in which the carbohydrate sources varied Volumes of mls, 60 mls
and 80 mls respectively of broth were in every case shaken in 250 ml
flasks It will be understood that the lower the broth volume the
greater was the aeration.
Except las regards the carbohydrate source the medium employed in each
case was similar to the C S L lactose medium I described below,
inoculated with 1 ml, 1 5 mls and 2 mls respectively of a submerged
spore suspension.
784,618 TABLE E
Treatments 6 days 7 days 8 days Broth Carbohydrate Volume p H Assay p
H Assay p H Assay mls 6 47 255 6 41 300 318 6.47 137 6 41 256 Lactose
60 mls 6 34 140 6 12 6 33 110 6.56 218 6 18 6 33 380 mls 6 67 187 6 56
270 6 41 208 7.03 158 6 41 218 6 47 205 mls 7 74 475 7 81 652 8 08 655
7.74 443 7 81 500 8 08 655 Brown Sugar 60 mls 7 75 441 7 57 515 7 59
606 7.61 395 7 74 505 7 84 593 mls 7 63 505 7 24 537 7 73 500 7.64 386
7 34 430 7 62 453 mls 7 47 585 7 57 675 932 7.47 554 7 57 727 Glucose
60 mls 7 52 562 7 50 615 7 70 708 7.52 546 mls 6 68 418 7 05 573 7 57
650 6.35 368 7 12 537 (d) The medium must contain a proportion of
available chlorine in order to avoid formation of dechloro

9. griseofulvin Provided that sufficient chlorine is present, the level
does not appear to be critical If complex organic materials are used
as the nitrogen source, these usually contain some proportion of
chlorine We have however found that it is usually convenient to ensure
satisfactory results by making additions of at least 0 1 % and
preferably of between O 1 and 0 25 % of suitable soluble chlorides and
we prefer at present to employ approximately O 1 % of KC 1.
(e) The inoculum employed can be either a spore suspension of a
freely-growing vegetative inoculum, but the latter is to be preferred.
Where a spore suspension is used to inoculate a 150 litre seed-stage
vessel we have found it satisfactory to employ 150 mls of suspension
having a count of approximately 18 x 100 spores per ml When well-grown
this vegetative inoculum is used at a level between 1 and % for
inoculation of the fermentation medium.
We now give, by way of illustration only, three examples of media
which have proved satisfactory for the production stage of the
process.
a) Medium for subme'rgetd fermentation (I) C.S L solids Lactose KC 1 K
Ho PO, Limestone Natural p H 2.85 % (= O 15 % N) 7.0 % 0.1 % 0.4 % 0.8
% b) Medium for submerged fermentation (II) Whey 5 73 8 % _ 3 5 %
lactose Lactose 3 5 % 60 1 % nitrogent KH 2 PO 4 0 4 % KC 1 0 1,% C.S
L solids 0 38 % (givingapprox.
Natural p H 0 035 % N) c) Medium for submerged fermentation (III) C.S
L solids 2 85 % ( 0 15 % N) Starch 7 O % K Cl 0 1 % K Hm PO 4
Limestone Natural p H 0.4 % 0.8 % is The temperature at which the
fermentation is effected is not apparently critical, but we at present
prefer to employ a temperature of approximately 250 C It is also often
desirable to /add an antifoam agent to the fermentation, such as white
mineral oil, conveniently in an amount in the medium of from 0 25 to 0
75 %.
It has been found that in order to bring about sporulation of the
griseofulvin-producing mould for the purpose of preparing a spore
suspension suitable for used as an inoculum, either for a development
or production stage, particularly in the case of the preferred strain
Peunicillium patiulum Bainier-Thom, it is not in general satisfactory
to employ the normal production medium We have however found that
spore suspensions can be produced in a submerged medium provided
certain requirements are met In particular it is desirable that the
total available nitrogen level of the media used for the production of
spore suspensions should be below 0 25 %, and preferably lie between 0
05 and 0 1 %, and also that good aeration should be maintained, the
latter factor being perhaps the more important The optimum values of
these factors vary slightly from strain to strain of the organism.
We have found that there is a marked interaction between the nitrogen

10. level and the aeration which is necessary, the lower the aeration the
lower being the level of nitrogen that is required As lan
illustration, we -have found that 600 mls of a medium in which whey is
used as the nitrogen source to give a nitrogen level of about 0 05 %,
and which includes suitable proportions of lactose, phosphate,
chloride and corn steep liquor, when strongly shaken in a 2 litre
flask at 250 C for six days gave prolific sporulation We will now
give, by way of illustration, an example of a medium that has been
found suitable for the sporulation stage of the process.
Medium for submerged sporulation of P patulum Bainier Thomn (IV) Whey
Powder approx 2 84 % to give 0 05 % 1 N 1.725 % lactose Lactose KH 2
PO, K I C.S L solids Natural p H 1.775 % 0.4 % 0.05 % 0.38 %, to give
approx.
0.04 % O N.
As previously mentioned, the spore suspension obtained from the
sporulation stage can either be used for direct inoculation of the
fermentation stage proper, or it can be subjected to development in
any suitable medium 70 to yield a vegetative inoculum for the
fermentation stage This latter course is at present preferred,
particularly where the carbohydrate source in the fermentation stage
is to be lactose; where glucose is used in the fermenta 75 tion stage
the advantage derived from a vegetative inoculum is not so apparent
The conditions governing the development stage of the process are in
general not unlike those in the final fermentation stage, and we have
found 80 that satisfactory results can be obtained with various
development media, including either of the media I or II described
above for the fermentation stage of the process.
We have found that griseofulvin produced 85 by the fermentation
remains to a major extent, e.g 90 %, in the mycelium itself rather
than passing into 'the broth, unless the fermentation is allowed to
proceed too far, in which case the mycelium breaks down and the griseo
90 fulvin may become distributed throughout the broth The extraction
of griseofulvin from the broth itself presents difficulties We
therefore prefer to take advantage of the retention of the
griseofulvin in the mycelium, and to stop the 95 fermentation before
break-down of the mycelium occurs to any substantial extent.
The extraction of the antibiotic can be carried out in any convenient
manner Methods for performing this extraction have been pre 100
viously proposed for surface cultures, and in general such methods are
suitable for use in the process of this invention.
We now give by way of example a general description of our preferred
methods of 105 extraction.
The mycelium is separated from the broth, preferably by filtration at
a p H which should be lower than 8 0 The filtrate, which contains

11. approximately 10 %,% of the griseofulvin pro 110 duced, is generally
then discarded, although if desired the antibiotic may be recovered
therefrom by separate extraction techniques.
The mycelial solid is extracted with an organic solvent, for example,
ethyl acetate, 115 n-butanol, amyl acetate or preferably butyl acetate
The extraction is conveniently carried 784,618 The air-flow was about
3 cubic feet per minute, (cf/m) for the first twentyfour hours and was
then increased gradually to 8 cf/m.
as growth developed and foaming subsided.
The temperature was 250 C with stirring at 350 revolutions per minute
(rpm) The seedstage was transferred to the fermentation medium at 28
hours.
Fermntation stage 450 litres of the following medium were used: CSL
solids, to give Nitrogen 0 2 % Lactose 7 % Limestone 0 8 i% KH 2 PO 4
0 4 % KC 1 0 1 % No p H adjustment Sterilised 20 mins at C.
The fermentation medium was inoculated with 10 % vegetative inoculum
from the seedstage fermenter.
Air-flow was maintained as near to 10 cf/m.
as possible for the first eight hours, and was thereafter
approximately 20 cf/m The temperature was 25 C and the stirring rate
was 350 rpm.
White mineral oil was used as antifoam as required.
Details of the fermentation were as follows:out by mixing the mycelium
and solvent together, preferably at an equal weight/volume.
for a period of approximately 15 minutes, and then separating them by
sedimentation and S Recantation This extraction procedure should
preferably be repeated two or more times The decanted solution is then
preferably clarified by centrifugation or by filtration, and
concentrated, preferably under vacuum so that the 'temperature does
not exceed 50 C The concentrat Ion is carried out to the fullest
extent practicable, and the concentrate is then allowed to cool to 20
C or thereabouts, and the solid filtered off If, as is commonly the
case, some oily liquid has been extracted from the mycelium at the
same time as the griseofulvin, any oil adhering to the solid is washed
off by mixing it with some suitable solvent, for example butyl
acetate, in equal weight/volume ratio and refiltering The washed solid
is dried, preferably under vacuum, for example over phosphorous
pentoxide at room temperature The crude griseofulvin thus obtained may
be purified by dissolving it in an organic solvent such as acetone,
filtering, and precipitation by the addition of water, in which
griseofulvin is not soluble to any extent.
This procedure can if necessary be repeated, and the product is then
dried yielding pure crystalline griseofulvin.
In order that the invention may be well understood, we shall now give,

12. by way of illustration only, an example of a small scale production
process for griseofulvin:Precparation of Spord suspension 600 mls.
of the following medium were autoclaved in a 2-litre conical
flask:Lf'actose 3 5 % Whey powder, to give t 'Nitrogen 0 05 % KH 2 PO,
0 4 % KCI 0 05 % C.S L solids 0 38 % (to give approx.
0.04 % N) The flask was inoculated with 'a suspension of spores from a
well sporulated Czapek-Dox agar culture of Perdicillium patulum
Bainier Thom ( 4640,455) C M I 39,809, and incubated on a shaker at 25
C for seven days By this time the culture had produced abundant
submerged spores.
Vegetativse seed-stage 150 litres of the following medium, contained
in a stirred fermenter, were inoculated with 150 mls of the suspension
of submerged spores containing approximately 18 x 106 spores/ml: Whey
powder} Lactose 3 5 % Lactose 5 to give Nitrogen O 11 % KH 2 PO 4 O 4
% K Ci 0 1 % C S L solids 0 38 % (to give approx 0 04 % N) No p H
adjustment Sterilised 20 minutes at C.
Log hrs.
0 56 114 138 162 Titre 530 910 1355 1675 The batch on solvent
extraction by the pro 100 cedure previously described gave 150 gins of
% pure griseofulvin.
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* GB784619 (A)
Description: GB784619 (A) ? 1957-10-09
Improvements in or relating to cold shaping of steel
Description of GB784619 (A)
PATENT SPECIFICATION
784619 Date of Application and filing Complete Specification May 26,

13. 1955.
No 15185/55.
Application made in United States of America on May 27, 1954.
Complete Specification Published Oct 9, 1957.
Index at Acceptance:-Classes 83 ( 2), A( 40: 123); and 83 ( 4), Q 1 (B
Q), Q 2 (A 3: A 5 AX: B: H), V 2, Z.
International Classification: -B 21 d B 23 d, p.
COMPLETE SPECIFICATION
Improvements in or relating to Cold Shaping of Steel We, AMERICAN
RADIATOR AND STANDARD SANITARY CORPORATION, a corporation organized
under the laws of the State of Delaware, United States of America, of
40, West 40th Street, City of New York, State of New York, United
States of America, (Assignees of BEN KAUL), do hereby declare the
invention, for which we pray that a patent may be granted to us, and
the method by which it is to be performed, to be particularly
described in and by the following statement: This invention relates to
cold shaping steel and has more particularly to do with the cold
working of a tubular steel article to very accurate dimensions and by
such cold working, providing one or more surfaces of the article with
an extremely smooth finish.
In many articles of manufacture, such as hydraulic or pneumatic
pistons and cylinders, it is necessary to form the work pieces with
very accurately dimensioned mating surfaces having an extremely smooth
finish in order to prevent leakage of fluid between these surfaces
when in use For example, in the case of accumulators it has heretofore
been the practice to finish the ir(er surface of the accumulator
cylinder by a honing operation in order to obtain the degree of
accuracy and smoothness required of such surfaces The operation of
honing such cylinders is not only costly and time consuming, but does
not always result in a surface having the dimensional accuracy and
smoothness desired.
The present invention contemplates a method and apparatus for forming
such smooth and accurately dimensioned surfaces on tubular work pieces
without the necessity of a honing operation, and it is accordingly an
object of the present invention to form such surfaces solely by cold
working operations.
According to one feature of the present invention a method of
producing elongate hollow articles which are provided with very
smooth, axially extending surfaces and which are extremely straight in
an axial direction comprises, cold extruding a hollow blank to
lPricsubstantially the same size and shape as required of the finished
hollow article and thereafter axially straightening said cold extru 50
ded blank and smoothing out the irregularities on the axially
extending surfaces thereof by a series of cold working operations

14. comprising relatively moving into contacting relation one surface of
the side wall of the blank and an 55 axially straight metal flowing
tool so that the blank assumes the axial alignment of the tool and
thereafter ironing out the opposite surface of the blank side wall by
applying pressure thereto in excess of the elastic limit of the 60
metal while the first surface is temporarily deformed by said tool to
thereby bring said wall into permanent axial alignment with said tool
and to permanently smooth out the irregularities in the surface
thereof 65 According to a further feature of the present invention a
method of producing elongate hollow articles which are provided with
very smooth, axially extending surfaces and which are extremely
straight in an axial direction 70 comprises, cold extruding a hollow
blank to substantially the same size and shape as required of the
finished hollow article and thereafter axially straightening said cold
extruded blank and smoothing out the irregularities 75 on the axially
extending surfaces thereof by a series of cold working operations
comprising inserting into said hollow article an axially straight,
smooth walled punch which is dimensioned to deform the blank into at
least tem 80 porary axial alignment with the punch and at the same
time elastically deform the irregularities on the inner surface of the
blank so as to conform to the smooth walls of the punch and while said
blank is so temporarily and 85 elastically deformed, relatively moving
the punch supported blank axially through an annular die dimensioned
to cold work the outer surface of the blank beyond the elastic limit
of the metal of the blank 90 Thus the invention contemplates an
arrrangement of a punch and a die arranged to successively operate on
a tubular work piece, first to flow metal in one direction to 784,619
smooth out any imperfections and roughness on the surfaces desired to
have the extremely smooth finish and then to flow the metal in the
wall of the work piece to produce a permanent deformation of such
metal so that the surface of the work piece originally worked upon is
substantially permanently set in the condition resulting from its
contact with the first die or punch with which it is engaged.
In practicing the present invention it is preferred to dimension the
first die or punch that is brought into contact with the work piece
only sufficiently different from the dimension of the work piece
worked upon to smooth out any irregularities or out-of-roundness on
the surface on which the extremely smooth finish is to be provided The
second punch or die is dimensioned to engage another surface of the
work piece while the work piece is still mounted on the first punch or
die to compress the wall of the work piece against the first punch or
die and thereby permanently iron out such irregularities or roughness
in the surface of the work piece.
It is appreciated that such work pieces cannot be heat treated

15. subsequent to the surface finishing operation if they are to maintain
their dimensional accuracy, and the present invention therefore also
contemplates the development of the hardness required in the finished
work piece solely by such cold working operations.
Thus, when necessary, the tubular article worked upon is, prior to the
surface finishing operation given a stress relief, for example at 900
to 950 F for a S A E 1010 or 1012 steel, so that the subsequent cold
working will raise the hardness to that required of the finished
article.
The invention wil be further described by way cf example with
reference to the accompanying drawings which illustrate one embodiment
of ithe invention and in which:Fig 1, 2, 3, 4 and 5 are somewhat
diagrammatic view S taken along the line x-x in Fig.
6 showing the successive operations of the apparatus employed in
accordance with the invention for producing the smooth surface
referred to on a cylindrical work piece.
Fig 6 is a view taken generally along the line 6-6 in Fig 1, Fig 7 is
a view taken along the line 7-7 in Fig 1, Fig 8 is an enlarged
fragmentary view showing in an exaggerated manner the operation of the
punch on the work piece, and Fig 9 is a view similar to Fig 8 and
showing the manner in which the die operates on the work piece.
The process of the present invention is adapted for finishing tubular
work pieces of most any type Such a work piece is shown generally at
10 The work piece 10 is in the form of a cylinder having a side wall
12 of substantially uniform thickness and a bottom wall 14 which may
be of irregular or regular shape The work piece 10 is preferably
formed of a low carbon or mild steel Such a work piece lends itself
admirably to being formed by a cold extrusion process such as
disclosed in our prior British Patents Nos 718,506 and 70 718,590
Normnally, when a tubular work piece such as show %n at 10 is formed
by a series of cold extrusion operations as disclosed in said
co-pending patents, the work piece possesses a substantially uniform
hardness throughout 75 wvhich is developed solely by cold working If
the hardness of the blank 10 is at or substantially at the hardness
required of the finished article, then the blank is subject to a
stress relief treatment to reduce the hardness a 80 desired amount so
that the subsequent cold working operations again raise the hardness
of the article to that desired of the finished work piece In our
process, the extent of hardening by cold working the blank to produce
the 85 finished articles can be calculated or estimated; and
therefore, if the blank is not of the correct pre-hardness,, it is a
simple matter to stress relieve the blank to an extent necessary to
obtain the hardness desired in the subsequent 90 cold vworking The
temperature at which the blank is stress relieved should be maintained

16. within a prescribed range depending on the carbon content of the steel
and its hardness created by prior cold working operations For 95
example, in the case of having cold worked S.A E 1010 or 1012 steel to
a hardness of 95 Rockwell B, than a stress relief of 925 F.
+ 25 is preferred so that the hardness can be reduced to 85 to 90
Rockwvell B so that the 100 final hardness after working the metal as
set forth herein is raised to 98 to 100 Rockwell B. The higher the
ultimate strength produced by cold working, the higher the yield
strength, the less the elongation, and the higher 105 the spring back
If the stress relief anneal is too low, the elastic limit may be
exceeded during subsequent cold working causing cracking and galling
If the strees relief is to high, the elongation is greater and
although the metal 110 stays where it has been displaced, it would not
have the required final strength or hardness.
A hardness of 90 Rockwell B is the critical point above which
subsequent cold working may cause trouble The thickness of the wall
115 also limits the amounts of cold working A thin wall will stand
less cold working than a thick wall to obtain the same hardness and
ultimate strength.
The blank 10 is initially formed slightly 120 less than the nominal
dimensions required of the finished work piece The blank, whether it
be formed by cold extrusion, drawing, etc, necessarily has at least a
slight degree of out-of-roundness depending upon the length and 125
the diameter of the blank In addition, there will be slight
irregularities on the inner and outer surfaces of the blank walls as
shown at 11 and 13 in Figs 8 and 9.
Assuming that the blank 10 is of a hard 130 size of the punch with
respect to the inner diameter of the blank will depend upon several
factors; primarily, upon the diameter of the blank and the
out-of-roundness of the blank.
The extent of oversize of the punch is pre 70 ferably just sufficient
to smooth out the inperfections and roughness on the inner surface of
the blank wall and to eliminate any out-ofroundness of the blank.
Considering for the moment only the opera 75 tion of the punch 24
shown at the left of Fig.
1, when the punch assembly is moved downwardly to the position shown
in Fig 2, the punch will engage within the bore of the blank seated in
ring 30 and will slightly expand Su the blank as it moves
progressively downwardly into the blank.
Referring now to Fig 8 wherein the out-ofroundness of the surface
irregularities on the blank 10 are shown in a somewhat exagger 85 ated
form it will be observed that as the punch 24 travels downwardly into
blank 10, it smooths out the irregularities 11 on the inner surface of
the blank and displaces the metal in such irregularities in a

17. direction outwardly 90 Thus, when the punch has progressed down-wardly
to the position shown in Fig 3, the inner surface of blank wall 12 has
been smoothed out and the blank tightly grips the punch The extent to
which the blank is 95 expanded by introducing the punch 24 therein is
preferably such that if the blank is removed from the punch at this
point, the wall of the blank will spring back to its original
condition In other words during the step of 100 inserting the punch
into the blank, the blank wall is subjected to a stress preferably
below the elastic limit of the steel.
After the punch has been Sully inserted in the blank 10, the punch
assembly is raised, 105 the blank clinging to the punch, and the ram
plate is rotated 90 to bring the punch with the blank thereon into a
position in vertical alignment with the die ring 40 in the adjacent
die holder 34 A second pair of blanks are 110 then positioned in the
two locating rings 30 from which blanks have just been lifted by the
punch The punch assembly is then caused to move downwardly again as
shown in Fig.
2 The blank 10 which had previously grippcd 115 the punch 24 is
thereby driven downwardly through the die ring 40 Die ring 40 has a
diameter less than the outer diameter of the expanded blank 10 and
preferably less than the outer diameter of the blank prior to its
expan 120 sion by the punch 24 Thus, the wall of the blank is squeezed
laterally by the die ring 40 and is caused to flow slightly axially
The cold working of the outer surface of the blank wall in this manner
irons out the irregularities on 125 the outer surface of the blank and
compresses the inner surface of the blank wall against the surface of
the punch thereby welieving the stresses set up by the elastic
deformation of the blank wall by the punch and more or less 130 ness
such that subsequent cold working thereof will produce the desired
hardness in the finished article, the first step of the present
process is to subject the blank to a pickling operation to remove any
foreign particles in the inner or outer surface of the blank If a
stress relief of the blank is required, such stress relief of course
precedes the pickling operation Any conventional acid pickling
operation may be employed Thereafter, the blank is washed free of acid
and given a conventional phosphate treatment After being coated with a
lubricant, the blank is ready for sizing and finishing in accordance
with the present invention.
Referring now to Fig 1, there is illustrated in a general way the
apparatus employed for producing such sizing and surface finishing
operation The apparatus illustrated is designed to be mounted in a
press not shown and includes a punch shoe 16 on which is rotatably
supported a ram plate 18 Ram plate 18 is rotatably supported on shoe
16 by means of a central bearing assembly 20 and a series of gibs 22

18. Four punches 24 spaced 90 apart are mounted on ram plate 18 by means
of punch holders 26 Punches 24 are all the same size as described more
fully hereinafter The punch assembly mounted on die shoe 16 is
arranged to move vertically toward and away from a die assembly
mounted on the press by means of a lower die shoe 28 It will be
appreciated, of course, that a punch and die assembly constructed for
relative movement in a horizontal plane may be employed if desired.
It will also be appreciated that although four punches are shown, a
greater or lesser number may be employed.
On die shoe 28, there is arranged a pair of diametrically spaced
locating rings 30 provided with a cavity 32 shaped to receive the
lower end of blank 10 Die rings 30 are in juxtaposed relation to a
pair of diametrically opposed punches 24 on the upper shoe 16.
There is also arranged on die shoe 28 a pair of diametrically opposed
upright die supports 34 which are provided with an axial openng 36
therethrough Die shoe 28 is also provided with openings 38 which
register with the openings 36 in supports 34 A die ring 40 is mounted
on each support 34 by means of the die holder 42 and a clamping ring
44 The assembly also includes conventional stripper heads 46 Mechanism
not shown is also provided for rotatably indexing ram plate 18 to
successively position the punches 24 first over a locating ring 30 and
then over the adjacently positioned die support 34.
Punch 24 is very accurately machined so that its shank is formed by a
truly cylindrical surface of very accurate diameter The diameter of
punch 24 is only slightly larger than the inner diameter of blank 10
For example, the diameter of punch 24 may be on the order of 005 " to
025 " greater than nominal inner diameter of the blank 10 The degree
of over784,619 784,619 permanently setting or fixing the inner surface
of the blank in the condition resulting from its contact with the
cylindrical wall of the punch.
The extent of cold working of the blank wall as the blank is driven
through the die ring 40 causes a permanent deformation of the metal.
Therefore, when the punch assembly has moved downwaardly to a position
such as shown in Fig 3, the imperfections, roughness and
irregularities on the inner and outer surfaces of the blank wall have
been permanently ironed out and the stresses in the blank wall due to
expansion have been substantially reduced so that the blank is readily
stripped from the punch by the stripper leaves 46 when the punch
assembly is elevated as shown in Figs 4 and 5.
When stripped from the punch as shown in Fig 5, the work piece shrinks
only very slightly but substantially uniformly so that the diameter of
the final article generally designated 48 w-ill not vary from top to
bottom more than 002 " in a cylinder 42 " long and having a diamter of
4 " By determining the extent which the work piece shrinks after being

19. stripped from the punch, the size of the punch and the die can be
readily controlled to produce a very accurately sized work piece For
example, by mieans of the present invention, a tolerance of + 001 "
has been held on a work piece having a diameter of 5 " and work pieces
of about 1 " or less in diameter may be held within a tolerance of +
0005 ".
In order to illustrate typical relationships between the diameters of
the punch and die in relation to the blank before and after being
subjected to the operations illustrated in Figs.
1 through 5, reference may be had to the table set forth below wherein
such dimensionsfor four work pieces of different diameters are
gilvenil:Blank as extruded Punch Die Finished articie 0 D I D Dia Dia
O D I D.
A 5 398 " 4 726 " 4 758 " 5 355 " 5 370 " 4 750 " to to 4.745 " 4 752
" B 910 " 746 " 751 " 906 " 907 " 750 " to to 912 " 7515 " C 2 760 " 2
002 " 2 0255 " 2 743 " 2 752 " 2 020 " D 3 524 " 2 498 " 2 521 " 3 490
" 3 501 " 2 519 " to 3.502 " It will be observed that since the punch
24 slightly expands the blank by slidably engaging the inner surface
of the blank wall, a burnishing action is produced This burnishing
action coupled with the burnishing and ironing out of the
irregularities on the outer surface of the blank wall by driving the
expanded blank while on the punch through the die ring 40 produces an
extremely smooth finish on the inner and outer surface of the blank
wall Articles have been produced in this manner having a surface the
smoothness of which eliminates any necessity for honing Work pieces
have been consistently produced having a smoothness of about 30 RMS
With reference to cylinders, the present invention is especially
suited since any working marks that are produced lie in an axial
direction rather than a circular direction as is the case with honing.
In carrying out the present invention as described herein, it is
preferred to reduce the cross sectional area of the blank to the
extent of about 4 to 5 % The hardness and physical properties of the
blank are preferably increased up to about 20 %, depending upon the
physical properties of the blanks as compared with the physical
properties desired of the finished work piece.
In the arrangement illustrated and described herein an extremely
smooth finish is formed 85 on the inside and on the outside of the
finished article There has been some argument as to which of the two
surfaces is the smoothest and tests seem to indicate that the outer
surface is ihe smoother Regardless of on e,hich surface 90 the
smoother finish is obtained, it will be appreciated that the sequence
of operations may also Dbe reversed For example, the oversized blank
may be first driven into a die having an undersized cavity in which
the blank 95 is adapted to be received and thereafter an oversized

20. punch driven into the blank In this method of operation, the die and
the punch would be dimensioned in relation to the blank so that the
metal is stressed to an extent pre 100 ferably less than its elastic
limit when the blank is driven into the die and to an extent in excess
of its elastic limit when the punch is driven into the blank In using
the method of the present invention, past experience has 105 shown
that when the dimensional difference betveen the work piece and the
tool is too great, galling of the surface being worked upon results.
It will also be appreciated that although the 110 invention is
described with reference to an article of circular cross section,
articles having 784,619 a cross section other than circular may also
be worked in accordance with the method and the apparatus of the
present invention It is merely necessary to provide punches and dies
of the same shape as the article to be worked upon Likewise, the
invention may be utilized for forming a smooth finish on an article
having tapered side walls rather than straight side walls as
illustrated.
Thus it will be seen that we have provided a novel punch and die
arrangement and a novel and efficacious method of cold working a
tubular blank to produce a finished tubular article having a cross
section maintained within a very narrow dimensional tolerance and
having a surface which is exceedingly smooth.
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* GB784620 (A)
Description: GB784620 (A) ? 1957-10-09
Manufacture of aliphatic chloroepoxides
Description of GB784620 (A)
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21. [75][(1)__Select language]
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The EPO does not accept any responsibility for the accuracy of data
and information originating from other authorities than the EPO; in
particular, the EPO does not guarantee that they are complete,
up-to-date or fit for specific purposes.
PATENT SPECIFICATION
Date of Application and filing Complete Specification: June 8, 19
No 16537/55.
Application made in United States of America on June 28, 1954.
Complete Specification Published: Oct 9, 1957.
Index at acceptance:-Class 2 ( 3), C 1 G( 1 A 2: IE; 513; 6 A 1; 6
811), C 3 A 15.
International Classification:-C 07 c, d.
COMPLETE SPECIFICATION
Manufacture of Aliphatic Chloroepoxides We, UNION CARBIDE CORPORATION
(formerly Union Carbide and Carbon Corporation), of 30, East 42nd
Street, New York, State of New York, United States of America, a
Corporation organised under the laws of the State of New York, United
States of America, (assignee of BENJAMIN PHILLIPS jointly with PAUL
SPENCER STARCHER), doi hereby declare the invention, for which we pray
that a patent may be granted to us, and the method by which it is to
be performed, to be particularly described in and by the following
statement:-
This invention relates to a process for the production of aliphatic
chloroepoxides,, and more particularly to a process for the productibn
of aliphatic chloroepoxides by the reaction of an aliphatic
chloroalkene with peracetic acid or perpropionic acid.
According to the present invention a process is provided for the
production of aliphatic clo roepoxides which comprises; reacting an
allylic chlorohydrocarbon having the group:
I I l -C =C-C-C 1 I i.
with peracetic or perpropionic acid substantially free from hydrogen
peroxide, water, mineral acids and salts, ro form the corresponding
dhloroepoxy compoaund.
Examples of starting materials to which the process; of this invention
is applicable are those aliphatic chloroalkenes containing from three
to ten carbon atomsl in the skeletal chain which may be represented by
the general formnula:
R 2,3 R 4 RI -C-C-C-Ct R 5 ii.
wherein R,, R, R,, R, arnd R, represent hydrogen, allo or chloroalkyl
radicals.

22. As may be readily observed from the general formula ii set forth
aboave, these starting materials, that is the aliphatic chloroalkenes,
possess in common, at least one chlorine atom in the allyliie position
and no, chlorine atoms joined directly to either of the olefinic
carbon atoms.
The tern "allylic position" as, used herein is intended to refer to
the position of the chlorine atoms with respect to the position of the
clefinic double bond of the basic carbon chain Expressed in terms; of
a molecular illustration, the characteristics; grouping referred to as
the allylie position can, be represented by the structure:
I l I 1 -C = C-C-Cl l These starting materials are further limited by
the fact that there are never more than, two chlorine atoms in allylic
positions which means that in any given compound only one of the
radicals, R, R 2 or R may contain an allylic chlorine atom Thus, for
the purposes of illustration, suh a compound may be depicted as
follows,: when R 1 represents a chloroalkyl radical, the mlecule will
contain two allylic chlorine atoms:
a 6 R 2 ',3 q 4 Ct C C = C C Cl R 7 R 5 Wherein R,, R,, R 4, RS, RG
and R, represent alkyl radicals or hydrogen atoms In the same manner
Ro or R, can contain the allylic chlorine atom and although more than
one allylie position may be present in the starting material only two
chlorine atoms may occupy the allylic positions.
Existing processes for the preparation of chloroepoxides employ the
halohydrin route for the synthesis of these compounds The p 784,620
955.
commercial process for the preparation of epichlkrhydrin is an example
of the halohydrin route and involves the addition of hypochlorous acid
to, allyl chloride and subsequent dehydrohalogenation with sodium
hydroxide to produce epichlorhydrin, salt and water This process
suffers from, the serious disadvantage that it requires the
consumption of one mel of hypochlomrus acid and one mnol of base to
produce epichloihydrin from allyl chloride.
In existing process there is also the recovery or waste problem of the
co-product sodium chloride Furthermore, problems; of corrosion are
encountered in handling aqueous sodium chloride, and the use cf
special, more expensive, equipment is necessary to avoid this
corrosion.
An advantage of the process of this invention is the production of a
single product of known structure Frequently the halohydrin route
fails to yield a pure compound This problem is especially true when
one attempts to prepare the epoxide cf a dihaloalkene For example, the
addition of hypoel-orous acid to 1,4-dichloro-2-butene yields a
compound:
Cl-CHG -CH = CH-CH- -C 1 H I OH Cl which en d-hydrohalogenation a

23. mixture of:
with base gives CH.-GCH-CH-CH 2 and Cl-CH -CH-CH-CHLC' O I I 0 Gl C 1
O The problem is also encountered with many monohaloalkenes, such as
for example, crotyl chloride Addition of hypochlorous acid to crotyl
chloride gives a mixture of:
CH,-CH-CH-GH Cl and CHI,-CH-CH-G-H C 1 r r I f OH C 1 C 1 OH which on
dehydrohalogenation with base yield a mixture of:
CH 3,-CH-CH-CH 2,C 1 and CH 3-CH-CH-CH 2 0 C 1 O The synthesis of
epichlorhydrin mentioned hereinbefore is one of the few cases where a
single product is obtained since when either chlorine atom of glycerol
dichlorhydrin is removed by dehydrohalcgenaton the same product
results.
Normally, compounds having at least one chlorine in the allylic
position are not epoxidized readily and much difficulty is encountered
in converting these compounds to epoxid-s Particularly, allyl
chloride, the parent olefin (i e, material for the synthesis) cf
epichlorhydrin, is extremely difficult to epoxidize since it is very
unreactive towards peracids, no doubt due to the fact that there are
no alkyl groups to activate the double bond.
Because of this unreactivity, high temperatures and a long reaction
period are necessary in order to effect appreciable reaction The use
oef high temperatures increases the opportunity for side reactions to
cocur with consequent losses of desired product.
The reaction illustrating the process of this invention may be
depicted as follows For the purpose of convenience, only the
characteristic allylic grouping and specific oxidizing agents, such as
peracetic acid, will be shown:
PERACETIC ACID METHOD 0 -C=C-C-Ct CCHC-0 OH- -c-ct CE' Prior to this
time, reactions of the types of compounds disclosed herein as starting
materials with peracetic acid resulted in the production of mixtures
of dihydroxy and hydroxyacetoxy derivatives of the starting materials
This undoubtedly was due to lack of purity of the peracetic acid Thus,
the use of improved oxidizing agents provides results which were never
heretofore obtainable.
Existing processes for the manufacture of lower aliphatic peracids,
and particularly peracetic acid, involve the addition of hydrogen
peroxide to acetic acid to give an, equilibrium mixture of peracetic
acid, acetic acid, hydrogen peroxide and water In the absence of added
catalyst, the rate at which the equilibriumi is reached is
impractically slow at temperatures up to about 40 C, but, on the other
hand, at higher temperatures it is difficult tom prevent excessive
loss of active oxygen.
784,620 784,620 When sulfuric acid is used as a catalyst, the phuric
acid and sa equilibrium is attained much sooner However, process ef

24. this inve the presence of sulfuric acid in the peracetic cracking of
an alipi acid mixture is not benaficial for the obtain tion product to
lit ing of satisfactory conversions of olefines to therefrom The lit
epoxides for the sulfuric acid in a peracid arated forthwith fr acetic
acid solution catalyses the ring opening of the cracking ste of
epoxides by acetic acid yielding hydroxy peracid can react acetates
appreciable extent Although the conversion of olefines to epox
aldehyde addition ides can be improved by the replacement in the
oxidation of tr whole, or in part, of the acetic acid with oxygen, at
a low te acetic anhydride, the use of anhydride may The reaction wh
lead to, the conversion of the peracetic acid to, tially free from in
the highly explosive diacetyl peroxide prepared may be i Peracids
substantially free from hydrogen general equation in paroxide, water,
mineral acids such as sul0;110 2 Cb CHOO O H 2 C&CHO, 02 low teny
Peritare CH 3 i CHCH 3 O 0 / (Acetatdch yde onoperacetate) /- % O
CH 3 C / CHC 3 crackiog eaa&t e CC-0-H CH 3 CHO O 0/ In preparing
acetaldehyde monoperacetate, oxygen is diffused into acetaldehyde at a
temperature below 15 C A temperature of about 5 C to O C is preferred
If desired, the oxygen can be in admixture with non-teactive gases,
suchi as, for example, air.
The oxidation of acetaldehyde to acetaldehyde monoperacetate is best
carried out in the presence of a catalyst Salts of the heavy nmetals,
such as salts; of cobalt, of copper and iron, are powerful catalysts
for this reaction At the same time, the presence of metal salts
decreases the stability of the peroxide that is formed and often
causes side.
reactions during subsequent use of the peroxide For good results when
a metal salt is used as the catalyst, the amount of such salt should
not exceed 5 O per cent based on the acetaldehyde inclusive of any
amount of acetaldehyde present as solvent On the other hand, an
amiount, less than 0 0001 per cent ona the same aldehyde basis has
nrot been found to be effective as a catalyst An amount which is about
O 01 per cent is preferred.
The reaction can also be catalysed by irradiating the acetaldehyde
with ultraviolet light or by a small amount of ozone in the oxygen.
Before converting the acetaldehyde mlonoperacetate to peracetic it is
usually desirable, when other solvent is; present, first to distill
off free or unreacted aldehyde.
The removal of acetaidehyde by distillation is carried out under
reduced pressure, and either a batchwise or a contirnuous distillation
procedure can be employed.
The 'succeeding step in the productions of peracetic acid from
acetaldehyde monoaperacetate, can be carried cut catalytically, or
altsi which are used in the ention, are produced by the Iatic

25. peracid-aldehyde addierate the aliphatic peracid b.erated peiacid' is
then svpIm I the aldehyde co-product ip before the aldehyde and with
one another to an The aliphatic peracidproduct can be made by he
aldehyde with molecular mperature.
ereby the peracids, substanorganic impurities, can be illustrated by
the following the case of acetaldehyde:
(I) (II) non-catalytically In D either case, provision should be made
for the rapid remdoval of the acetaldehyde co-product in order to
minin-mize 75 the formation of acetic acid from interaction of the
aldehyde with the, peracetic acid.
The cracking reaction is carried out by feeding the acetaldehyde
monoperacetate into a still kettle which; contains an inert solvent 80
under reflux; the solvent having a boiling point above the boiling
point of peracetic acid or being capable of forming an azeotrope
therewith The condenser at the still head isl mainrained at a
temperature such that per 85 acetic acid and the solvent are
condensed, while the aldehyde that is liberated is allowed to goi past
the still head and is recovered in a cold trap, There is continuously
removed from the still head the peracetic acid in the 90 form of a
solution in the particular solvent chosen.
By another procedure, the solution of acetaidehyde mlonoperacetate is
completely vaporized in a heated zone and heated to a tem 95 perature
in the range of 50 C to 250 C, approximately The vapors are then
passed to a condenser or dephlegmator maintained at a temperature
which will permit the peracetic acid to be condensed while allowing
the acer 100 aldehyde to pass through along with any other low boiling
material that might be present.
If desired, the vapors emerging fromn the heated zonee may be diluted
withan inert solvent before entry intoi the dephliegxiator and the 105
condensate recovered from the dephlegmator will thenl be a solution of
peracetic acid in the inert solvent This procedure permits a wider
choice of solvents and can be operated with solvents boiling lower
than peracetic acid 110 as well as solvents boiling higher than
peracetic acid Solvents; whi chi can be used include acetone, ethyl
acetate, acetic acid, butyl acetate and dibutyl ether.
This process provides paracids and particularly peracetic acid which
are free of impurities commonly present in peracids made by prior
metheds Solutions of peracids and particularly peracetic acid made by
this process are substantially free of water, hydrogen peroxide,
mineral acids and salts; and the concentration of any carboxylio acids
present can be, if desired, far lower than in the case of peracids
made by other methods.
In carrying out the epoxidation reaction, the allylic
chlorohydrocarbon is charged to a reaction vessel and heated under

26. reflux at atmospheric pressure The oxidizing agent is then added
gradually to, the starting material either alone or in admixture with
acetaldehyde and/ or acetone In general, the reaction can be carried
cut at any convenient temperature desired depending on the nature of
the starting material and the nature and concentration of the
oxidizing agent employed Suitable tmnperatures at which these
epoxidation reactions can be carried out are those in the range of C
to, 200 C The reaction conditions are maintained until arn analysis
for the oxidizing agent indicates that substantially all of the
oxidizing agent has been consumed.
As pointed out earlier, the presence of heavy metal ions in the
reaction mixture is undesirable, since these ions can catalyze
decomposition of the peroxide, thereby causng a low perc xide
efficiency Furthermore, this same decomposition produces free radicals
which are capable of causing the allylic chlorides to undergo
undesirable side reactions such as dimcrization and polymerization
The, great ease with which dimlerization and poclymerization occur was
shownr by Frank and Blackham (J A C S 72, 3283, 1950) for allyl
chloride and methallyl chloride It is not always easy, ho wever, to
avoid the presence of heavy metal ions, particularly since large-scale
manufacturirg processes are usually conducted in nmetal equipment We
have fcund that it is possible to overcome this difficulty by the
addition of a small amount of a sequestering agent which inactivates
the heavy m:etal ions by forming complexes with threm Very effective
sequestering agents are the alkali nmetal salts cf polyphosphates,
including partially esterified polyphosphates Examples are sodium
pyrophosphate, sodium hexametaphosphat disodium dimethyl
pyrophosphate, and the "Victawet" anionic wetting agents such as
"Victaw vet B", Na ( 2-ethylhexyl)-(P,01 o)2 Other types of
sequestering agents, for exampll, gluccnic acid,
ethylenediaminetetracetic acid, sodium silicate, and the commercially
available "Perma Kleers", manufactured by Refined Products
Corporation, may also b used.
Small amounts of compounds which inhibit the decomposition of the
peracid due to the presence of metal ions may also be added.
Examples of such inhibitors are pyregallol, trinitrobenzenz and sedium
pyrophosphate.
After the reaction period is over the reaction 70 mixture can be
worked up in any convenient manner and the epoxide recovered by any
convenient nmeans, such as distillation or extraction.
In the examples, the analysis for the epoxide 75 group is based upon
its reaction with pyridine hlydrochloride to, form the chlorhydrin and
pyridine Into a pressure bottle containing 23 milliliters of l N
pyridine hydrochloride in chloroform was intreduced a sample of 80

27. epcxide calculated to use about 50 per cent of the pyridin:
hydrochloride The bottle was then closed and the contents heated in a
steam bath for a period of one hocur At the end of that time, the
bttle and contents were cooled, 85 drops of phenolphthalein indicator
( 1 0 gram per 100 milliliters of 60 per cent ethanol) added, and the
mixture titrated to a permanmnt red endpoint with standard 0 2 N
alcoholic potassiuml hydroxide solution A blank 90 was also run in
precisely the same fashion except that the sample was omitted The
preparation of the, oxidizing agents is illustrated below:
PREPARATION I 95 PREPARATION OF PERACETIC ACID An acetone solution
containing 202 grams of acztaldehyde moncperacetate in a total of 422
grams of solution was mixed with 300 grams of cold dibutyl ether' and
the whole fed 100 dropwise ever a period of 2 1 hours into a
steam-heated (temperature 980 C to 98 50 C) flask of two liters
capacity The flask was fitted with a steam-heated tube leading to a
water-cooled condenser having at its discharge 105 end a receiver
surrounded by ice water The pressure inside the equipment was
maintained at 48 to 55 millimiters of mercury, absolute There was
collected 417 grams of distillate having a peroxide content corres 110
peonding to, 81 grams of peracetic acid This distillate which still
contained a small amount cf acetaldehyde m onoperacetate was then
again fed dropwise through the same apparatus over a period of eighty
minutes under 115 the same, conditions From the second pass there was
obtained 388 grams of solution containing 75 gramns of peracetic acid
The overall yield of peracetic acid from acetaldehyde mrncperaceta te
was 60 per cent 120 PREPARATION II PREPARATION OF PERPROPIONIC ACID A
solution of 270 grams of propionaldehyde and 90 grams of isopropyl
acetate was charged to, a cylindrical glass oxidizer and cooled to 125
-4 C The solution was irradiated with ultraviolet light, and oxygen,
was introduced through a diffuser near the bettom of the oxidizer for
a period of two hours At the end of that time there was obtained 398
130 784,620 584,6201 grams of solution which was found upon analysis
to contain 43 6 per cent by weight of propionaldehyde
monoperpropionate This solution was mixed with, 0 3 liter of isopropyl
acetate cooled to a temperature of 5 C to which had previously been
added 0 4 gram of Nai( 2-ethylhexyl),(PO 00), (Victor Stabilizer No
53) dissolved in 4 milliliters; of propionic acid Unreacted
propionaldehyde was removed from the solution under a reduced pressure
of 10 millimeters of mercury, absolute, with the kettle contents
maintained at a temperature of about -5 C to O C The resulting
solution, weighing 427 grams and analyzing 39 per cent propionaldehyde
monoperpropionate, was fed through a stainless steel, steam-heated
vaporizer to the mid-section of a three-foot stainless steel-packed
column at the rate of 0 1 to 0 2 liters per hour The column was

28. operated at an absolute pressure of 50 millimletersl of mercury and
with a head temperature of 18 C to 21 C.
Isopropyl acetate was fed through a steamheated vapuorizer into the
column near the bottom at the rate of 0 16 to} 0 22 liter per hour An
isopropyl acetate solution taken from the bottom of the column
continuously during the run weighed 443 grams and contained 17 5 per
cent by weight of perpropionic acid by analysis The yield based on the
propionaldehyde maonoperpropionate obtained from the oxidizer was 76
per cent.
The invention will be illustrated by reference to the following
Examples:
EXAMPLE I.
PREPARATION OF CHLOROISOBUTYLENE OXIDE FROM METHALLYL CHLORIDE
AND
PERACETIC ACID Methallyl chloride ( 543 grams) containing 0 2 per cent
of pyrcgallol inhibitor was heated under reflux at atmospheric
pressure (kettle temperature 72 C) irn a kettle equipped with a 3-foot
column packed with glass helices.
Over a period of 2 hours and 20 minutes, 503 grams of a 30 2 per cent
solution of peracetic acid in acetone was added to, the kettle The
kettle temperature remained at 72 C throughout the addition After am
additional 2 5-hour reaction, period the reaction mixture was allowed
to stand overnight at room temperature The reaction mixture was then
fractionally distilled A 70 per cent yield of chioroisobutylene oxide
was obtained in a cut boiling at 40 C to, 50 C at 50 min pressure
which contained about equal weights of acetic acid and the oxide A
portion of this mixture was ste;am distilled under 200 mmn pressure.
The chloroisobutylene oxide came over at 58 C and separated out as a
lower layer which was continuously removed After drying, the oil layer
(n,'0 1 4280) analyzed 99 5 per cent as chloroisobutylene oxide, using
pyridine hydrochloride in chloroform as the analytical reagent.
EXAMPLE II 65
PREPARATION OF 3-CHLORO-1,2-EPOXYBUTANE FROM 3-CHLORO-1-BUTENE AND
PERACETIC ACID A solution of peracetic acid ( 1460 grams of a 20 7 per
cent solution) in acetone was added 70 dropwise over a period of 4
hours to'1448 grams of 3-chloro-1-butene containing 2 8 grams of
trinitrobenzene as an inhibitor The temperature was maintained at 58 C
to 60 C throughout the addition An additional 8 75 hour reaction
period at this same temperature was required before the peracetic acid
was substantially all reacted ( 91 per cent) The reaction mixture was
stripped of excess chloroalkene and acetone under reduced pressure 80
The residue was diluted with 500 grams of carbon tetrachloride and
washed three times with water to' remove acetic acid The washed oil
layer was then distilled under reduced pressure The cuts boiling

29. between 45 C and 85 C at 50 mm pressure had a purity of 90.5 per cent
as judged by an analysis for epoxide by the pyridine-hydrochloride in
chloroform, method Distillation of the water wash material gave
additional epoxide The 90 combined yield, based on peracetic acid, was
68 per cent of the theoretical.
EXAMPLE III.
PREPARATION OF 1,4-DICHLORO-2,3-EPOXYBUTANE FROM 1,4-DICHLORO-2-BUTENE
95 AND PERACETIG ACID A solution of peracetic acid in acetone ( 708
grams of a 21 5 per cent solution) was fed dropwise with stirring to a
flask containing 1000 grams of 1,4-dichloro-2-butene at 60 C 100 After
adding approximately one-half of the peracetic acid an analysis
indicated that the reaction was proceeding slowly The temperature was
raised ta 800 C to 88 C and the addition continued A total of 4 hours
was 105 required for the addition to be completed.
The reaction was; continued for an additional 2 hours at 80 C to, 88 C
After standing overnight at ronrr teamperature the reaction mixture
was fractionally distilled The pro 110 duct was a colourless liquid
boiling at 66 C.
to 68 C and 5 mmlin pressure and was obtained in a yield of 82 per
cent (based on peracetic acid) It was identified as
1,4dichloro-2,3-epo xybutane by the following: 115 n D 30 = 1 4743 Sp,
Grav - C = 1 3112 Calc.
Molecular Refraction Oxygen Analysis Epoxide Analysis (morpholine
mnethod) 30.55 11.35 % % Found 30.20 11.64:11 70 % 120 93.5 % The
infra-red spectrum had a characteristic absorption peak at 7 85
microns, the same as epichlorohydrin and ethylene oxide The material
also showed absorption at two other points (though these are less
characteristic) commonly attributed to the epoxide group.
EXAMPLE IV.
PREPARATION OF EPICHLOROHYDRIN FROM ALLYL CHLORIDE AND PERACETIC 9
ACID A solution ( 256 grams) of peracetic acid ( 32 7 per cent) in
acetone containing O 5 grams cf sodium: pyrophlo sphatre was added
dr;cpwise over a period cf 1 hour to a boiling ksttle of allyl
chloride ( 430 grams) The reaction mixture was heated under reflux
(temperature 500 C to 53 C) for an additional 6 hours, at which time
an analysis for peracetic acid indicated that 89 per cent of it had
reacted The excess allyl chloride and acetone were removed from the
reaction mixture by distillatiorn at 170 mi pressure The pressure was
reduced and the product, epichlorohydrin, was distilled as a mixture
with acetic acid.
The epichlorohydrin and acetic acid were separated by steam
distillation under reduced pressure ( 120 nmn) The lower layer was
reml.ved continuously from the distillate, dried over sodium sulfate
and distilled on, a Vigreux column to give a 50 per cent yield of

30. epichlorchydrin: having a boiling point of 52 C.
at 74 mm pressure.
Per Cent Run Reaction Sequestering No Time Agent EXAMPLE V.
PREPARATION OF EPICHLOROHYDRIN A method of analysis for
epichlorohydrin in the presence of acetic acid and allyl chloride was,
developed and checked against synthetic mixtures The method involved
the reaction of pyridinium chloride in chloroform solution with
epichlorohydrin with a correction made for the acetic acid present
This method gave accurate values for known compositions of acetic
acid, epichlorohydrin, and allyl chloride.
A series of runs was, made in a stainless steel bomb to chck the
effect of a sequestering agent and various inhibitors cn the reaction
between Fpracetic acid and allyl chloride At the end of the reaction
the reaction mixtures were distilled and were analyzed by the above
meathod This gave an accurate value of the yield of epichlcrohydrin
The losses and the time involved in separating epichlorohydrin fromt
acetic acid on a small scale were thus elimlinated In each of these
runs the molar ratio cf allyl chloride to peracetic was to 1, and the
reaction temperature was 60 C The sequestering agent was Na,(
2-Ethylhexyl),,(PO,,)2 "Victawet 35 B".
A suirnary of these runs is given in the following table:
%' Inhibitor Yield of Epichlorohydrin ( 1) 7 5 hrs.
( 2) 7 hrs.
( 3) 10 hrs.
( 4) 8 hrs.
( 5) 9 hrs.
( 6) 8 5 hrs.
0.05 %, 0.1 % 0.1 % r 0.1 % 1 0.1 % 0 1 % None None 0.1 %,
trinitrobenzene 0.1 %'o 2,4-dinitro-6chlorophenol 0.1 ','
2-nitro-4-chloroaniline 0.1 %' phenyl-betanaphthylamine EXAMPLE VI
CONTINUOUS PREPARATION OF EPICHLOROHYDRIN AT 100 %C.
Epichlorchydrin was prepared continuously by passage of al mixture of
allyl chloride and Allyl chloride % solution of Victawet 35 B in
acetic acid Peracetic acid solution in acetone ( 24 7 '%) and put
under 75 pounds per square inch nitrogen pressure and passed through a
coil made of 1/8-inch stainless steel tubing having a volume of 67 cc
The tube effluent was peracetic acid solution through a stainless
steel coil under pressure and heated to 100 ' C.
with steam' The following charge stock was made up:
530 grams 0.95 cc.
451 grams analyzed for Feracntic acid and for epichloro 80 hydrin as
described in Example IX The results are recorded in the following
table:
66 ' 76 %', 84.1 %, 84.9 %' %,, 61 ',, 784,62 o 784,620 Rul No.

31. Fe-d rate Temp Pressure cc/hr.
( 1) 100 C 75 psi 230 ( 2) 100 C 75 psi 110 EXIMPLE VII.
PREPARATION OF 3,4-DICHLORO-1,2EPOXYBUTANE Twenty In O os ( 2500
grams) of 3,4-dichloro1-butene was placed in a three-necked 5-liter
flask equipped with a stirrer, thermometer, and dropping funnel A
weight cf 2 5 grams ( 0.1 % by weight of the olefin) of Nas(
2-Ethylhexyl),(PO 00)2, "Victawet 35 B", was added as a stabilizer
Then, with stirring at 75 , five mols of 25 O per cent peracetic acid
in acetone was; added over a three-hour period After heating for an
additional one and one-half hours, analysis for peracetic acid showed
that a conversion of 89 per cent had been achieved.
The reaction mixture was charged to, a distillation kettle attacked to
a packed 24 " glass column Then, at 50 , the acetic acid and acetone
were removed by flash distillation It was; observed that the last
amounts of acetic acid distilled as, an azeotrope with unreacted
3,4-dichloro-1-butenr The remaining material was carefully
fractionated to obtain pure unareacted chloro:olefin and the desired
epoxide.
A total cf 471 grams ( 75 per cent) of 3,4dichroro-1,2-ep:oxybutane
was obtained The epoxide distilled at 43 at 2 mm pressure.
Arn index of refraction of N O = 1 4740 was observed for this compound
Arn analysis for epoxide by the "pyridine hydrochloride in chloroform"
method indicated a purity of 93 3 per cent However, no foreign groups
such as olefin, carbonyl, or hydroxyl, were found to be present by an
infrared absorption examination Redistillation gave material of the
same physical proper;ties, indicative of the presence of a single
compound.
EXAMPLE VIII
PREPARATION OF 2,3-EPOXY-2-ETHYLHEXYL CHLORIDE (a) Preparation of the
unsaturated halide To a mixture of 256 grams of 2-ethyl-2hexenol and
167 grams of pyridine was added, over a period of 2 3 hours, 319 grams
of thionyl chloride at a temperature of approxi-mately O C The
reaction mixture was then held at 5 C for 1 hour and then heated to 70
C for an additional 3 hours The reaction mixture was cooled, diluted
with 600 cc of hexane, and poured into 1500 grams of ice and water
with vigorous agitation The organic layer was separated and washed
twice with dilute sodium carbonate solution Distillation gave a 49 per
cent yield of 2-ethyl-2Contact minutes mnuntes 17.4 36.5 01 Peracetic
Consumed 89 96.2 % Yield of Epichlorohydrin 81.5 % 86 % hexenyl
chloride having a boiling point of 52 C tot 54 C at 10 mm pressure and
a refractive index range of 1 4449-1 4485 (n a 0).
The refractive index range is probably due to the product's being a
mixture of cis and trams isomers Analysis for allylic chlorine by
saponification and determination of chloride ion by the Volhard method

32. indicated a purity of 92 per cent Quantitative bromination analysis
indicated a purity of 96 per cent.
(b) Preparation of the epoxide A solution of peracetic acid in acetone
( 390 grams of a 22 per cent solution) was added over a period of 1 5
hours to'110 ' grams of 2-ethyl-2-hexewnyl chloriderat a temperature
of C The temperature was raised to 50 C.
and the reaction allowed to continue for an additional 4 hours Toluene
( 300 cc) was added, and the acetone was removed by distillaticn under
reduced pressure The residue was washed with water to remove acetic
acid and then fractionated under reduced pressure.
A 67 per cent yield of 2,3-epoxy-2-thylhexyl chloride, a colourless
liquid boiling at 70 C.
to 71 C at 10 mm pressure and having a refractive index of 1 4420
(n,)0) was cbtained.
An analysis by the pyridinium-chloride-inchloroform method for e
Foxide indicated a purity of 94 %.
EXAMPLE IX "PREPARATION OF 1-CHLORO-2,3-EPOXYBUTANE FROM CROTYL
CHLORIDE AND PERPROPIONIC ACID " A solution ( 614 g) of 28 3 %
perpropionic 90 acid ( 1 93 mols) in' ethyl propionate was added
dropwisei over a period of one hour to 177 g cf crotyl chloride ( 1 96
mols) with stirring at a temperature of 40 C The reaction mixture was
then heated an additional 95 7 hours at 40 C after which time
approximately 90 % of the peracid had been consumed The reaction
mixture was cooled and diluted with 500 ml of chleoroeform and washed
with sodium bicarbonate solution 100 until substantially free of acid
Rapid distillation of the washed solution under reduced pressure (
100-70 ramin) gave 183 g of crude 1-chloroe-2,3-epoxybutane
contaminated with ethyl propionate and somea propionic acid 105
Redistillation at 40 mm gave 115 g ( 56 % yield based en peracid) of
1-chloro-2,3-epaxybutane, a colourless liquid having a boiling point
of 49 C at 50 mm and, a refractive index of 1 4286 (n O ) 110
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* GB784621 (A)

33. Description: GB784621 (A) ? 1957-10-09
Improvements in or relating to conductive elastomeric compositions and
method of making
Description of GB784621 (A)
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The EPO does not accept any responsibility for the accuracy of data
and information originating from other authorities than the EPO; in
particular, the EPO does not guarantee that they are complete,
up-to-date or fit for specific purposes.
COMPLETE SPECIFICATION
Improvements in or relating to Conductive Elastomeric
Compositions and method of making
We, THE CONNECTICUT HARD RUBBER
COMPANY, a corporation organized under the laws of the State of
Connecticut, one of the
United States of America, of 407, East Street,
New Haven, State of Connecticut, United
States of America, do hereby declare the invention, for which we pray
that a patent may be granted to us, and the method by which it is to
be performed, to be particularly described in and by the following
statement: -
This invention relates to conductive rubber compositions and more
particularly to rubber compositions capable of retaining a high degree
of electrical conductivity under flexure.
Electrically conductive rubbers are useful, for example, in shoe soles
for preventing build-up of static charges by providing a leakage path
to ground. Other uses include heating blankets or coverings, radiant
heaters, conducting gaskets, electric potential distributors and
various other applications.
In the prior art, carbon black modified rubber compositions have
displayed some degree of conductivity. The electrical conductiveness
of these compositions, however, depends on the maintenance of
continuous chains of carbon particles within the body of the material
which become ruptured through continual fiexure and distortion
resulting in partial or total loss of electrical conductance.

34. A primary object of the present invention is to provide elastomeric
rubber compositions wherein the rubber is modified in such a manner as
to provide an electrolytic medium for the transfer of current through
the body of material and which is substantially unaffected by flexure
and distortion of the rubber for an indefinite period of time. By
virtue of being electrolytic conductors, the compositions described
herewith are electrically conductive throughout every element of
volume of the materials which contain both positive and negative ions,
rather than being conductive only through chains of electronically
conducting carbon particles interspersed in a continuous
non-conducting medium. The inherent difference between our conducting
compositions and those of the prior art is therefore two-fold:
electrolytic versus electronic, and continuous throughout volume
versus discontinuous end dependent on continuous threads or chains of
filler.
The electrically conducting elastomers formed in accordance with the
present invention are primarily characterized by two principal fields
of use or application. The first application is in the antistatic
field, wherein the ability of the rubber to conduct permits static
charges to leak to ground, thereby preventing the build-up of high and
often dangerous potentials. Practical examples are conducting gaskets,
shoe soles and tires. The second application is in the heating field,
wherein the ability of the rubber to conduct causes the rubber to
produce heat when an external voltage is applied to a block or sheet
of the material. Examples of the latter class of applications include
airplane de-icers, radiant heaters, and heating blankets, tapes, and
coverings.
Elastomers in general, as defined by Harry
S. Fisher, in Industrial and Engineering
Chemistry, Vol. 31, No. 8, pp. 941-945, of
August, 1939, have properties which resemble those of natural rubber
including very high electrical resistance, elasticity, elongation,
tensile strength and the like. Such elastomeric compositions are
especially characterized as possessing to a high degree physical
strength, abrasive resistance and insulating properties relative to
the passage of electrical current.
Electrolyte solutions, on the other hand, are liquids characterized by
a high electrical conductivity without physical strength. An important
aspect of the invention is to provide a composition which in a novel
manner combines the conductivity of electrolyte solutions with the
physical strength, flexibility and abrasive resistance of the
synthetic elastomers.
The conductance of an electrolyte in a solvent depends on the chemical
composition of the electrolyte and its concentration and especially on

35. the viscosity and dielectric constant of the solvent. For a given
concentration of a particular electrolyte, the conductance is higher,
the lower the viscosity of the solvent medium and the higher its
dielectric constant.
Elastomers such as natural rubber and styrene-butadiene copolymers,
while elastic solids from the macroscopic point of view, are
liquid-like from the microscopic point of view of molecular motion.
The local viscosity of many elastomers is high, but can be markedly
reduced by the incorporation of certain liquids of low vapor pressure,
known to those skilled in the art as plasticizers.
Electrolytes in general are not soluble in organic liquids, but
certain special classes of electrolytes such as quaternary ammonium
compounds, sulfonium compounds, phosphonium compounds, and iodonium
compounds, are soluble, and, in accordance with the invention, it has
been discovered that the solubility in general of these soluble
electrolytes increases with the dielectric constant of the solvent.
The invention described herein depends on a novel combination of
properties achieved by compounding an elastomer which contains polar
comonomers such as acrylonitrile with a polar plasticizer such as
dimethyl-sulfolane to give a medium of high enough dielectric constant
to dissolve quaternary and similar electrolytes.
By adding a polar plasticizer, the dielectric constant is further
increased, and simultaneously the local viscosity is decreased.
The effect of the high dielectric constant plasticizer is to insure
solubility of the electrolytic solute and especially to increase the
degree of ionization of the electrolyte. The effect of the lowered
viscosity is to increase the mobility of the ions of the electrolytes.
These effects combine to produce an elastomer which, in addition to
the normal mechanical properties of a similar elastomer which contains
no electrolyte, possesses an electrical resistance many powers of ten
lower.
This unique and novel combination of properties is obtained by a
conductive rubber composition comprising a polar synthetic elastomer
having a dielectric constant of at least 5.0, a polar plasticizer
having a dielectric constant of at least 10.0 which is compatible with
the elastomer and an electrolyte which is soluble in the plasticizer.
The three types of materials referred to, namely, the polar elastomer,
polar plasticizer and electrolyte, reinforce their own several
properties in a unique and distinctive manner and impart conductive
properties to the elastomer never before achieved.
Certain of the currently recognized elastomers have polar
characteristics which render them particularly amenable to the
practice of the invention. For example, "Hycar" (Registered Trade
Mark), an acrylonitrile-butadiene copolymer and " Neoprene," a

36. polychloropreys, "Thiokol" (Registered Trade Mark), a polyethylene
sulfide and other highly polar polymers are especially suitable and in
general any high dielectric constant elastomer having at least 15 7o
of a polar comonomer may be employed to produce an effectively
conductive composition.
In accordance with the invention, it has been found that the
properties of relatively high dielectric constant elastomers having
polar characteristics may be suitably modified to form a medium having
remarkably low resistance to current flow. It has further been found
that current transfer in such a medium is drastically increased by the
presence of small quantities of electrolytes which appear to function
through ionic movement as in electrolyte solutions. In order to
provide a medium which will allow the proper functioning of the
electrolyte, the internal viscosity of the elastomer is modified by a
plasticizer having a relatively high dielectric constant which is
compatible with the elastomer and which also contains polar groups.
For purposes of this description, by dielectric constant, we mean the
value of the constant measured at relatively low frequencies, e.g.,
1,000 cycles and room temperature.
All elastomers do not provide an appropriate solvent medium for the
conductive electrolyte salts. Appropriate elastomers for purposes of
the invention are those having a content of at least 15 -o of a highly
polar comonomer such as acrylonitrile or chloroprene, and, further,
have a dielectric constant of at least 5.0 and preferably over 7. With
this is combined a highly polar plasticizer having the property of
modifying the internal viscosity, dielectric constant, and resistivity
of the polar elastomer.
The conventional plasticizers such as tricresyl phosphate, dibutyl
phthalate and dioctyl phthalate do not have the dielectric and other
properties for purposes of the invention. The suitability of a polar
plasticizer for purposes of the invention is in general measured by
the dielectric constant of the material. For example, tricresyl
phosphate having a dielectric constant of 7.0 at 25 C., dibutyl
phthalate having a dielectric constant of 6.4 at 30 C., and dioctyl
phthalate having a dielectric constant of 5.1 at 25 C., are found to
not have the polarity and solvent requirements suitably to modify the
electric conductiveness of the elastomer.
The addition of a selectively polar plasticizer to the polar elastomer
has the property of substantially increasing the dielectric constant
of the elastomeric conductive medium.
This increase in dielectric constant by the plasticizer is primarily
the consequence of a reduction of the internal or local viscosity of
the elastomer. For a given dipole content (measured as number of polar
groups per unit volume), the dielectric constant at a given

37. temperature and frequency is higher the lower the viscosity.
Furthermore, the dipoles of the plasticizer molecules also contribute
substantially to the dielectric constant of the aggregate. Among the
suitable polar plasticizers for purposes of the invention may be
mentioned the cyclic and aromatic sulfones, alkyl and aryl nitriles,
nitro-compounds, and the alkoxy esters of dibasic carboxylic acids. In
order to favorably affect the conductive properties of the elastomeric
medium, the plasticizer should have a dielectric constant of at least
10 and preferably 20 or above. When incorporated into the elastomeric
conductive medium in proportions of from 35 to 85 parts of plasticizer
to each 100 parts of elastomer, the effect on the conductivity of the
elastomeric medium increases as an exponential factor when the
dielectric constant of the plasticizer is 20 or above. The plasticizer
must further be entirely compatible and miscible within the indicated
ranges with the elastomeric medium and furthermore be a solvent for
the electrolyte.
For example, the plasticizers, when incompatible with the elastomeric
conductive medium, cause the composition to break down and crumble
when mixed in a rubber mixing mill or, in certain cases, although
appearing initially to be miscible, will later form a "bloom" on the
surface of the product after aging.
Suitable electrolytes for purposes of the invention may be the
sulfonium, phosphonium and iodonium salts, salts of carboxylic acids
and other electrolyte salts which are soluble and miscible with the
plasticized elastomeric conductive medium. The quaternary ammonium
salts have been found to be particularly suitable.
Referring again to the elastomeric medium, the dielectric constant of
elastomers (a) having suitable characteristics for the practice of the
invention are compared with the dielectric constants of (b) ordinary
rubber and of a low dielectric constant elastomer in the following
table:
TABLE I
Dielectric Loss Factor D.C. Volume
Constant 1 kcps at Resistivity
No. Gum 1 kcps at RT RT (XlO9ohm-cm)
E263 Hypalon S--2 7.70 1.02 400.
E264 Neoprene 6.40 0.567 268.
E265 Thiokol & T 7.35 0.544 39.4
E266 Hycar 1014 10.0 1.56 3.44
E267 Hycar 1013 11.9 1.30 4.57
E268 Hycar 1002 13.5 1.69 2.92
E269 Hycar 1001 16.5 2.94 1.12
E261 Smoked sheet 2.58 0.161 400
E262 GR-S 2.44 0.146 400

38. An elastomeric composition having the required characteristics is
suitably incorporated with a high dielectric constant plasticizer
having the property of raising the dielectric constant, reducing the
internal viscosity and/or lowering resistivity of the conductive
medium.
Suitable polar plasticizers and their effect on reducing the DC volume
resistivity of Hycar 1001 are illustrated in the following table:
TABLE II
DC Volume
Compound Parts Resistivity
No. Parts Polar Compound TEAB (megohm-cm)
550a - - - 470.
570 - - 5.0 73.
559 50.0 ss,ssl-Oxydipropionitrile - 1.1
560 50.0 ,, 5.0 0.12
543 50.0 Dimethylsulfolane - 21.
571 50.0 " 5.0 0.59
572 50.0 2-Nitro-p-cymene 5.0 3.6
574 50.0 Anisonitrile 5.0 1.1
575 50.0 Benzonitrile 5.0 1.8
576 50.0 o-Nitroanisole 5.0 0.51
577 50.0 Methyl-o-nitrobenzoate 5.0 1.7
It will be appreciated from the foregoing
Table II that while the unplasticized Hycar containing the electrolyte
TEAB (Tetraethylammonium bromide) had a DC volume resistivity of 73,
the addition of 50 parts of beta, beta'-oxydipropionitrile to 100
parts of the elastomer reduced the DC volume resistivity of the
composition to approximately 0.12.
In other words, the addition of the plasticizer reduced the
resistivity by a factor of over 600.
The addition of other plasticizers of the type listed in the Table had
a corresponding effect upon the DC volume of resistivity of the
elastomeric conductive medium.
As ordinarily manufactured in standard commercial practice,
plasticizers contain small amounts of electrolytic materials arising
from the reagents used in the synthesis, either as byproducts or
impurities. It is not necessary to state the chemical composition of
these electrolytic substances; it is well known to all who have worked
with organic liquids that electrolyte is often present in these
liquids as received, because purification methods invariably increase
their electrical resistance. In the practice of the present invention,
it is planned that this purification will not be carried out, so that
the normally present electrolyte in the plasticizer will lower the
resistance of the elastomer to which it is added by the contribution

39. to conductance from the electrolyte content of the plasticizer.
In the above Tables, it will be observed that a substantial
conductivity was achieved through the mere addition of the polar
plasticizer to the elastomer indicating the presence of electrolyte
substances in the plasticizer. It will be appreciated that in many
cases the presence of electrolytic material in the polar plasticizer
imparts sufficient conductivity to the resulting elastomer so that
further addition of quaternary salts or other electrolytes can be
dispensed with.
The following Examples are illustrative of elastomer compositions
prepared according to the teachings of the invention and displaying
unusual conductive properties in accordance therewith:
EXAMPLE 1
A copolymer was prepared consisting of substantially 39 parts by
weight of acrylonitrile and 61 parts by weight of butadiene. The
copolymeric elastomer was found to have a dielectric constant of 16.5,
which contrasted greatly with the dielectric constant of 2.04 of a
copolymer of butadiene and styrene, or the dielectric constant of 2.58
of natural rubber.
The high dielectric constant of the nitrile rubber was believed to be
attributable to the presence of the nitrile group, providing polar
groups within the elastomer, thereby raising the dielectric constant.
A sample of dimethyl sulfolane (2,5-dimethyl tetramethylene sulfone)
was tested and found to have a dielectric constant of 29.
Elastomeric mixtures consisting of essentially 50 parts of
dimethylsulfolane and 100 parts of the copolymer of acrylonitrile and
butadiene were found to have dielectric constants of the neighborhood
of 19.
A composition was prepared consisting of:
Elastomer
Copolymer 100 parts
Modifier 64 parts
The modifier consisted of:
Plasticizer
Dimethylsulfolane 50
Salt
Phenyltrimethylammonium iodide 5
Filler
Zinc oxide 5
Softener
Stearic acid 1
Curing agent
Tetramethylthiuramdisulfide 3
64

40. The composition was compounded by incorporating the elastomer with the
plasticizer in a conventional rubber mill. This was milled for 15
minutes, during which time the filler was periodically added in small
quantities, followed by the incorporation of the quaternary salts and
other ingredients. The composition was then milled an additional 15
minutes, placed in a mold and press-cured for a period of 30 minutes
at 300 F. The resulting rubber article had a direct current volume
resistivity of 0.58 megohm per centimeter cube and an alternating
current volume resistivity of 0.54 megohm per centimeter cube. The
electrical conductivity remained unchanged after severe flexing tests.
EXAMPLE 2
A rubber article was prepared using the modifier of Example 1 but
employing Hycar 1001 as the elastomer. Hycar 1001 is a copolymer of
acrylonitrile and butadiene, containing approximately 39%
acrylonitrile, and is sold by the B. F. Goodrich Company of
Akron, Ohio. The article resulting from the curing of the composition
had electrical conductivity characteristics substantially the same as
the article of Example 1.
EXAMPLE 3
A rubber article was prepared essentially according to Example 1, and
utilizing the curing agents of Example 1 in an elastomeric mixture
consisting essentially of 100 parts of a polychloroprene, 50 parts
dimethyl sulfolane and 5 parts of laurylisoquinolinium bromide.
The cured product had a DC resistivity of 2.1 megohm per centimeter
cube. The higher resistivity of the neoprene product was believed to
be attributable to the fact that the chloro group was not as effective
as the nitrile group in increasing the dielectric constant of the
elastomeric material.
EXAMPLE 4
A cured article was prepared essentially as in Example 3, with
laurylisoquinolinium bromide as the salt but with dimethoxyethoxyethyl
adipate as the plasticizer. The product had a direct current
resistivity of 5.8 megehms per centimeter cube.
EXAMPLE 5
By substituting 50 parts of octadecylnitrile as the plasticizer in the
composition of Example 4, a cured article was prepared having a direct
current resistivity of 9.3 megohms per centimeter cube.
EXAMPLE 6
A cured rubber article was prepared from a composition consisting
essentially of 100 parts of Thiokol (a polyethylene-polysulfide sold
by the Thiokol Corporation), 50 parts of dimethyl sulfolane and 5
parts of phenyltrimethyl ammonium iodide and the curing agents
outlined in Example 1. The cured rubber article had a DC volume
resistivity of 0.71 megohm per centimeter cube and an AC volume

41. resistivity of 0.59 megohm per centimeter cube.
EXAMPLE 7
A mixture was prepared consisting of equal parts of dimethylsulfolane,
octadecylnitrile, tetramethylene sulfone, dimethoxyethoxyethyladipate
and several similar plasticizers, each having a dielectric constant
significantly above 15, plus about 10 to 40 per cent of equal parts of
tetraethylammonium bromide, laurylisoquinolinium bromide,
phenyltrimethylammonium iodide, phenyltrimethylammonium bromide,
triethylmethylammonium p-toluene sulfonate, methyl pyridinium
p-toluene sulfonate and several other quaternary salts having anions
of strong acids, and this mixture or an equivalent mixture of a single
high dielectric plasticizer and a single quaternary salt, was used to
impart improved electrical conductivity to an elastomeric mixture
comprising
Hycar 1001, neoprene, Thiokol, and/or other elastomers having a
dielectric constant significantly greater than that of the hydrocarbon
rubbers, for example, a dielectric constant greater than 7.
EXAMPLE 8
An article was prepared from a composition comprising:
Elastomeric material
Elastomer
Hycar 1001 100 parts
Plasticizer
Dimethylsulfolane 50
Quaternary salt
Salt having strong anion
Laurylisoquinolinium bromide 5
Supplementary materials
Curing agent
Tetramethylthiuramdisulfide 3
Filler
Vulcan S C carbon black 50
The article was cured at 310 F. to produce a rubber having both
excellent mechanical and excellent electrical properties. Tests showed
that the cured article had:
Hardness (Shore A) 45
Elongation 500 %
Tensile strength 1987 psi.
Megohm per centimeter cube 0.0028
Abrasion tests demonstrated that carbonfilled elastomers of the
present invention were well suited as shoe soles, and in actual
wearing tests, the conductive rubber shoe soles of the present
invention proved superior to those previously available.
EXAMPLE 9

42. A rubber composition was prepared essentially in accordance with the
method of the preceding Examples, including the following components:
Hycar 1001 100 parts
Tetraethylammonium bromide 5
ss,ssl-Oxydipropionitrile 50
Silene EF (filler) 125
Age Rite Alba (antioxidant) 0.4
Stearic acid (processing agent
or activator) 2
Altax (Registered Trade Mark) 1
Methyl Zimate (accelerator) 0.16
Zine Oxide (accelerator) 5
Sulfur (curing agent) 3
A composition prepared in accordance with the teachings of the
previous Examples demonstrated a direct current resistivity of 0.088
megohms per centimeter cube, hardness of 71 by the Shore method,
tensile strength 788 psi., elongation 175,n, tear strength 123 lbs.
per inch.
The following Table illustrates the effect on volume resistivity of
incorporating polar plasticizers having dielectric constants of
between 10 and 40 in various synthetic elastomers:
EFFECT OF COMPOUNDING DIMETHYLSULFOLANE
PLASTICIZER IN VARIOUS RUBBERS
<img class="EMIRef" id="026700845-00060001" />
I
Parts of Volume Resistivity
No. Gum Essential Ingredients DC (x 106
ohm-cm)
377 Hycar 1001 None 1,000.
378 " 5.0 LIQB 250.
379 " 50.0 DMS 21.
380 " 5.0 LIQB + 50.0 DMS 5.0
396 " 5.0 LIQB + 50.0 TCP 210.
381 Neoprene GN None 47,000.
382 5.0 LIQB 2,000.
383 " 50.0 DMS 2.3
384 " 5.0 LIQB + 50.0 DMS 2.1
397 " 5.0 LIQB + 50.0 TCP 110.
385 Thiokol ST None 10,000.
386 " 5.0 LIQB 1,500.
388 " 5.0 LIQB + 50.0 DMS 1.6
389 GRS None
390 " 5.0 LIQB
391 50.0 DIS 50,000.

43. 392 5.0 LIQB 3- 50.0 DMS 51,000.
399 5.0 LIQB 3- 50.0 TCP 58,000.
415 Smoked sheet None > 400,000.
416 5.0 LIQB > 404000.
417 50.0 DIS > 404000.
418 v 5.0 LIQB + 50.0 DMS > 400,000.
419 " 5.0 LIQB + 50.0 TCP > 400,000.
DMS = Dimethylsulfolane, LIQB = Laurylisoquinolinium bromide,
TCP = Tricresylphosphate.
From the above reported experimental work, it will be observed that
the incorporation of the highly polar dimethylsulfolane plasticizers
reduced the DC volume resistivity from 1,000 to approximately 21.0, in
the case of Hycar 1001 from 2,000 to approximately 2.3, in the case of
Neoprene GN and with
Thiokol ST from 10,000 to approximately 1.6 with the addition of a
small quantity of electrolyte.
In the case of Neoprene GN, the presence of electrolyte in the
plasticizer was sufficient after the addition of the plasticizer to
reduce the DC volume resistivity from 47,000 to approximately 2.3. The
further addition of electrolyte, it will be observed, had little
effect in securing a further reduction of the resistivity.
What we claim is: -
1. A conductive rubber composition comprising a polar synthetic
elastomer having a dielectric constant of at least 5.0, a polar
plasticizer having a dielectric constant of at least 10.0 which is
compatible with the elastomer and an electrolyte which is soluble in
the plasticizer.
2. A composition as set forth in claim 1 in which the elastomer has a
dielectric constant over 7.0.
3. A composition as set forth in claim 1 or 2 in which the plasticizer
has a dielectric constant of at least 20.0.
4. A composition as set forth in any of the preceding claims, in which
the plasticizer is selected from cyclic and aromatic sulfones, alkyl
and aryl nitriles, nitro compounds, and alkoxy esters of dibasic
carboxylic acids.
5. A composition as set forth in claim 4 in which the plasticizer is
dimethylsulfolane, ss,2-oxydipropionitrile, octadecylnitrile,
tetramethylene sulfone, or dimethoxyethoxyethyl adipate.
6. The method of forming a conductive rubber composition which
comprises mixing a polar synthetic elastomer having a dielectric
constant of at least 5.0, a polar plasticizer having a dielectric
constant of at least 10.0 which is compatible with the elastomer and
an electrolyte which is soluble in the plasticizer.
7. The method set forth in claim 6 in which the composition is

44. vulcanized.
8. A conductive rubber composition substantially as hereinbefore
described.
9. The method of forming a conductive rubber composition substantially
as hereinbefore described particularly with reference to any of
Examples 1 to 9.
* GB784622 (A)
Description: GB784622 (A) ? 1957-10-09
Tetrakisazo dyestuffs and process of making the same
Description of GB784622 (A)
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The EPO does not accept any responsibility for the accuracy of data
and information originating from other authorities than the EPO; in
particular, the EPO does not guarantee that they are complete,
up-to-date or fit for specific purposes.
i 7 w
, 5 >->nY yh,;
PATENT SPECIFICATION
K- 784,622 Date of Application and filing Complete Specification: Aug
9, 1955.
No 22972/55.
Application made in Germany on Aug 25, 1954.
Complete Specification Published: Oct 9, 1957.
Index at acceptance:-Class 2 ( 4), P 2 G( 2 A: 5 A), P 2 H( 5: 10: 20:
21), P( 4 X: 9 A 7 C).
International Classification:-C 09 b.
COMPLETE SPECIFICATION
SPECIFICATI Oi NO 784, 622 The inventor of this invention in the sense
of being the actual deviser thereof within the meaning of Section 16
of the Patents Act, 1949, is Klaus Bocimaann, of Koln-Sta nheimr,

45. C-erstenkamp, 8, Gennany, of German nationality.
THE PATENT OFFICE, 29th October, 1957 DB OO 058/1 ( 8)/3591 100 10/57
R L.
0 Jr In this formula, R stands for hydrogen, alkyl, hydroxy alkyl or
aryl and R 1 and R,, mean a radical of the benzene or naphthalene
series, and R, stands for a radical of the benzene series carrying the
NH-C-NHR-group in II o-position to the azo bridge and the -NHgroup in
p-position to the azo bridge.
The new tetrakisazo dyestuffs can be obtained by coupling diazotized
amino dyestuffs of the benzene or naphthalene series with a 3-amino-
11-phenyl urea of the general formula:
N H 2 NH-C-NHR To wherein R has the same meaning as above and the
benzene nucleus A may be further substituted except for the coupling
position, and converting the aminodisazo dyestuffs thus obtained-e g
by treating them with phosgeneinto their ureas.
The 3-amino-phenyl ureas used as coupling components can be obtained
by reacting 1disulphonic acid are diazotized in usual manner and
coupled with 151 parts of 3-aminophenyl urea in acetic acid solution
The resulting amino-disazo dyestuff is converted into the
corresponding urea by reacting it with phosgene When the amino disazo
dyestuff has completely reacted, the resulting tetrakisazo dyestuff of
the formula:
lHo 35-Oiw 4 K 2}-NN 44 HI-rnt CO _q 03 W NW-C-Nllz o 2 is filtered
and dried It represents a brown powder which is readily soluble in
water The new dyestuff dyes cotton and regenerated cellulose in
orange-red shades of very good fastness to light and very good
dischargeability.
EXAMPLE 2.
357 Parts of 4-amino-azo-benzene-3,41-sulphonic acid are diazotized as
described in Example 1 and then combined with 195 parts of N ( 3
amrnino)- 11 phenyl-Nl-hydroxyethyl urea The formed amino cdisazo
dyestuff is converted into its urea with phosgene After 1 c, I-,O,,,
9, PATENT SPECIFICATION
784,622 d Date of Application and filing Complete Specification: Aug
9, 1955.
No 22972/55.
Application made in Germany on Aug 25, 1954.
Complete Specification Published: Oct 9, 1957.
Index at acceptance:-Class 2 ( 4), P 2 G( 2 A: 5 A), P 2 H( 5: 10: 20:
21), P( 4 X: 9 A 7 C).
International Classification:-CO 9 b.
COMPLETE SPECIFICATION
Tetrakisazo Dyestuffs and process of making the same We,
FARBENFABRIKEN BAYER AKTIENGESELLSCHAFT, a body corporate organised

46. under the laws of Germany, of Leverlkusen, Germany, do hereby declare
the invention, for which we pray that a patent may be granted to us
and the method by which it is to be performed, to be particularly
described in and by the following statement:-
The present invention relates to tetrakisazo dyestuffs and to a
process of making the same; more particularly, it relates to dyestuffs
corresponding to the general formula:
Ro-N-N-R 2-N-N-R 3 -NH-1 CO L fl N -C-N Hr12 a -12 In this formula, R
stands for hydrogen, alkyl, hydroxy alkyl or aryl and R 1 and R 2 mean
a radical of the benzene or naphthalene series, and R, stands for a
radical of the benzene series carrying the NH-C-NHR group in 0
o-position to the azo bridge and the -NIHgroup in p-position to the
azo bridge.
The new tetrakisazo dyestuffs can be obtained by coupling diazotized
amino dyestuffs of the benzene or naphthalene series with a 3-amino-
11-phenyl urea of the general formula:
>-IH 2 NH-C-NHR II wherein R has the same meaning as above and the
benzene nucleus A may be further substimtuted except for the coupling
position, and converting the aminodisazo dyestuffs thus obtained e g
by treating them with phosgeneinto their ureas.
The 3-amino-phenyl ureas used as coupling components can be obtained
by reacting 1amino 3 acylamino benzene with chloroformic acid phenyl
ester in aqueous acetic 35 solution, treating the urethane thus
obtained with ammonia or an amine in neutral to alkaline medium The
3-acylamino-l-phenyl urea, which is formed while phenol is split off,
is hydrolised in acid solution to form 3-amino 40 1-phenyl urea.
The new tetralisazoi dyestuffs dye cotton and regenerated cellulose
essentially orangered to reddish brown shades of very good fastness to
light and improved dischargeability 45 The following examples
illustrate the invention, the parts being by weight: EXAMPLE 1.
357 Parts of 4-aminoe-azo-benzene-3,41disulphonic acid are diazotized
in usual manner and coupled with 151 parts of 3-aminophenyl urea in
acetic acid solution The resulting amino-disazo dyestuff is converted
into the corresponding urea by reacting it with phosgene When the
amino disazo dyestuff has completely reacted, the resulting
tetrakisazo dyestuff of the formula:
CO o 2 is filtered and dried It represents a brown powder which is
readily soluble in water The 60 new dyestuff dyes cotton and
regenerated cellulose in orange-red shades of very good fastness to
light and very good dischargeability.
EXAMPLE 2.
357 Parts of 4-amino-azo-benzene-3,4 '-sulphonic acid are diazotized
as described in Example 1 and then combined with 195 parts of N ( 3
amino)-1,phenyl-Nl-hydroxyethyl urea The formed amino disazo dyestuff

47. is converted into its urea with phosgene After drying the resulting
azo dyestuff corresponding to the formula:
6,8-disulphonic acid with 107 parts of lamino-3-methylbenzene is
diazotized in usual manner and coupled with 151 parts of 3amino-phenyl
urea in acetic acid solution 45 After converting the amino dyestuff
into the urea with phosgene the tetrakisazo dyestuff of the formula:
H 0.35-0 N=N-4 <N:N-G}NH 503 N NH-C-NN-Ci CH 2-OH 0 is a brownish red
powder which is readily soluble in water; it dyes cotton and
regenerated cellulose in scarlet red shades of very good fastness to
light and good dischargeability.
EXAMPLE 3.
The amino azo dyestuff which can be obtained by coupling 253 parts of
diazotized 1aminobenzene-2,4-disulphonic acid and 121 parts of
1-amino-2,5-dirterhylbenzene is diazotized in usual manner and
combined with 151 parts of 3-amino-phenyl-urea in acetic acid solution
The formed amino disazo dyestuff is converted into the urea with
phosgene.
The dyestuff thus obtained corresponds to the formula:
Ns" 9 "yt H CO f"J-C-NH 2 0-2 is isolated and dried It represents a
brown powder which is readily soluble in water; it dyes cotton and
regenerated cellulose in brown shades of good fastness to light and
good dischargeability.
EXAMPLE 6.
The amino azo dyestuff, obtained by coupling 253 parts of diazotized
1-aminobenzene2,5-disulphonic acid with 121 parts of
1amino-2,5-dimethylbenzene, is diazotized in acetic acid solution and
combined with 165 parts of 3-amino-4-methyl-l-phenyl urea The formed
amino disazo dyestuff is converted into the urea with phosgene After
drying the resulting azo dyestuff of the general formula:
CH 3 HOBS Q-N=N N=fi NH CO 503 H CH 3 RNH-C-NH 1 2 2 _ After drying it
represents a brown powder which is readily soluble in water; it dyes
cotton and regenerated cellulose in red-brown shades of good fastness
to light and good dischargeability.
EXAMPLE 4.
357 Parts of 4-aminoazobenzene-3,4-disulphonic acid are diazotized as
described in Example 1, coupled with 308 parts of N-(
3amino)-l-phenyl-Nl-3-sulphophenyl urea and the formed amino disazo
dyestuff is converted into the urea with phosgene After drying the
resufiting azo dyestuff of the formula:
CO w 355 C> ' C c- 4 "H) CO so 3 II NH-C-Hl _ Sop; -2 represents a
brown powder which is soluble in water; it dyes cotton and regenerated
cellulose in orange-red shades of good fastness to light and good
dischargeabiity.
EXAMPLE 5.

48. The monoazo dyestuff obtained by coupling 303 parts of diazotized
2-amino-naphthaleneCO 65 represents a brown powder which is soluble in
water; it dyes cotton and regenerated cellulose in reddish-brown
shades of good fastness to light and good dischargeability.
EXAMPLE 7.
The amino azo dyestuff which can be obtained by coupling 173 parts of
diazotized 1aminobenzene-3-sulphonic acid and 223 parts of 1
-aminonaphthalene 7 sulphonic acid is diazotized in usual manner and
combined with 165 parts of N-3-aminophenyl-N 1-methylurea in acetic
acid solution The formed amino disazo dyestuff is converted into the
urea with phosgene The dry dyestuff represents a brown powder which is
readily soluble in water; it dyes cotton and regenerated cellulose in
red-brown shades of good fastness to light
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