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* GB786235 (A)
Description: GB786235 (A) ? 1957-11-13
Process for the germicidal treatment of liquids
Description of GB786235 (A)
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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
Process for the germicidal treatment of liquids
I, HoRsT-GUENThER ROTT, a German
National, the sole personally responsible partner in the firm
Schoeller & Co. Elektrotechnische Fabrik, of 115-119, Moerfelder
Landstrasse, Frankfurt am Main-Sued, Germany, do hereby declare the
invention, for which I pray that a patent may be granted to me, and
the method by which it is to be performed, to be particularly
described in and by the following statement:
This invention concerns the germicidal treatment of liquids.
Germicidal treatment of liquids with ultrasonic waves, has already
been proposed.
Thus it is known, for example, to utilise an ultrasonic pipe or
whistle effect to treat a liquid which is allowed to flow at high
speed against an edge, whereby ultrasonic oscillations arise in the
liquid, which is consequently de-germinated. The effect of the sound
at the high flow velocity of the liquid, however, is of such a short
duration that neither a sound dispersion sufficient for degermination
nor of uniform sound distribution in all the parts of the liquid can
reliably be achieved. This process is therefore not wholly effective
in practice.
According to another known process, the liquid is set in motion by
means of a centrifuge, whereby on impingement of the liquid on a fixed
wall, ultrasonic oscillations likewise can arise. In this case also,
however, there is no guarantee that the sound distribution has a
sufficient germicidal action.
Above all, moreover, separation of the degerminated portions of the
liquid from those not de-germinated is not possible in the two
processes described.
It is an object of the invention to provide a process for the
germicidal treatment of liquids with ultrasonic waves by means of
which those portions of the liquid which are to be exposed to
intensive sound radiation are completely separated from the remainder
of the liquid. Exact and continuous control of the degree of sound
intensity having a sufficient germicidal action is thus possible.
The invention makes use of the known phenomenon that liquids which are
exposed to a strong ultrasonic effect are converted far below their
boiling point into mist, which escapes from the liquid.
According to the present invention, therefore, the liquid is atomised
ultrasonically, the resulting mist is conducted away and is then
condensed.
Only that part of the liquid is atomised which is exposed to a maximum

sound intensity. With a sufficient value of sound intensity only
fragments of bacteria pass into the mist, but no living bacteria. The
minimum value of the intensity for atomisation of the liquid in the
ultrasonic field to begin is dependent upon the specific gravity of
the liquid, its viscosity and its vapour pressure. The said minimum
value for atomisation can thus be increased by producing an excess
pressure above the surface of the liquid.
The process proposed by the invention is of especial importance in the
germicidal treatment of liquids for therapeutic purposes.
What I claim is : -
1. A process for the germicidal treatment of liquids characterised in
that a liquid is atomised ultrasonically, and that the resulting mist
is conducted away and is then condensed.
2. A process as claimed in claim 1, in which the pressure above the
surface of the liquid is above atmospheric pressure.
* GB786236 (A)
Description: GB786236 (A) ? 1957-11-13
Electric wave-signal modifying apparatus
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US2890273 (A)
US2890273 (A) less
PATENT SPECIFICATION
786,236 Date of Application and filing Complete Specification: Dec 5,
1955.
No 34806/55.
Application made in United States of America on Dec 14, 1954.
Complete Specification Published: Nov 13, 1957.
Index at Acceptance:-Casses 40 ( 3), F 3 B; and 40 ( 5), L 14 E, L 15
G( 3: 5).
International C Lssification:-H 1 OH 3 c H 04 j, w.
Electric wave-signal modifying apparatus We, HAZEL Ti NE CORPORATION,
a corporation organized and existing under the laws of the State of
Delaware, United States of America, of 59-25 Little Neck Parkway,
Little Neck 62, New York, 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: -
General.
The present invention is directed to electric wave-signal modifying
apparatus for converting a wave signal which is double side-band

modulated at one phase by one component and at least partially single
sideband modulated at another phase by another component into a wave
signal which is double side-band modulated by both components More
specifically, the present invention is directed to modifying an NTSC
type of color subcarrier wave signal modulated by a double side-band Q
component and a partially single side-band I component into a
-subcarrier wave signal double side-band modulated by both the I and Q
components.
In the form of color-television system now standard in the United
States, hereinafter referred to as the NTSC color-television system,
information representative of a scene in color being televised is
utilized to develop at the transmitter two substantially simultaneous
signals, one of which is primarily representative of the luminance and
the other representative of the chrominance of the image To develop
the latter signals, the scene being televised is viewed by one or more
television cameras which develop, for example, color signals G, R, and
B individually representative, respectively, of the primary colors
green, red, and blue of the scene The signals G, R, and B are combined
in specific proportions to develop a signal Y representative of the
luminance of fpr Jv -' the televised image Additionally, in one form
of NTSC color-television system, the signals R and B are modified to
color-difference signals R-Y and B-Y and these colordifference signals
are utilized individually to 50 modulate quadrature phases of a
subcarrier wave signal having a mean frequency within the
video-frequency pass band The modulated subcarrier wave signal
represents chrominance, that is, it represents the saturation 55 and
hue of the televised image At a receiver in the NTSC system, the
luminance and chrominance signals are detected and the hue and color
saturation information is derived from the chrominance signal and 60
combined with the luminance signal to develop the three color signals
G, R, and B which are utilized to reproduce the televised color image.
Preferably, both of the color-difference 65 signals should be
translated as double sideband modulation of the subcarrier wave signal
However, double side-band transmission undesirably limits the band
widths of the color-difference signals For example, 70 for a
subcarrier wave signal of approximately 3 6 megacycles translated
through video-frequency channels having pass bands of approximately
0-4 2 megacycles, the band widths of the modulating color-difference
75 signals would be limited to approximately 0.6 megacycle if these
signals are to be transmitted, as double side-band modulation of the
subcarrier wave signal The band widths of the color-difference signals
that are 80 utilized cannot be arbitrarily limited since they have to
be sufficiently wide to provide adequate chrominance information in
the reproduced image and are, therefore, at least to some degree
determined by the sensitivity 85 of the human eye to saturation
changes in colors represented by the different ones of the
color-difference signals Experience has indicated that the eye is less
sensitive to saturation changes in colors along a green 90
white-magenta axis of a conventional colordiagram Information of
approximately 0-.5 megacycle with respect to colors along such color
axis appears to satisfy the response of the human eye to such colors
Consequently, in an NTSC type of system a signal representative of
colors along such axis and designated the Q signal is transmitted with
a band width of approximately 0 5 megacycle so as to effect double
side-band modulation of the subcarrier signal Having selected such Q
signal, in order to provide chrominance information for the gamut of
primary colors, a signal I representative of changes along another
color axis orangewhite-cyan is also developed at the transmitter and
utilized to modulate another phase of the subcarrier wave signal
However, since the eye is more sensitive to changes along the latter
color axis, the I signal requires a band width of approximately 1 5
megacycles Consequently, the I signal is transmitted partially as
double side-band modulation and partially as single side-band
modulation of the subcarrier signal Nevertheless, by transmitting the

Q signal only as double side-band modulation of the subcarrier signal
and only the I signal as partially single side-band modulation of such
wave signal the tendency for cross talk between derived I and Q
signals is minimized.
Though benefits are derived by utilizing I and Q modulation signals
and deriving such at the receiver, due to the primary colors
conventionally employed in the picture tube at the receiver, the
derived I and Q signals may not be directly applied to this tube.
At present, the I and Q signals are matrixed to develop the G, R, and
B color signals.
The requirement for such additional matrixing at the receiver to
obtain the benefits of transmitting I and Q signals is undesirable at
least for economic reasons It would be preferable to derive the red,
green, and blue color-difference signals directly while still
obtaining the benefits of the narrow band Q and wideband I signals The
present invention is directed to subcarrier wave-signal modifying
apparatus for modifying the received subcarrier wave signals to permit
direct derivation of the green, red, blue, or any other color
components.
It is, therefore, an object of the present invention to provide a new
and improved electric wave-signal modifying apparatus for use in the
color-signal deriving apparatus of a television receiver.
It is also an object of the invention to provide an electric
wave-signal modifying apparatus for modifying the modulation
components of a color subcarrier wave signal.
It is a further object of the invention to provide an electric
wave-signal modifying apparatus for use in a color-signal deriving
apparatus of a color-television receiver which is effective to
simplify such apparatus and minimize the number of circuit elements
required therein.
In accordance with the present invention, 70 there is provided an
electric wave-signal modifying apparatus comprising a circuit for
supplying a wave signal double sideband modulated at one phase by one
component and at least partially single side-band 75 modulated at
another phase by another component Such apparatus includes circuit
means coupled to the supply circuit for translating the supplied wave
signal with a band width including at least the double side 80 band
portion of the said one component.
In addition, such apparatus includes signalmodifying circuit means
coupled to this signal-translating circuit means and the aforesaid
supply circuit and responsive to 85 the single side-band portion of
the wave signal and substantially unresponsive to the double side-band
portion of the wave signal for developing the complementary side band
of the single side-band portion of the wave 90 signal and for
modifying the wave signal into a resultant wave signal double
side-band modulated by the one and other components.
For a better understanding of the present invention, together with
other and further 95 objects thereof, reference is had to the
following description taken in connection with the accompanying
drawings, and its scope will be pointed out in the appended claims 100
Referring to the drawings:
Fig 1 is a circuit diagram of a color-television receiver having an
electric wave-signal modifying apparatus in accordance with the
present invention, 105 Fig 2 is a group of spectrum diagrams useful in
explaining the operation of the modifying apparatus of Fig 1; Pig 3 is
a circuit diagram of a modified form of a portion of the modifying
appara 110 tus of Fig 1; Fig 4 is a circuit diagram of an additional
modified form of a portion of the modifying apparatus of Fig 1; Fig 5
is a spectrum diagram useful in 115 explaining the operation of the
modifying apparatus of Fig 4; and Figs 6 a-6 d, inclusive, and 7 a-7
d, inclusive, are spectrum and vector diagrams also useful in
explaining the operation of the 120 modifying apparatus of Fig 4.
General Description of Receiver of Fig 1.
Referring now to Fig 1 of the drawings, there is represented a

color-television receiver of a type suitable for utilizing the 125
standard NTSC color-television signal The receiver includes a
video-frequency signal source 10 having an input circuit coupled to an
antenna system 11 It will be understood that the unit 10 may include a
con 130 786,236 786,236 3 ventional source of a video-frequency signal
of the-NTSC type, for example, may comprise the initial stages of a
color-television receiver including one or more stages of
radio-frequency signal amplification, an oscillator-modulator, one or
more stages of intermediate-frequency amplification, and a detector
for deriving the video-frequency signal Such detector stage may also
include 3 ( O an automatic-gain-control circuit Coupled to one output
circuit of the video-frequency signal source, in cascade in the order
named, is a wave-signal modifying apparatus 15, in accordance with the
present invention and to be considered more fully hereinafter, a
synchronous detection apparatus 16, a matrix apparatus 17, and an
image-reproducing device 14 Different input circuits of the apparatus
16 are individually coupled through a phase-modifying circuit 19 and
directly to an output circuit of a referencesignal generator 18 in the
apparatus 15.
Coupled between another output circuit of the source 10 and the
cathode circuit of the :25 device 14, in cascade in the order named,
are a delay line 12 and a luminance-signal amplifier 13 The delay line
12 may be of conventional construction for equating the signal delay
through the units 12 and 13 to that through the units 15, 16, and 17
The luminance-signal amplifier 13 is a conventional wide band
amplifier for translating signals having a maximum band width of
approximately 0-4 2 megacycles The band width of the amplifier 13 may
be limited to an upper frequency less than 4 2 megacycles if it is
desired that no signal components having the frequency of the
subcarrier wave signal be translated therethrough The
image-reproducing device 14 is conventional and may, for example,
comprise a single cathode-ray tube having a plurality of cathodes and
a plurality of control electrodes, different pairs of the cathode and
controlelectrode circuits being individually responsive to different
color signals, as will be explained more fully hereinafter, and
including an arrangement for directing the beams emitted from the
cathodes individually onto different phosphors for developing
different primary colors such as red, green, and blue.
Such a tube is more fully described in an article entitled " General
Description of
Receivers for the Dot-Sequential Color Television System which Employ
DirectView Tri-Color Kinescopes" in the RCA Review for June, 1950 at
pages 228-232, inclusive It should be understood that other suitable
types of color-television imagereproducing devices may be employed The
synchronous detection apparatus 16 may also be of a conventional type
widely used in NTSC type receivers for deriving, for example, the R-Y
and B-Y color-difference signals The matrix apparatus 17 may also be
conventional for combining the derived R-Y and B-Y color-difference
signals into a G-Y color-difference signal.
Another output circuit of source 10 is coupled through a
synchronizing-signal 70 separator 20 to a line-scanning generator 21
and a field-scanning generator 22, output circuits of the latter units
being coupled, respectively, to line-deflection and fielddeflection
windings of the image-reproduc 75 ing device 14 An output circuit of
the linescanning generator 21, for example, a terminal on the
conventional horizontal output transformer therein is coupled to an
automatic-phase-control (APC) system 23 in the 80 apparatus 15 for
purposes to be considered more fully hereinafter A sound-signal
reproducing apparatus 24 is also coupled to the video-frequency signal
source 10 and may include stages of intermediate-frequency 85
amplification, a sound-signal detector, stages of audio-frequency
amplification, and a sound-reproducing device.
It will be understood that the various units and circuit elements thus
far described, 90 with the exception of the wave-signal modifying

apparatus 15, may be of any conventional construction and design, the
details of such units and circuit elements being well known in the art
and requiring no further 95 description.
General Operation of Receiver of Fig 1.
Considering briefly now the operation of the receiver of Fig I as a
whole, an NTSC type of television wave signal is intercepted 100 by
the antenna system 11, selected, amplified, converted to an
intermediate-frequency signal, and the latter signal further amplified
in the unit 10, the video-frequency modulation components thereof
being derived and 105 developed in an output circuit of the unit 10.
These video-frequency modulation components comprise synchronizing
components, the aforementioned modulated subcarrier wave signal or
chrominance signal including a 110 color burst synchronizing signal,
and a luminance or brightness signal The luminance or brightness
signal is translated through the delay line 12, amplified in the unit
13, and applied to the cathodes of the image-repro 115 ducing device
14 The modulated subcarrier wave signal or chrominance signal is
translated through the apparatus 15, wherein it is modified in a
manner to be considered more fully hereinafter, and 120 applied to an
input circuit of the synchronous detection apparatus 16 The apparatus
16 includes at least a pair of synchronous detectors individually
responsive to different ones of the reference signals either
translated 125 directly from the generator 18 or through the
phase-modifying circuit 19 for deriving from the applied chrominance
signal modulation components, for example, the R-Y and B-Y modulation
components thereof 130 786,236 The derived R-Y and B-Y modulation
components are matrixed in the apparatus 17 in a conventional manner
to develop the color-difference signal G-Y The three color-difference
signals are individually applied to different ones of the control
electrodes in the image-reproducing device 14.
The line-frequency and field-frequency synchronizing signals are
separated from the video-frequency components and from each other in
the synchronizing-signal separator The separated signals are applied
to the generators 21 and 22 to synchronize the operation thereof with
the operation of corresponding units at the transmitter.
These generators supply signals of sawtooth wave form which are
properly synchronized with respect to the transmitted signal and are
individually applied to the line-deflection and field-deflection
windings of the image-reproducing device 14 to effect a rectilinear
scanning of the screen in such device The color-difference signals
B-Y, G-Y, and R-Y combine with the luminance signal -Y in the electron
guns of the device 14 effectively to develop color signals B, G, and R
which intensity-modulate the cathode-ray beams emitted from the
different guns Such intensity modulation of these beams together with
the raster scanning results in an excitation of the different color
phosphors on the image screen to effect reproduction of the televised
color image.
The sound-signal modulated wave signal accompanying the television
signal is selected, amplified in the source 10, and applied to the
sound-signal reproducing apparatus 24 as an intermediate-frequency
signal It is further amplified in the apparatus 24, detected, and
utilized to reproduce sound in a conventional manner.
Description of Wave-Signal Modifying
Apparatus of Fig 1.
Considering now the wave-signal modifying apparatus 15 of Fig 1, such
apparatus includes a circuit for supplying a wave signal double
side-band modulated at one phase by one component and at least
partially single side-band modulated at another phase by another
component Such supply circuit is the chrominance-signal amplifier 26
preferably having a pass band of approximately 2 1-4 2 megacycles An
output circuit of the amplifier 26 is coupled through the
automatic-phase-control system 23 to the generator 18 for controlling
the phase of the signal developed therein.
The apparatus 15 also includes one channel coupled to the amplifier 26

for translating the wave signal supplied by the unit 26 with a band
width including at least the double side-band portion of the
aforementioned one modulation component More specifically, the one
channel includes, in cascade in the order named, a filter network 27
having a pass band of 3 1-4 1 megacycles and a buffer amplifier 28
coupled between the output circuit of the amplifier 26 and an adder
circuit 29 The network 27, the amplifier 28, and the adder circuit 29
may be 70 of conventional construction and may be designed to have a
total signal delay time equal to that for a modifying circuit now to
be considered.
The modifying apparatus 15 also includes 75 a signal-modifying circuit
coupled to the signal-translating channel just described and to the
output circuit of the amplifier 26.
More specifically, the signal-modifying circuit includes, in the order
named, a filter 80 network 30 having a pass band of 2 1-3 1
megacycles, a synchronous demodulator 31, a filter network 32 having a
pass band of 0.5-1 5 megacycles, and a balanced modulator 33 coupled
between the output circuit 85 of the amplifier 26 and another input
circuit of the adder circuit 29 The synchronous demodulator 31 is a
periodically conductive device responsive to the single side-band
portion of the wave signal translated 90 through the network 30 and
substantially unresponsive to the double side-band portion of the wave
signal blocked by the network 30 The synchronous demodulator 31 may be
a conventional device for deriv 95 ing a portion of the modulation
component at a predetermined phase, specifically at the phase of
modulation of the I signal, of the subcarrier wave signal translated
through the network 30 The balanced modulator 33 100 may be a
conventional modulator for effecting modulation of a wave signal
applied thereto by means of the low-frequency signal translated
through the network 32.
Finally, the wave-signal modifying appara 105 tus comprises means for
controlling the conductivity of the periodically conductive device in
synchronism with one of the modulation phases for causing the
signalmodifying circuit to develop the comple 110 mentary side band of
the aforementioned single side band and to modify the wave signal
developed in the output circuit of the chrominance-signal amplifier 26
into a lresultant wave signal double side-band 115 modulated by both
modulation components of the wave signal More specifically, such
control means comprises the reference-signal generator 18 having an
output circuit coupled through a phase-modifying circuit 120 34 to an
input circuit of the demodulator 31 and through the unit 34 and an
additional phase-modifying circuit 39 to an input circuit of the
balanced modulator 33 The phase and frequency of the signal developed
125 by the generator 18 are controlled by the APC system 23, in
response to a color burst synchronizing signal applied to the system
23 by the amplifier 26, to have a specific relation to the modulated
subcarrier wave 130 786,236 786,236 S signal amplified by the unit 26
The frequencies of -the subcarrier wave signal and the signal
developed by the generator 18 are maintained equal and the phase
relation is so maintained that the signal directly applied to the
apparatus 16 from the generator 18 is in phase with the modulation
phase of the subcarrier wave signal of one of the signals to be
derived in the apparatus 16 For example, the phase of the signal
directly applied from the generator 18 is in phase with the modulation
phase of the R-Y color-difference signal In such case, the design of
the phase-modifying circuit 19 is such as to delay the phase of the
signal developed in the output circuit of the generator 18 under
consideration so that in another detector in the apparatus 16 such
delayed signal is in phase with the modulation phase of the B-Y
color-difference signal.
The phase-modifying circuit 34 controls the phase of the signal
translated therethrough so that such phase occurs in coincidence with
that phase of the applied chrominance signal at which the I-modulation
component occurs and thereby causes the demodulator 31 to be

conductive in synchronism with the I-modulation phase The circuit 39
controls the phase of the reference signal translated therethrough so
that the I-modulated signal developed in the output circuit of the
modulator 33 and applied to the adder circuit 29 is in phase with the
I-modulation phase of the signal translated through the units 27 and
28 and also applied to the adder circuit 29.
Operation of Wave-Signal Modifying Apparatus of Fig 1.
Considering now the operation of the signal-modifying apparatus 15 of
Fig 1, a chrominance signal, specifically the modulated subcarrier
wave signal and its side bands extending over the range of 2 1-4 1
megacycles, is translated through the amplifier 26 Such subcarrier
wave signal with its side bands is diagrammatically represented by
Curve A of Fig 2 and has a mean frequency of approximately 3 6
megacycles, a double side-band region between 3 1 and 4 1 megacycles,
and a single side-band region between 2 1 and 3 1 megacycles.
The double side-band region includes the modulation components I and Q
at quadrature phases of the subcarrier wave signal and these
components are translated through the network 27 and the buffer
amplifier 28 and applied to an input circuit of the adder circuit 29
Such translated double side-band component is represented by Curve B
of Fig 2 The single side-band component, represented by Curve C of Fig
2, is translated through the network 30 and applied to an input
circuit of the synchronous demodulator 31 A sine-wave signal having
the same frequency as the subcarrier wave 65 signal, that is, a
frequency of approximately 3.6 megacycles and in phase with the
Isignal modulation phase of the modulated subcarrier wave signal is
also applied to an input circuit of the synchronous demodulator 70 31
The pair of applied signals heterodyne in the demodulator 31 to
develop a beatfrequency signal having a band width of 0.5-1 5
megacycles and representative of that portion of the I signal which
effects single 75 side-band modulation of the subcarrier wave signal
The derived component, represented by Curve D Qf Fig 2, is translated
through the network 32 and applied to an input circuit of the balanced
modulator 33 The 80 signal in the output circuit of the phasemodifying
circuit 39 is applied to the other input circuit of the balanced
modulator 33.
The derived I-signal component, represented by Curve D of Fig 2,
modulates the 3 6 85 megacycle signal applied to the modulator 33 to
develop a pair of side-band components such as represented by Curve E
of Fig 2 The 3 6 megacycle reference signal modulated in the unit 33
is controlled by 90 the phase-modifying circuit 39 to be in phase with
the I-modulation component of the signal translated through the units
27 and 28 Consequently, in the adder circuit 29 the signal developed
in the output circuit 95 of the modulator 33, and represented by Curve
E of Fig 2, combines with the signal translated through the units 27
and 28, and represented by Curve B of Fig 2, to develop a resultant
subcarrier wave signal such as 100 represented by Curve F of Fig 2 The
resultant subcarrier wave signal is double side-band modulated by both
the Q and I modulation components Because of such double side-band
modulation, the I and Q 105 signals, or any components defined by
combination of such I and Q signals and derivable from the subcarrier
wave signal, for example, the R-Y and B-Y modulation components, may
be directly derived in the 110 synchronous detection apparatus 16 with
all the double side-band benefits formerly only available by deriving
the I and Q components, that is, such signals may be derived without
causing the suprious effects resulting 115 from the cross-talk
deficiencies of single side-band modulation to be developed.
Description and Explanation of Operation of Wave Signal Modifying
Apparatus of Fig3 120 Though the modifying apparatus 15 of Fig 1 is
effective to permit direct derivation of the R-Y and B-Y or other
color-difference signals directly from the subcarrier wave signal
without intermediate derivation of I 125 and Q color-difference
signals, the apparatus may require more circuit elements and circuit
components than desirable for the benefits obtained The apparatus of

Fig 3 786,236 Srequires -less components to effect the result obtained
in the apparatus 15 of Fig 1.
Since many of the circuit components in the apparatus of Fig 3 are the
same as components in the apparatus of Fig 1, such components are
identified by the same reference numerals.
In the apparatus of Fig 3 the channel for translating the signal with
a band width including at least the double side-band portion of one of
the modulation components includes a band-pass filter network 40
having a pass band of 2 1-4 1 megacycles Such network is effective to
translate not only the 3 1-4 1 double side-band portion of the
modulated sub-carrier wave signal but also the single side-band
portion between the frequencies 2 1 and 3 1 megacycles Additionally,
in the apparatus of Fig 3 the signalmodifying circuit includes a
balanced modulator 42 and a filter network 43 having a pass band of 4
1-5 1 megacycles coupled, in the order named, between the output
circuit of the filter network 30 and an input circuit of the adder
circuit 29 A second harmonic amplifier 41 is coupled between the
output circuit of the phase-modifying circuit 34 and an input circuit
of the balanced modulator 42 The second harmonic amplifier 41 is
effective to develop a signal having approximately a frequency of 7.2
megacycles and in phase with the modulation phase of the I signal on
the subcarrier wave signal translated through the network 30 The
balanced modulator 42 may be a conventional modulator.
In operation, the modifying apparatus of Fig 3 translates the
modulated subcarrier wave signal partially double side-band modulated
and partially single side-band modulated through the network 40 and
the buffer amplifier 28 for application to an input circuit of adder
circuit 29 The upper side band in the region of 4 1-5 1 megacycles
corresponding to the side band in the region of 2 1-3 1 megacycles is
not translated through the units 28 and 40 or prior stages in the
receiver or transmitter due to the upper frequency cutoff
characteristics of the system through which the television signal
including such modulated subcarrier wave signal is conventionally
translated.
The components of the lower side band in the region of 2 1-3 1
megacycles are translated through the network 30 and applied to an
input circuit of the balanced modulator 42 A 7 2 megacycle sine-wave
signal in phase with that modulation phase of the subcarrier wave
signal at which the I signal modulates such wave signal, that is, with
a peak of the second harmonic signal in co-incidence with the
I-modulation phase, is also applied to the modulator 42 The 2 13.1
megacycle component heterodynes with the 72 -megacycle signal in the
modulator 42 to develop a component having the frequency range of 4
1-5 1 megacycles The latter component corresponds to the upper side
band of the 2 1-3 1 megacycle component The 4 1-5 1 megacycle
component 70 is applied to an input circuit of the adder circuit 29
wherein it combines with the subcarrier wave signal applied to the
other input circuit of the adder circuit 29 to develop a resultant
wave signal having double side 75 band modulation for both the I and Q
components This double side-band modulated subcarrier wave signal is
utilized in detection apparatus such as the unit 16 in Fig 1 in the
manner previously described herein 80 Though the above apparatus has
been described as utilizing a balanced modulator 42, an unbalanced
modulator may be employed if only components having the double
sideband frequencies of 3 1-4 1 megacycles are 85 translated through
the units 40 and 28 and the single side-band components in the range
of 2 1-3 1 megacycles are translated through the units 30, 42, and 43
by modifying the pass band of network 43 to cover at least 90 the
ranges of 2 1-3 1 and 4 1-5 1 megacycles.
Description and Explanation of Operation of Wave-Signal Modifying
Apparatus of Fig 4.
Though the apparatus of Fig 3 requires 95 less circuit components than
that of Fig 1 to effect the same result, it may sometimes be
beneficial to utilize a wave-signal modifying apparatus requiring even

less circuit components than those described with reference 100 to Fig
3 The apparatus of Fig 4 employs a minimum of circuit components for
modification of the subcarrier wave signal from one partially single
side-band modulated to one including only double side-band modu 105
lation Those circuit components in the apparatus of Fig 4 which are
identical with components in the apparatus of Fig 1 are indicated by
the same reference numerals as used in Fig1 110 Referring now to the
apparatus of Fig 4, the channel for translating the wave signal with a
band width including at least the double side-band portion of one of
the modulation components comprises a delay 115 line 52 The delay line
52 is in parallel circuit with a pair of inductively coupled tuned
circuits 51 and 53 having a pair of terminals thereof coupled by means
of the delay line 52 The terminal of the tuned 120 circuit 51 remote
from the delay line 52 is connected to an output circuit of the
chrominance-signal amplifier 26 through a condenser 50 while a center
tap of the tuned circuit 53 is coupled to detection apparatus 125 such
as the unit 16 of Fig 1 The circuits 51 and 53 are broadly resonant at
the mean frequency of the subcarrier wave signal to have a pass band
for the coupled circuits -786; 236 megacycles is applied through the
condenser to the resonant circuit 51 and through the circuit 51 to the
input circuit of the delay line 52 Such applied subcarrier wave signal
is translated through the delay line 52 70 with some delay to develop
across the output circuit thereof a subcarrier wave signal
corresponding to the applied subcarrier wave signal delayed by a
specific amount The subcarrier wave signal applied to the reson 75 ant
circuit 51 is applied to the resonant circuit 53 to induce in the
latter resonant circuit a subcarrier modulated wave signal effectively
having frequencies over the range of 3.1-4 1 megacycles and inverted
in-phase 80 with respect to the signal developed in the output circuit
of the delay line 52 Consequently, the subcarrier wave signal
developed between the anode of the tube 54 and ground effectively has
no frequency components in 85 the range of 3 1-4 1 megacycles, having
only components in the range of 2 1-3 1 megacycles such as represented
by Curve C of Fig 5 At the tap on the inductor of the resonant circuit
53, since this tap with res 90 pect to either end terminal of the
resonant circuit 53 has less impedance than the circuit 53 and
therefore less than the output impedance of the delay line 52, the
inverse signal is not of sufficient magnitude to effect 95 complete
cancellation of the signal developed at the output circuit of the
delay line 52.
Consequently, at such tap a signal is developed such as represented by
Curve C of Fig 5 but having components in the fre 100 quency range of
3 1-4 1 megacycles such as represented by Curve C' of Fig 5.
The manner in which a subcarrier wave signal, having a
frequency-amplitude characteristic such as represented by Curve C of
105 Fig 5, is developed in the resonant circuit 53 has just been
described To understand how a periodically conductive diode, such as
diode 54 conductive in-phase with the Q axis of the subcarrier wave
signal, operates 110 to develop a resultant subcarrier wave signal
double side-band modulated by both the Iand Q-modulation components,
it is initially helpful to consider some of the characteristics of a
single side-band component such 115 as the I component in the range of
2 1-3 1 megacycles A reasonably thorough consideration of single
side-band transmission has been presented in an article entitled
"Effect of the Quadrature Component in 120 Single Side Band
Transmission" at pages 63-73, inclusive, of The Bell System Technical
Journal for 1940 This article supports the proposition that the power
or energy of a single side-band component -is distributed 125
substantially equally in quadrature components, that is, in
amplitude-modulation and phase-modulation of the carrier wave signal
resulting in the amplitude-phase ambiguity attributed to single
side-band tranis 130 of approximately 3 1-4 1 megacycles, that is, a
pass band equivalent to the double sideband portion of the subcarrier
wave signal.

The coupled tuned circuits 51 and 53 have an over-all phase delay
inherent in such circuits and the delay of the delay line 52 is made
equal to that of circuits 51 and 53.
In order to provide a load circuit for the 4.1-5 1 megacycle
components to be developed, the delay line 52 is designed to have a
pass band of 2 1-5 1 megacycles, though signals having only the
frequency range of 2.1-4 1 megacycles are translated therethrough from
the output circuit of the amplifier 26 The impedances of the circuits
51 and 53 and the terminating impedances of the delay line 52 may be
made equal for convenience The pass band of the delay line 52 is
represented by Curve A of Fig 5 while that of the coupled tuned
circuits 51, 53 is represented by Curve B of Fig 5 The phase
translation characteristic of the coupled circuits 51 and 53 is the
inverse of that for the delay line 52 Consequently, signals developed
in the output circuit of the delay line 52 which correspond to the
signals developed in the tuned circuit 53 are equal and opposite in
magnitude Such correspondence occurs over the band of frequencies 3
1-4 1 megacycles Therefore, the over-all pass band of the system
including the units 51, 52, and 53 is such as represented by Curve C
of Fig 5.
The signal-modifying circuit of Fig 4 includes a diode 54 having the
anode thereof coupled to the tuned circuit 53 and the cathode coupled
in series through a tuned circuit 56 and a biasing circuit 57 to
ground.
The circuit 56 is resonant at the second harmonic frequency of the
subcarrier wave signal, that is, at approximately 7 2 megacycles An
output circuit of the referencesignal generator is coupled through a
phasemodifying circuit 58 and a second harmonic amplifier 59 to a
resonant circuit 55 tuned to approximately 7 2 megacycles and which is
inductively coupled to the resonant circuit 56 The phase-modifying
circuit 58 is arranged to delay the phase of the signal developed in
the generator 18 so that the 7.2 megacycle signal in the cathode
circuit of the diode 54 is in phase with the phase of the subcarrier
wave signal at which the Q-modulation component occurs The biasing
circuit 57 develops a positive potential during conduction periods of
the diode 54 which tends to maintain the diode nonconductive The
potential of the 7 2 megacycle signal is such as to render the diode
54 conductive at the times of the negative peaks thereof damping any
signal then being applied to the anode of the diode 54.
Considering now the operation of the apparatus of Fig 4, the
subcarrier wave signal modulated over the range of 2 1-4 1 786,236
mission Effectively a single side-band component can be considered to
have two sets of side bands, one being in-phase and the other in
quadrature-phase with the carrier wave signal This relationship is
represented by the spectrum diagrams of Figs 6 a-6 d, inclusive, and
the related vector diagrams of Figs 7 a-7 d, inclusive, representing
the I single side-band component in the frequency region of 2 1-3 1
megacycles The reference axis in the vector -diagrams of Figs 7 a-7 d,
inclusive, is that phase of the subearrier wave signal at which the I
signal should effect amplitude-modulation.
In Fig 6 a, the relationship in frequency and amplitude of the single
side-band component to the subcarrier wave signal is represented and
Fig 7 a is a vector representation of the magnitude and phase of such
single side-band I component Without disturbing the validity of
representation, the single side-band component represented by Figs 6 a
and 7 a may be represented as including an upper side-band component
of equal energy half of which is in a positive sense and the other
half in a negative sense so that the two halves cancel each other
leaving only the single side-band component.
Figs 6 b and 7 b represent the single sideband component with the
addition of such upper side-band component It is obvious that in Figs
6 b and 7 b the halves of the added upper side-band component cancel
each other and, therefore, the representations of Figs 6 b and 7 b are
as valid as the representations of Figs 6 a and 7 a However, the

representations of Figs 6 b and 7 b assist materially in indicating
some fundamental aspects of a single side-band component as verified
from experiments described in the article referred to above.
The side-band components represented by Figs 6 b and 7 b are separable
into two sets of equal side-band components One of such sets is
represented by Figs 6 c and 7 c and includes the side-band components
symmetrically disposed about the reference axis and thus these figures
represent sideband components which effect pure amplitude-modulation
of the I-modulation phase of the subcarrier wave signal The other set
of side-band components is represented by Figs 6 d and 7 d and is
symmetrically disposed about an axis in-quadrature with the reference
axis or, more specifically, that axis of the subcarrier wave signal at
which the Q signal effects amplitude-modulation of such subcarrier
wave signal Consequently, the side-band components represented by Figs
6 d and 7 d represent amplitude modulation of the subcarrier wave
signal at the Q axis and thus represent cross talk of the I-modulation
signal into the Q-modulation signal This is the undesirable cross talk
eliminated by means of wave-signal modifying apparatus in accordance
with the present invention.
The signal developed across the diode circuit including the networks
56,57 and the diode 54 has the spectrum represented by 70 Curve C of
Fig 5 unmodified by the portion represented by Curve C' The diode 54
is normally nonconductive due to the bias developed in the network 57
The 7 2 megacycle signal applied by means of the 75 ' resonant circuit
56 to the cathode of the diode 54 is, as has been explained
previously, phased so that the negative peaks thereof are in phase
with the Q-modulation axis of the modulated subcarrier wave signal 80
applied to the anode of the diode Since, as represented by Curve C of
Fig 5, the subcarrier wave signal applied to the diode 54 includes no
Q-modulation components, that is, includes no energy in the region of
85 3.1-4 1 megacycles, the diode 54 cannot respond to components in
this region and, therefore, has no effect on the double sideband Q
components of the subcarrier wave signal However, the applied
subcarrier 9 a wave signal does include components in the region of 2
1-3 1 megacycles, these components representing the single side-band
modulation effected by the I signal The diode 54 is, as has been
described, rendered 95 conductive in phase with the Q-modulation phase
and thus is rendered conductive in phase with the components
represented by Figs 6 d and 7 d Consequently, such components are
effectively shunted to ground by 100 the conducting diode leaving only
those I components which effect amplitude-modulation of the subcarrier
wave signal at the proper phase and which are represented by Figs 6 c
and 7 c Thus, effectively the sub 105 carrier wave signal is modified
to have upper and lower side-band modulation components, such as
represented by Figs 6 c and 7 c, in place of what previously was only
single side-band modulation of the sub 110 carrier wave signal
Consequently, the signal developed at the tap terminal of the resonant
circuit 53 and including I and Q double side-band components for the
region of 3 14.1 megacycles, as represented by Curve C'115 of Fig 5,
and I double side-band components in the regions 2 1-3 1 and 4 1-5 1
megacycles, as represented by Figs 6 c and 7 c, is a subcarrier wave
signal fully double side-band modulated by both the Q and I 120
components This signal is utilized in the detection apparatus, such as
the unit 16 of Fig 1, in the manner previously considered herein The
signal developed at the tap terminal of the resonant circuit 53 is 125
employed to provide a wave signal modulated to equal levels of the I
and Q components This is accomplished because the level of the signal
at the tap terminal is a fraction of that at the delay-line
termination 130 786,236 786,236 9 for the double side-band components
in the frequency range of 3 1-4 1 megacycles, for example, a level of
one-half that at the delay line As indicated by the levels of the
sideband components represented by Fig 6 c, the I-modulated portion of
the subcarrier wave signal, that is the components in the frequency
ranges of 2 1-3 1 and 4 1-5 1 megacycles, are attenuated by the

signalf O modifying process to be approximately onehalf the level of
the I-modulated side-band portion represented by Fig 6 a In order to
retain equality of modulation level, it is desired that the double
side-band modulated portion of the wave signal be similarly
attenuated, that is, the portion in the range of 3 1-4 1 megacycles,
and this is effected by employing the signal at the tap terminal of
the tuned circuit 53 If the output signal is taken from the delay line
only, then the components in the range of 3 1-4 1 megacycles are twice
the intensity of those in the ranges 2 1-3 1 and 4 1-5 1 megacycles
This might be desirable to provide increased gain for the
low-frequency derived components, that is, to provide low-frequency
boost if such is found to be beneficial.
The development of the upper side band of the I component may also be
considered as a heterodyning operation in which the I-signal side-band
components in the range of 2 1-3 1 megacycles are heterodyned with the
7 2 megacycle signal in the cathode circuit of the diode 54 to develop
the 4 1-5 1 megacycle components When so considered, the operation of
the diode 54, conductive in-phase with the Q components, is such as to
damp out the Q components at a 7 2 megacycle rate The shunted Q
components heterodyne with the 7 2 megacycle switching of the diode to
develop an upper side-band component.
Though there have been described herein circuits for converting a
subcarrier wave signal at least partially single side-band modulated
to another subcarrier wave signal entirely double side-band modulated
and from which R-Y and B-Y modulation components may be directly
derived with all the benefits of initially deriving I and Q
components, it should be understood that the invention is broadly
directed to the conversion of one type of wave signal to another and
not to the conversion of a specific wave signal to a specific other
wave signal for the purpose solely of deriving the specific modulation
components described herein The resultant wave signal double side-band
modulated may be utilized in any 460 manner desirable and any
modulation components may be derived therefrom, such as the
color-difference signals described herein or others, and such
components will effectively have the benefits of double side-band s 65
modulation and be free from the deficiencies and limitations of single
side-band modulation Additionally, though the description herein has
been directed to utilization of the invention with three-gun picture
tubes, modifying apparatus in accordance with the present invention
also has extensive utility in single-gun picture tubes where the color
detection occurs within the picture tube.
Such signal-modifying apparatus operates in a manner analogous to that
previously described to develop the complementary side band of the
single side band and to modify the wave signal into a resultant double
sideband wave signal This signal-modifying apparatus may be employed
in addition to apparatus which modifies the subcarrier and luminance
signal to the form required for one-gun tubes.
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* GB786237 (A)
Description: GB786237 (A) ? 1957-11-13

Process for the preparation of hydrogen peroxide
BE543261 (A) DE1025396 (B) FR1137161 (A) US2904478 (A)
BE543261 (A) DE1025396 (B) FR1137161 (A) US2904478 (A) less
AMENDED SPECIFICATION
Reprinted as amended in accordance with the Decision of the
Superintending Examiner acting for the Comptroller-General, dated the
eighteenth day of October, 1960, under Section 33, of the Patents Act,
1949.
PATENT SPECIFICATION
DRAWINGS ATTACHED Date of Application and filing Complete
Specification: Dec 6, 1955.
So | r No 34886/55.
Application made in Germany on Dec 8, 1954.
Index at acceptance:-Class 1 ( 2), A 7.
International Classification:-C Olb.
Process for the preparation of Hydrogen Peroxide We, DEUTSCHE GOLD UND
SILBERSCHEIDENSTALT vormals Roessler, a German Joint Stock Company, of
9, Weissfrauenstrasse, Frankfurt am Main, 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 a process for the preparation of
hydrogen peroxide by the electrolytic oxidation of sulphuric acid or a
sulphate and decomposition of the persulphuric acid or persulphate
formed at the anode.
It is known to prepare hydrogen peroxide by the anodic oxidation of
sulphuric acid or a sulphate hydrolysis of the persulphuric acid or
persulphate so formed and fractional distillation end/or condensation
of the resulting solution of hydrogen peroxide In this process
hydrogen is produced at the cathode and this has hitherto not as a
rule been used, for various reasons, in the technical working of the
electrolytic process.
It is also known that hydrogen peroxide can be obtained from hydrogen
by a number of methods of which the following can be mentioned.
( 1) The catalytic combustion of hydrogen with molecular oxygen.
( 2) The combustion of hydrogen with molecular oxygen by means of a
silent electrical discharge.
( 3) The reaction with hydrogen of an organic compound such as
anthraquinone, or an alkyl derivative thereof such as 2 methyl
anthraquinone, or azotoluene which forms, by such lPrice 3 s 6 d l
reaction, a compound with readily separable hydrogen atoms and
subsequent autoxidation of the latter compound with molecular oxygen.
( 4) Reduction of cadmium hydroxide, anialgamation of the resulting
metallic cadmium with mercury and reaction of the amalgam with water
in the presence of molecular oxygen.
In any of these methods the molecular oxygen may be in the form of

gaseous oxygen itself or of gases containing oxygen, such as air.
By these methods it is possible to obtain hydrogen peroxide only in
dilute solution whose working up is expensive; but it becomes
economical, in an electrolytic process in which hydrogen peroxide is
produced from persulphuric acid or a persulphate at the anode, to work
up such a solution.
According to the present invention, therefore, there is provided a
process for the preparation of aqueous hydrogen peroxide by the
electrolytic oxidation of sulphuric acid or a sulphate and
decomposition of the persulphuric acid or persulphate formed at the
anode in which the hydrogen produced at the cathode is employed for
the preparation of aqueous hydrogen peroxide by a method known per se
and the aqueous hydrogen peroxide produced from the cathode hydrogen
and the persulphuric acid or persulphate solution are treated in a
common process for the working up of the hydrogen peroxide, the
working up being effected by fractional distillation and/or
condensation The combined working up of aqueous solution of hydrogen
peroxide produced from the cathode hydrogen, although this is
comparatively weak in hydrogen per786,237 oxide, and that obtained by
decomposition of the persulphuric acid or a persulphate, gives a
self-contained process giving a good yield of hydrogen peroxide and
high energy efficiency.
It is desirable, in carrying out the process, to recover as completely
as possible and particularly in a pure form, the hydrogen formed on
the cathode, which can readily be done by the process of Specification
No 735,195.
It is particularly important to employ the hydrogen in a high degree
of purity when it is reacted with an organic substance which forms a
compound with readily separable hydrogen atoms Since such compounds,
when treated with molecular oxygen for the production of hydrogen
peroxide are converted again to the starting materials, the latter can
be used cyclically by further reaction with hydrogen.
Similarly, when the hydrogen is used for the reduction of cadmium
hydroxide, the decomposition of the cadmium amalgam which gives rise
to hydrogen peroxide also yields cadmium hydroxide again which can
thus be used cyclically as illustrated by the following equations.
Cd(OH)2 + H 2,-Cd+H 20 Cd + Hg Cd(Hg) Cd(llg) + 2 H 20 + O 2->Cd(OH)2
+ H 202 (+ Hg) A process using the hydrogen from the cathode gives a
hydrogen peroxide solution of lower concentration than that of the
solution obtained by decomposition of the anodically oxidised solution
It is therefore very advantageous to work up such a dilute solution
toaether with the anodically oxidised solution.
The fact that it is no longer necessary to concentrate these more
dilute solutions separately, by means of organic compounds, for
example, means that there is less need to take account of undesired
secondary reactions.
In the working up by distillation of the solution obtained by
decomposition of the anodically oxidised solution, relatively large
quantities of steam become available, since the steam is generally
evolved at a concentration of 7-10 % hydrogen peroxide The heat
content of these large quantities of steam may be utilised in a simple
manner and favourably from the point of view of energy for the
concentration of the dilute peroxide solutions obtained from the
cathodic hydrogen Thus quite dilute solutions may be utilised
effectively by simply adding them as a reflux to vapours from the
solution obtained by decomposition of the anodically oxidised solution
according to a preferred method of carrying out the invention.
EXAMPLE 1
Electrolysis is carried out in a persulphuric acid plant producing
1,000 Kg of hydrogen peroxide of 25 % concentration by weight in 24
hours This plant has a current capacity of 5 x 7000 Amp = 35000 Amp
for the anodic and cathodic current operation According to the process
of Specification No 735,195 electrolysis is effected with a voltage of
4 35 volts per cell and with 70 % overall yield for the anodic process

(current yield x distillation yield), there is a consumption of 10 k-W
direct current for each Kg of 100 % hydrogen peroxide produced.
With the stated quantity of current 14 64 cbm of hydrogen gas per hour
simultaneously produced at the cathodes, of which more than % can be
recovered according to the process of Specification No 735,195.
In the working up by distillation of the anodically produced
persulphuric acid, which, under the above stated conditions, amounts
to approximately 6,500 litres of 32 % H 2520 in 24 hours, a reflux of
about 850 litres occurs during fractional condensation to produce
hydrogen peroxide of 35 % by weight This quantity of liquid which is
condensed from the waste vapour may be replaced by a solution of
hydrogen peroxide obtained from the hydrogen liberated at the cathode,
the hydrogen peroxide content of which is then brought to % by weight
almost without loss or cost.
Moreover the heat of the exhaust steam can be utilised by
pre-concentrating the solution of hydrogen peroxide obtained from the
cathodic hydrogen in a heat exchanger and then adding the solution to
the reflux during the fractionating The condensed exhaust vapours can
then be used for diluting the electrolyte from the anode process after
the distillation.
As already indicated, the cathodic hydrogen may be used to make
hydrogen peroxide by an autoxidation process employing an alkyl
anthrahydroquinone in a suitable solvent The alkyl anthrahydroquinone
which is first formed is oxidised by means of oxygen or
oxygencontaining gases and the alkyl anthraquinone which is recovered
can be re-used.
In the alkyl anthraquinone process approximately 80 cbm of hydrogen
gas are required for 100 Kg 100 % H 202 The persulphuric acid process
of this example yields 14 64 cbm hydrogen gas per hour, of which 95 %
can be utilised This is 13 9 cbm per hour or 334 cbm in 24 hours, so
that about 400 Kg 100 %/ hydrogen peroxide, that is to say, more than
from the anode process, can be obtained The hydrogen peroxide solution
obtained from the alkyl anthraquinone process is worked up in the
distillation process of the anodic product.
If it is considered that the cathodic hydrogen, apart from the costs
of the apparatus to utilise it, is yielded without cost and also a
great part of the heat is available for the concentration of the
solutions, it will be seen that the combined use of the two processes
yields a very cheap process of preparing hydrogen peroxide In addition
it enables the concentration of the hydrogen peroxide solu786,237
roxide obtained from this process is reduced to cadmium metal by the
cathodic hydrogen at temperatures below 3000, and this dissolved in
mercury and can thus be used cyclically.
EXAMPLE 3
This example illustrates the combination of the electrolytic process
with catalytic combustion of hydrogen to form hydrogen peroxide, and
is shown in Fig 2 of the accompanying drawings In Figure 2 the
electrolysers for obtaining persulphuric acid or its salts are
indicated by 21 The cathodically produced hydrogen is collected in the
pipe line 22 and the anodically oxidised solution flows through 23
into the preheating column 24 (in which mainly the hydrolysis and a
part of the distillation is undertaken) and from there into the column
where the formed hydrogen peroxide is expelled by direct steam At the
foot of the column, at 26, the sulphuric acid is drawn off and
returned to the electrolysers through 27 in the cycle The vapour
mixture from the column 25 flows through 28 into the fractionating
condenser 29 whence aqueous hydrogen peroxide is removed at 220 The
steam is condensed at 221 The cathodically produced hydrogen flows
through 22 into the catalyst oven 222 into which air or oxygen is
introduced at 223 The hydrogen peroxide produced is passed together
with water, through the connection 224 at 225 as a reflux, to the
fractionating condenser 29 and enriched there.
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* GB786238 (A)
Description: GB786238 (A) ? 1957-11-13
Improvements in or relating to composite catalysts for use in the hydration
of olefins and to the preparation of alcohols thereby
DE1042561 (B)
DE1042561 (B) less
COMPLETE SPECIFICATION Improvements in or relating to Composite
Catalysts for Use in the Hydration
of Olefins and to the Preparation of Alcohols Thereby.
We, N. V. DE BATAAFSCHE PETROLEUM MAATSCHAPPIJ, a company organised
under the laws of The Netherlands, of 30 Carel van Bylandtlaan, - The
Hague, The Netherlands, 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 the preparation of a composite catalyst for
use - in the preparation of alcohols by the vapour-phase hydration of
olefins.
It is known that olefins can be reacted with water to form alcohols,
the reaction being conducted in the vapour phase at high pressures and
moderately eleyated temperatures, and in the presence of a suitable
catalyst.
U.K. Patent Specification No. 651,275, for example, describes such a
process wherein a composite catalyst comprising a solid porous
siliceous support incompletely saturated with an aqueous solution of
phosphoric acid of specified concentration is employed. This process
although successfully used in commercial operations, has been found to
be not entirely satisfactory, for reasons which are attributable to
the particular composite catalyst hitherto employed.
The requirements for a successful composite catalyst for use in the
hydration of olefins include:
A. The catalyst must actively and selec
tively promote the hydration of olefins to
alcohols without causing concurrent for
mation - of excessive amounts of polymers,

tars and cokes, or malodorous by-products,
such as aldehydes.
B. The catalyst must have a sufficiently
long life with respect to its catalytic
activity.
C. The catalyst must be sufficiently
strong mechanically to withstand crushing
and other forces tending to cause its
attrition during preparation and use.
D. The catalyst must be chemically
stable and inert with respect to the various
reactants and reaction products, as well as
to the materials of construction with which
it comes into contact.
It has been found that the particular
material employed as the carrier-determines the character of the final
composite catalyst
with respect to factors C and D, and deter-
mines to a great extent factors A and B, as
well,
Only relatively few materials have been
found to provide all the above requirements
to a practical degree, and even in these cases
there has been need for improvement. Composite catalysts comprising
silica gel as the
carrier have been found to exhibit high
activity levels with good selectivity, but they shave low mechanical
strength and insufficient
resistance to attritional forces. Qther types
of siliceous materials, various aluminas,
cokes and other forms of carbon have been
employed as the carrier material with varying
degree of success. The most useful of all the
carrier materials heretofore employed have
been found to be certain forms of calcined
diatomaceous earth. -These calcined diato
maceous earths are composed primarily of
silica and/or hydrated silica in the form of
complete or incomplete diatoms skeletons,
the diatom skeletons being cemented or
bound together with clay or clay-like
materials. Catalysts prepared by impregnat
ing these materials with phosphoric acid of
the correct concentration have been found
to have satisfactory activity levels, good
selectivity and high mechanical strength.
However, for several reasons calcined
diatomaceous earth materials of this kind have not proved entirely
satisfactory for use as the carrier material. The clay binding
material contains metallic compounds (primarily iron and aluminium
oxides and/or
silicates) which are quite soluble in phosi phorio acid of the
concentration employed in
olefin hydration catalysts, at the tempera
tures normally employed in effecting such
hydrations. The solubility of these compo
nents of the binding material of the carrier
in the impregnating acid causes several
serious problems during the use of the corre
sponding composite catalysts. First, the
alteration of the chemical composition of the
binding material reduces its effectiveness as
a binder, and seriously impairs the mech
anical strength of the final catalyst. Both the mechanical strength of

the catalyst and
its resistance to abrasion are affected, so that
during operation it tends to disintegrate at
an undesirably rapid rate. This break-down
of the catalyst increases the pressure drop across the catalyst bed
and tends to cause
the gaseous reaction mixture to channel
i.e., the bed tends to plug-up, leaving only
restricted paths through which the gases may
flow. - This reduces the effective area of the
catalyst and the intimacy of contact between
the gases and the catalyst surface; the effi
ciency of the catalyst is lowered accordingly.
A further difficulty encountered is that the
finer particles of the catalyst tend to disperse
in the gaseous reaction mixture and pass with
it from the reactor into subsequent process
equipment. This causes additional loss of
catalyst and necessitates clean-up of the other
equipment. The over-all result is that both
the useful life and the efficiency of the catalyst are reduced at an
undesirably rapid rate.
Secondly, these composite catalysts have a tendency to "bleed" during
use. That is to say, a liquid or semi-liquid material tends
to seep from the catalyst. This seepage material appears to consist
primarily of an aqueous solution of free phosphoric acid containing a
substantial concentration of the phosphates of iron and aluminium. It
tends to flow slowly through the catalyst bed and in part, at least,
out of the reactor. A part of the fine particles produced by
disintegration of the carrier material, together with particles of
carbonaceous material formed by cracking of the olefin, becomes
suspended in the seepage material. The fluidity of the resulting
mixture is markedly dependent upon the temperature of the mixture, so
that even a relatively small drop in the temperature of the mixture
causes it to set to a hard, extremely tenacious solid. Thus, where the
mixture passing through the catalyst bed encounters any "cool" zone,
or where the reactor temperature falls more than a few degrees, the
seepage material - hardens, effectively plugging up the catalyst bed.
The area of plugging often grows since the original plug disturbs the
flow pattern of the gases, extending the area of the cool zone. This
effect likewise reduces the efficiency of the catalyst, increases the
pressure drop across
the catalyst bed and causes channelling of
the gaseous reaction mixture. In many in
stances, plugging of the reactor may become
so severe that it is necessary to shut down the
entire reactor and to replace the catalyst long
before this would normally be required.
The seepage material flowing from the re
actor into the subsequent process equipment
also causes difficulties. For example the
effluent gases from the reactor normally pass
through pipes and valves to a heat exchanger
wherein the product alcohol is condensed.
The temperature in such piping is usually
somewhat below the temperature in the re
actor and the effluent gases are cooled sub
stantially in the heat exchanger. Conse
quently, the seepage material deposits out, coating the inner surfaces
of the piping and
the heat exchanger. At the least, such de
posits increase the pressure drop across such
apparatus, and seriously reduce the heat
transfer coefficient of the heat exchanger. re

quiring frequent cleaning of this equipment:
in many cases, replacement of much of the
process equipment immediately downstream
from the reactor has been found necessary.
A further disadvantage of these composite
catalysts lies in the fact that hydration of the
olefin over such catalysts is accompanied by
the production of substantial amounts of
carbonaceous materials. It is thought that
these materials are formed by the cracking
of the olefin reactant, and further that the
cracking reaction is promoted by the iron
present in the catalyst. Reduction of the iron
content of the carrier would therefore be
highly desirable, provided that this could be
accomplished without concurrent reduction
in the mechanical strength of the carrier.
It has now been discovered that these
difficulties can be overcome by the use of a
composite catalyst prepared by impregnating, with an aqueous solution
of phosphoric acid, a modified porous diatomaceous earth- carrier
material prepared in a particular manner and having a structure unlike
that of any material previously proposed in the art.
According to the present invention a process for the production of a
composite catalyst comprises saturating a porous, inert, diatomaceous
carrier material with a strong aqueous solution of phosphoric acid,
heating the resulting impregnated carrier material in an atmosphere
containing water vapour having a partial pressure which is less than
the partial pressure of water vapour in equilibrium with an aqueous
solution of phosphoric acid at the temperature at which the heating is
effected, digesting the heated carrier material with acidified hot
water having a pH less than about 1, washing the digested
carrier material with hot water, drying the washed carrier material
and impregnating the dried carrier material with an aqueous
solution of phosphoric acid.
This process results in a composite catalyst comprising an aqueous
solution of phosphoric acid supported on a carrier consisting
primarily of a porous diatomaceous material the diatom skeletons of
which are coated with silica gel.
By the use of a composite catalyst prepared in accordance with the
present invention, an olefin may be converted to the corresponding
alcohol at significantly higher initial and average conversion levels
than has been possible heretofore. The formation of malodorous
by-products andjor tarry or carbonaceous materials is substantially
reduced.
Substantially no seepage of metallic phosphates occurs, so that
prolonged on-stream periods without significant reduction- in heat
transfer coefficients of downstream heat exchangers or increase in
pressure drop of subsequent transfer equipment are obtainable.
No significant change in the mechanical strength of the catalysts of
the present invention with prolonged use has been noted.
Throughout this specification, the activity of the catalyst will be
expressed in terms of the mole fraction (per cent.) of olefin
converted to the alcohol per pass. Thus, where the term "catalyst
activity level" or, simply, "activity level" is used, this term
expresses the mole per cent. of olefin converted to alcohol per pass
by the particular catalyst considered.
The carrier material for preparing the catalysts of the present
invention may be any of the various diatomaceous earth materials, by
which term is meant any predominantly siliceous material composed
primarily of the silica and/or hydrated silica skeletons of diatoms
which are bonded together by a claylike binding agent, which materials
may be formed into particles of regular size and shape having high -
mechanical strength.

Typical of these materials are the calcined diatomaceous earths
manufactured by the
Johns-Mansville Corporation and marketed under the trade name
"Celite." ("Celite" is a Registered Trade Mark.) Especially desirable
of this class of materials is the grade designated "Celite VIII,"
which is in the form of small pellets and has the following
composition:
Component Weight Per Cent
Silica 86.1
Iron oxide 2.4
Alumina 7.3
Magnesia 1.2
Sodium oxide + potassium oxide 2.2
Titanium dioxide 0.2
Remainder- 0.6
It is preferred that the carrier material be in granular or pelleted
form, and that the smallest dimension of said granules or pellets be
at least about 1/32 of an inch.
The preferred carrier materials of the composite catalysts of the
present invention have an average pore radius of between about 3500 A
and;about 6500 A and at least 5% of the pores have a radius of less
than about 500 A Ordinarily not more than about 25% but at least about
1% of the total weight of the silica is in the form of silica gel, the
remainder being in the form of complete or incomplete diatom
skeletons. The silica gel usually is present in the form of a
substantially uniform layer which is not thicker than about 1500 A
over the surface of the diatom skeleton structure, - the layer
intimately contacting the major portion of the surface area of said
structure. - Carriers in which the thickness of the silica gel layer
is between about 10 and about 250 , are preferred.
The total porosity of these carriers (measured as the number of cubic
centimetres of distilled water absorbed per gram of the carrier
material at ordinary teinperatures and pressures) is between about 0.6
and about 1.1.
The surface area of these carriers is between about 15 and about 40
square metres per gram.
To prepare a catalyst in accordance with the present invention, the
untreated material is first impregnated to substantial saturation with
an aqueous solution of phosphoric acid containing a high concentration
of the acid.
For this purpose, there is preferably employed any aqueous solution of
phosphoric acid containing at least about 70% by weight of phosphoric
acid, such as the commercially available acid which contains
approximately 85% by weight phosphoric acid. The impregnation of the
carrier may be effected by immersing the carrier material in the acid
for a sufficient time to ensure saturation of the material: a soaking
period of between about 1/2 and 1 hour will usually be sufficient for
this purpose. The impregnated carrier is then freed from excess acid
by allowing it to drain thoroughly.
After draining, the impregnated carrier is heated under carefully
controlled and correlatedconditions of temperature and humidity, to
effect solution of substantially all of the components of the
clay-binding material and to effect solution of a controlled amount of
the siliceous diatom skeletons. The heating may be effected at a
temperature between about 150 C and about 400 C, temperatures between
about 225 C and about 325 C being preferred. Heating is effected in an
atmosphere which contains sufficient water vapour to give a partial
pressure less than the partial pressure of water vapour in equilibrium
with an aqueous solution of phosphoric acid at the heating
temperature. Thus, when the heating is conducted within the
above-specified temperature range the atmosphere in which the heating
is conducted should contain water vapour in an 'amount -such that the
partial pressure of water vapour in that atmosphere lies between about
50 and about 500 millimetres of mercury. It has been found that a

catalyst prepared from a carrier heated within the stated temperature
range in an atmosphere in which the partial pressure of water is
between about 150 and 300 -millimetres of mercury possesses optimum
properties, i.e. such a catalyst promotes the conversion of olefins to
alcohols at consistently high conversion levels, has excellent
mechanical strength and exhibits substantially no seepage of metallic
phosphates. The catalyst prepared according to this procedure contains
but a small amount of iron and aluminium compounds. Usually the iron
content (as iron oxide) is less than about 0.30,0, by weight of the
carrier material, and the aluminium content (as the oxide) is somewhat
less than about 3.0%. The form and location of these compounds in the
carrier material are such that the compounds react with the
impregnating acid slowly or not at all, under the usual operating
conditions.
The concentration and availability of the iron
are such as not to promote cracking of the
olefin so that the amount of carbonaceous
materials produced during olefin hydration
is substantially reduced.
The total pressure within the system dur
ing the heating is not a critical factor in the
production of carriers of optimum characteristics, and atmospheric,
subatmospheric
or superatmospheric pressures are all satisfactory, provided the
required humidity relationships are maintained. Operation at
substantially atmospheric pressure is desirable from a practical
standpoint.
The time required for heating varies more
or less directly with the temperature em
ployed. For example, if the heating is carried out at about 100 C, the
effect of the
phosphoric acid is incomplete, even after
50-60 hours of heating, whereas if the tem
perature is maintained at between about
250"C and about 350 C, heating for between about 2 and 8 hours will
effect the reaction between the carrier and the phosphoric acid to
substantial completion. In one case the heating was conducted. at
300"C and under 200 millimetres of mercury partial pressure of water
for 1 hour and the catalyst activity was about 4.5 units. In
comparison, where the heating was continued for 2 hours, the catalyst
activity rose to about 5.1 units. Fur
ther heating did not improve the catalyst activity significantly. When
the heating.is carried out at lower temperatures, i.e. 150"C to 250 C,
somewhat longer periods of heating -up to about 20 hours-will be
required.
Following heating the impregnated carrier material is digested with a
controlled amount of hot water having a pH less than about 1 and it is
believed that this digestion step has a dual effect of dissolving and
removing-: the metallic phosphates present and also - of
hydrolizing the dissolved silicyl phosphates in a controlled manner.
The precise manner in which the silica gel resulting from hydrolysis
of the silical phosphate is deposited in, upon or around the residual
diatom skeleton structure is not known. The improved characteristics
of the catalysts of the present invention do not appear to be only
those which might be expected to arise from merely dcpositing silica
gel on an inert carrier as by dipping the carrier in a silica sol and
drying: the amount of silica gel deposited and/or its location on the
diatom skeleton structure is such that the pore structure of the
diatomaceous earth material is not significantly changed, yet the
catalysts of the present inInvention exhibit improved characteristics.
Whatever the disposition of the silica gel upon the; diatomaceous
earth structure, the preceding description indicates the steps,
determined empirically to be critical, in the production of the
catalyst carrier material.

The heated carrier material is generally digested at about 100 C with
water having a pH of less than about 1.0 until substantially all of
the metallic phosphates have been reremoved, and substantially all of
the dissolved silicyl phosphates have been hydrolized to silica gel
and deposited on the diatom skeletal structure. For providing the
necessary acidity, there may be employed any strong mineral acid.
Sulphuric acid is preferred for this purpose because of its low
volatility.
The volume ratio of. digestion solution to carrier material is
generally above about 0.75:1. It is preferred in order to minimize the
amount of mineral acid required, yet to obtain substantially complete
removal of the metallic phosphates, that this volume ratio be
maintained between about 1:1 and about 2:1. Volume ratios of below
about 0.75:1 are undesirable since lower water to carrier ratios
promote the formation of thick gelatinous extracts of silica or silica
gel.
The pH of the solution is conveniently maintained within the desired
range by emplaying a digestion solution having an initial pH between
about 0.2 and about 0.5. If the pH is not maintained within the
prescribed limits, the iron and aluminium phosphates tend to hydrolize
and precipitate from the solution, coating the carrier material with a
white crust which is very difficult to remove.
This crust is highly undesirable, since it causes plugging of the
pores of-the carrier material and cementation of the carrier
particles.
The digestion may be effected by immersing the carrier in the
acidified water which is maintained at or slightly below its boiling
point, and allowing the mixture to digest for a sufficient time to
ensure substantially complete solution of the metallic phosphates.
The temperature of the mixture is preferably not below about 85"C, but
it is desirable that vigorous boiling be avoided during the diges
tion, since the mechanical strength of the
carrier material is then at its lowest level
during the course of the pretreatment process,
and vigorous boiling may cause undue attri
tion of the carrier material. It is desirable,
however, that the particles of carrier material
be gently agitated during the digestion pro
cess, thus preventing non-unilorm removal
of the metal - phosphates and non-uniform
hydrolysis of.the silicyl phosphates In some
cases, especially where the pH of the leach
solution approaches.0.7, agitation of the
carrier material during leaching-is necessary
to prevent formation of crusts of metaI
hydroxides or hydrated oxides formed by
hydrolysis of the metal phosphates.
This digestion procedure should be carried
out until the carrier. material is substantially
free of metallic phosphates. Normally, sub
stantially all of the soluble.materials will be
leached from the carrier material and the
silicyl-phosphate will be completely hydro
4sized in approximately one hour of digestion
time, and in many cases substantially com
plete solution and hydrolysis 'will be effected
in about 30 minutes. It is desirable that the
minimum digestion time be employed.
Following this first digestion stage, the
carrier material is- drained and washed
thoroughly in the manner described above
for the first digestion stage, with the sole
exception that the wash liquid consists of
non-acidified hot water. The washing is

preferably accomplished in several stages,
each stage employing a fresh portion-of hot
water. The washing should be continued
until the carrier material is substantially free
of acid. During this treatment any residual
metallic phosphates will be removed and any remaining silicyl
phosphate will be hydro
lyzed.
Following the washing stage, the carrier
material is dried. For this purpose, any
means common to the artHven drying, for
example-may 'be' employed. The dried
material is then impregnated with an aqueous
solution of phosphoric acid in accordance
with known procedures to form the superior
composite catalyst of the present invention.
The impregnation is carried out in the same
manner as heretofore described iri preparing
the carrier material for the heat treatment
i.e. the dried carrier material is soaked in the
aqueous phosphoric acid for 'a sufficient
period of time to allow the carrier material
to become saturated with the acid, the
excess- acid is removed and the impreg
nated carrier material is allowed to drain
thoroughly. In generaI, a soaking period of
from about to 1 hour will be found suffi
cient, and an equal length of time for drain
age normally prepares the catalyst' for - use.
In use the - concentration of H3PO4 in the
solution with which the carrier is impreg
nated is generally at least 70% by weight and preferably is from about
75 to about 95 D/Q by weight. The concentration of HYPO4 in the
aqueous acid solution supported on the carrier material during the
olefin. hydration process is preferably maintained in the same
concentration- range. Further, the can rier pore loading is preferably
below about 90% and more preferably -is between about 70--80 /o . The
term " pore loading "'indicates the relationship between the actual
amount of acid present on the carrier material and the maximum amount
of acid with which it can become impregnated, it being understood that
the carrier material and- the acid are in such case in the same
physical states as under actual operating conditions. The maximum pore
loading may.be determined experimentally, but for many purposes, it is
more convenient and sufficiently accurate to calculate the maximum
pore loading from the total porosity of the carrier and the specific
gravity of the acid solution. For these calculations, the porosity af
the carrier and the concentration of H,PO, in the acid solution have
the same values that they have under actual operating conditions. At
these desired pore loadings mentioned above catalyst activity is at
its maximum and seepage is kept to a minimum. These conditions are
most conveniently attained by an alternative treatment consisting of-
saturating the treated carrier material-- (pore loading=100%} with a
more dilute solution of' - phosphoric acid and operating under such
conditions that part of the water content of the phosphoric acid
solution is removed, bringing the -concentration of H3PO4- and the
pore loading to the desired levels simultaneously. For this purpose,
the dilute phosphoric acid used to impregnate the treated carrier
material initially contains. somewhat less than 70% H3PO by weight.
The acid concentration should not be below about 50% by weight, for
otherwise the. final composite catalyst will be incompletely saturated
with the acid.
In general, an acid strength of about 55 to 65 % by weight has been
found most suitable.
The catalysts prepared in accordance with this process have been found

to be relatively insensitive to changes in the water content of the
reaction zone, and,therefore, may be used directly in the process for
hydrating the olefin without any preliminary treatment.
When employed in the process for effecting hydration of the olefin
hereinafter described, the catalyst loses water until the strength of
the phosphoric acid on the carrier rises until the solution of the
acid contains at least about 70% by weight of phosphoric acid, which
level is maintained - throughout the duration of the reaction.
According to a further feature of the present invention a process for
the preparation of an alcohol by direct hydration of an olefin,
comprises contacting a gaseous mixture of an olefin and water at
elevated temperature and pressure with a composite catalyst prepared
as defined above, the temperature, pressure and molecular ratio of the
reactants being controlled so that the aqueous solution of phosphoric
acid supported on the carrier has a concentration of at least 705: by
weight.
By the use of a catalyst prepared in accordance with the present
invention, the olefin conversion level is much higher than that
previously obtainable, and while the conversion level may decline with
time, the rate of decline is much lower than with the olefin hydration
catalysts known in the art.
In effecting the hydration of an olefin, the various process
conditions, i.e. temperature, pressure and molar ratio of water vapour
to olefin vapour in the feed, are adjusted so as to bring the
concentration of H3POr in the aqueous solution of phosphoric acid on
the carrier to at least 70 O by weight as soon as possible after the
process has gone on stream, and also whenever fresh acid is added as
make-up during the hydration process.
The hydration process is brought on stream by passing a heated gas
through the catalyst bed until the reaction temperature is approached,
whereupon the feed mixture of
Normally, mixtures of the olefins with other hydrocarbon gases - may
be - emplbyed. It is preferred that the other components of such
mixtures be compounds which are substantially inert to the action of
water vapour in the presence of the catalyst.
The alcohol produced by the hydration of the olefin is condensed out
of the gaseous effluent emerging from the catalyst bed, and by
suitable choice of condenser and condensing temperature. The product
alcohol and water vapour can be condensed with the
condensation of but a minor amount, for example about 5 or 10%. of
-by-product ether which is thereafter removed from the alcohol
in known manner as by distillation. The
remaining gaseous ether, together with unreacted gaseous olefin, is
recycled through the system in admixture with additional
quantities of olefin and water vapour, the process thereby being
continuous.
In the following Examples, Example I illustrates the preparation of a
composite catalyst according to the process of the present invention
and Examples II to VI, the use of such a catalyst in the hydration of
olefines.
EXAMPLE I
A composite catalyst comprising phosphoric acid impregnated upon a
siliceous carrier was prepared by the following procedure:
100 parts of a diatomaceous earth material designated by the
manufacturer (Johns
Mansville Corporation) as "Celite VIII," in the form of pellets of
generally cylindrical shape measuring approximately 5/32 by 3/16 inch,
were soaked for approximately one hour at room temperature in excess
aqueous phosphoric acid containing 85% by weight H3PO4. The excess
acid was then removed by allowing. the carrier material to drain for 1
hour. The impregnated carrier material was then heated in an oven at
300"C for 3 hours, the pressure being atmospheric and the atmosphere
surrounding the carrier material containing a partial pressure of
water equal to approximately 200 millimetres of mercury. The material

was then cooled and leached by digesting the material for 1 hour with
acidified water maintained at
100"C. The water had an initial pH of 0.35, the acidity being
furnished by the addition of sulphuric acid. The volume ratio of water
to carrier material was approximately 1.5.
The carrier material was then drained and the leaching repeated using
fresh acidified water.
The acidified water was then drained from the material and the
leaching repeated twice more following the same procedure but
substituting pure water for the acidified water.
The carrier material was then drained and dried in an oven at about
125"C. It was then soaked in an excess of an aqueous solution of
phosphoric acid containing 55 % by weight of HaPO4 for approximately
one hour, after which itqwas drained for about 2 hours.
EXAMPLE II
200 Parts of the catalyst prepared in
Example I were charged to a reactor, and a gasedus mixture comprising
water vapour and ethylene vapour in a molar ratio of 0.5:1.0 was
passed through the catalyst bedat a VSVM of 27. The temperature of the
catalyst bed was maintained between 275 C and 285"C. The total
pressure. was 1000 pounds per square inch. No phosphoric acid was
added during the run. The initial conversion level of ethylene to
ethyl alcohol was 5.3 %. At the end qf 400 hours of operation the
conversion level was 4.8%. Inspection of the catalyst during and at
the end of the run showed that no carbon deposit or fines had
resulted. Comparison of the catalyst's physical strength befbre and
after the run showed a negligible physical strength loss.
A duplicate run was conducted substituting for the catalyst specified
above a catalyst comprising " Celite Vm" as received from the
manufacturer impregnated with an aqueous solution of phosphoric acid
of the same concentration as was employed with the treated carrier in
preparing the catalyst in accordance with the invention. The initial
conversion level in thins run was 4.2%, and the final conversion level
was about 3.6%.
EXAMPLE 111
The modified "Celite VIII"-phosphoric acid catalyst employed in
Example II was re-impregnated with an aqueous solution of phosphoric
acid containing 55% by weight
H3PO4, and was employed in the hydration of ethylene under
substantially the same conditions as indicated in Example II. The
conversion level remained at 5.5% through out the duration of a 30
hour run. This value may be compared to the value 5.3 % obtained at,
the end of the first- 30- hours of the run reported in Example It.
during the 30 hour period of the second continuous operation, there
was no observed decline in the activity of the re-impregnated
catalyst.
EXAMPLE IV
200 parts of the catalyst prepared in
Example I were charged to a reactor and heated in a stream of nitrogen
for one hour, the catalyst bed temperature being approximately 275"C,
and the total pressure being 1000 pounds per square inch gauge. A
water vapour-ethylene vapour feed mixture in a molar ratio of 0.5:1
was then fed into the reactor. The activity of the catalyst after this
treatment was 4.8, the catalyst bed temperature being approximately
275"C, and the feed rate being 47 VSVM. The run was repeated with 200
parts of fresh catalyst which was not subjected to the above
pretreatment. The activity level of this catalyst was substantially
the -same as that of the pretreated catalyst, i.e. approximately 4.6
,' total conversion, illustrating the indifference of the catalyst of
the present invention to start up procedures in which no water is
present.
EXAMPLE V
The optimum operating temperature for the catalyst prepared by the-
procedure of

Example I - was determined by three runs each at a different catalyst
bed temperature.
The conditions, other than the temperature, were identical to those
indicated in Example
II. The following results were obtained ,EtAlvlene
Run Teinperatie Conversion Level ('C) ( O)
1 250 4.7
2 275 5.4
3 300 4.5
EXAMPLE VI
A run of extended duration was made in which the process was
on-stream- for 100 days, under conditions which were substantially the
same as indicated in Example II.
The following data were obtained:
<img class="EMIRef" id="026598819-00080001" />
- Initial (Start of run) - ,-. -- Final
(End of run)
Parts product Conversion Parts product Conversion
per day level ( /O) - per day level ( O)
Treated carrier 14.5-15.5 4.24.6 ' ' - io -
3.2
Treated carrier -- . 16.5 5.3 15.5 - 4.6
What we claim is : - -
1. A process for- the production. of a composite catalyst comprising
saturating a porous. inert diatomaceous carrier material with a strong
aqueous solution of phosphoric acid, heating the resulting impregnated
carrier material in can atmosphere containing water vapour having a
partial pressure which is less than the partial -pressure of water
vapour in equilibrium with an aqueous solution of phosphoric acid at
the temperature at which the heating is effected, digesting the heated
carrier material with acidified - hot water having a pH less than
about 1, washing the digested carrier material with hot water, drying
the washed -carrier material and impregnating the dried carrier
material with an aqueous solution of phosphoric acid.
2. A process as claimed in claim 1, wherein said carrier- material is
saturated in said first impregnation stage with an aqueous solution of
phosphoric acid having a concentration of at least 70% by weight.
3. A process as claimed in claim 1 or claim 2, wherein said -
impregnated carrier material obtained in said - first impregnation
stage is heated in the water vapour-containing atmosphere at a
temperature - between about 225 C and about 325 C.
4. A process as claimed in any one of the preceding daims, wherein
said impregnated carrier material obtained in said first impregnation
stage is heated in an atmosphere containing- water vapour at a partial
pressure between about 150 and 300 millimetres of mercury.
5. A process as claimed in any one of the preceding claims. wherein
the aqueous phosphoric acid with which said washed and dried carrier
is impregnated has a concentration of between 55 and 65''o by weight
of H3POo, and said acid is thereafter concentrated iZ2 sit on said
carrier to a concentration above 70% by weight of H3PO.
6. A process for the production of a composite catalyst substantially
as described hereinbefore with reference to Example I.
7. A composite catalyst when prepared by a process as claimed in any
of the preceding claims wherein the carrier material has an average
pore radius of between about 3500
A and about 6500 , at least 5% of the pores having a radius of less
than about 5QO A
8. A catalyst as claimed in claim 7, comprising a granular carrier
material impregnated with an aqueous solution of phosphoric acid
containing between- 75,u and 95''u bp weight of H3 P.O4.
9. A composite catalyst when prepared by the process claimed in any
one of claims 1-6.
40, A process for the preparation of an alcohol by direct hydration of

an olefin, which comprises contacting a gaseous mixture of an olefin
and water at elevated temperature and pressure with a composite
catalyst as claimed in any one of claims 7 to 9, the temperature,
pressure and molecular ratio; of the reactants being controlled so
that the aqueous solution of phosphoric acid supported on the carrier
has a concentration of at least 70% by weight.
11. A process as claimed in claim 10, wherein. the catalyst is
maintained at a temperature between 265 and 300 C.
12. A process as claimed in claim 10 or claim 11, wherein small
amounts of phosphoric acid are added to the support during the process
to maintain the catalyst activity level.
13. A process as claimed in any one of claims 10-12, wherein the
olefin is ethylene.
14. A process for the preparation of an alcohol by direct hydration of
an olefin as claimed in any one of claims 10-13 substantially as
described hereinbefore with refer
* GB786239 (A)
Description: GB786239 (A) ? 1957-11-13
Improvements in thermostatic control devices
BE547217 (A) CH345700 (A) DE1125094 (B) FR1151543 (A)
NL92738 (C) US2786990 (A)
BE547217 (A) CH345700 (A) DE1125094 (B) FR1151543 (A)
NL92738 (C) US2786990 (A) less
PATENT SPECIFCATION
-786,239
Date of Application and filing, Complete Specification: Dec 15, 1955.
No 36023155.
Application mode in United States of America on April 28, 1955.
Index at Acceptance:-C Gass 38 ( 5),' Bl S( 2 C 2: 12), B 2 (A 5 A 2:
E).
International Classification:-H 02 e.
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 Russell Frederick Garner of Robertshaw Thermostat Divisions
Robertshaw Fulton Controls Company, Youngwood, Pennsylvania, United
States of America, a citizen of the United States of America.
COMPLETE SPECIFICATION-
Improvements in Thermostatic Control Devices.
We, ROBERTSHAW FULTON CONTROLS COMPANY, a Corporation organized under

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