Literature review for production of Diethyl ether. Literature Review includes History, Market Worldwide, Production capacity, properties, Selection of process.

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CHAPTER 2
LITERATURE REVIEW
This Chapter gives information about the component diethyl ether (DEE). The Chapter is
starting with history of diethyl ether (DEE). The physical properties like melting point,
density, heat of vaporization etc. and chemical properties are included. Then various
applications are written. The various processes for production of diethyl ether (DEE) are
described and selection of process with justification is written.
2.1 History
Ether (from the Latin "aether" and the Greek "eithr," or "the upper and purer air") is
believed to have been first synthesized about 1540 by German botanist and chemist
Valerius Cordus, who called his discovery "sweet oil of vitriol" and praised its medicinal
properties. Paracelsus, a contemporary of Valerius, noted that the "oil" induced sleep in
chickens when added to their feed. Frobenius (Froben) named the liquid "ethereal spirits"
or "ether" in 1730. [16]
In Georgia Dr. Crawford W. Long may have been the first person to apply his social
experiences with ether to surgery. A graduate of the University of Pennsylvania, Crawford
is said to have observed a participant at a frolic take a heavy fall but show no indication of
pain. In 1842 Long performed three minor surgeries using sulfuric ether, a form of ether
with chemical properties similar to those of diethyl ether. Long apparently did not realize
the medical significance of what he had done and failed to publicize his discovery. He
published his results only after anesthesia had been hailed as a major breakthrough.
The knowledge of ether as an anesthetic spread rapidly. The medical establishment and
the public quickly and gratefully accepted the use of ether inhalation for painless surgery.
Within months, surgery using ether anesthesia was being performed in England. In
Germany Johann Friedrich Dieffenbach, a pioneer in plastic surgery, wrote: "The
wonderful dream that pain has been taken away from us has become reality. Pain, the
highest consciousness of our earthly existence, the most distinct sensation of the
imperfection of our body, must now bow before the power of the human mind, before the
power of ether vapor." [17]

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2.2 Physical Properties of diethyl ether (DEE)
Here the Physical properties of diethyl ether is given in the table 2.1
Table 2.1 : Physical properties of diethyl ether[5]
Property Value
CAS number 60-29-7
Molecular weight 74.14 gm/mol
Freezing point -116 ºC
Boiling point 35 ºC
Density at 20°C, g/mL 0.71
Heat of formation (-65.2) kcal/mole
Viscosity at 20°C, mPas 0.23 cp
Color Colorless
Solubility Moderately soluble in water
(6.9ml/100ml) and soluble in
alcohol.
Auto ignition temperature 180 º C
Flash point -45 ºC (closed cup)
Surface tension at 20°C, dyne/cm 17.3 dyne/cm
Heat of vaporization, kJ/mol 6.215 kcal/mole
2.3 Chemical Properties of diethyl ether (DEE)
Reactions of diethyl ether [1]
1. HALOGENATION: - When diethyl ether treated with Cl2 or Br2 in the dark,
substitution product are obtained. The extent of substitution depends upon the
reaction condition. Halogenations preferentially take place at ά- carbon atoms.

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CH3CH2-O-CH2CH3 + Cl2 → CH3CH(Cl) -O-CH2CH3 (2.1)
Diethyl ether ά- chloro diethyl ether
CH3CH(Cl) -O-CH2CH3 + Cl2 → CH2(Cl)CH(Cl) -O-CH2CH3 (2.2)
ά- chloro diethyl ether ά,ά- dichloro diethyl ether
2. FORMATION OF PEROXIDE:- Ether combine with atmospheric oxygen to form
peroxide.
CH3CH2-O-CH2CH3 + O2→ CH3C(OOH)H-O-CH2CH3 (2.3)
Diethyl ether peroxide of diethyl ether
CH3CH2-O-CH2CH3 + PCl5 → 2 CH3CH2Cl + POCl3 (2.4)
Diethyl ether ethyl chloride
3. Combustion:
CH3CH2-O-CH2CH3 + O2 → CO2 + H2O (2.5)
Diethyl ether
4. Dehydration Al2O3
CH3CH2-O-CH2CH3 → CH2 = CH2 + 2 H2O (2.6)
Diethyl ether 360ºC ethylene
5. P + HI
CH3CH2-O-CH2CH3 → C2H6 (2.7)
Diethyl ether ethane
6. Oxidation K2Cr2O7 + H2SO4
CH3CH2-O-CH2CH3 → CH3CHO → CH3COOH (2.8)
Diethyl ether acetaldehyde acetic acid

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2.4 Use of diethyl ether (DEE)
Now a day’s diethyl ether has a wide application in the medical and in the industries. The
diethyl ether mainly uses for following purpose.[12]
1. Good solvent or extractant for fats, waxes, oils, perfumes, resin, dyes, gums &
alkaloids.
2. When mixed with ethyl alcohol, diethyl ether becomes an excellent solvent for
cellulose nitrate in manufacturing of guncotton, collision solution & pyroxylin
plastic.
3. As an extractant for acetic acid as well as other organic acids.
4. As a denatured in several denatured alcohol formulas.
5. As a starting fuel for diesel engines & as an entrained for dehydration of ethyl &
isopropyl alcohol.
6. As an anhydrous inert reaction medium for the grignard & wurtz-fitting reaction.
7. As a general anesthetic in surgery. Most commonly either inhaled or ingested.
Inhalation seems to be the more popular route, due to quicker onset of effects and
less side effects.
8. A tincture of diethyl ether with alcohol called Hoffman's Drops was popular in
the 1800s mostly for women.
9. It is useful as a commercial source of ethylene in plant that does not have access
to petroleum refinery gases.
2.5 Production Techniques
2.5.1 Ethanol Selective Dehydration Reactions
Ethanol Selective Oxidation and Dehydration Reactions Catalytic transformation of
ethanol over vanadium/silicate molecular sieves indicated the formation of acetaldehyde,
ethylene and DEE.
Formation of acetaldehyde was mainly due to the involvement of vanadyl species (V=O),
while DEE formation was due to the simultaneous involvement of vanadyl and V-O-Si
species on the surface.

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Ethanol dehydration reaction was worked and the main products obtained by this reaction
are Diethyl ether and ethylene.
Conventionally, alcohol dehydration reactions can be achieved, by heating the alcohol
with strongly acidic compound like H2SO4 or H3PO4. Researchers are interested in
replacing these hazard liquid acids by environmentally friendly solid acids.
Different transition metal catalysts such as titanium oxides, magnesium oxides,
Fe2O3/Al2O3, cobalt oxides, silver salts of tungstophosphoric acid, Fe2O3,Mn2O3 and
calcined physical mixture of both ferric and manganese oxides with alumina and /or silica
gel were used for catalytic dehydration reaction of ethanol.
Different heteropoly acid catalysts and their salts such as barium salt of 12-
tungstophosphoric acid, potassium and silver salts of tungstophosphoric acid and their
supported form which were prepared by incipient wetness method using silica as a support,
different types of zeolites such as H-Mordenites, H-ZSM5 zeolites, H-beta zeolite, H-Y
zeolite and silica-alumina, as well as gamma-alumina, silica-alumina, aluminophosphate–
alumina, phosphoric acid on γ-alumina and on silica were used in ethanol dehydration
reaction.
Different reaction models were proposed for ethanol dehydration reaction. Saito and
Niiyama, 1987, suggested two kinds of adsorbed ethanol molecules, namely physisorbed
and chemisorbed. In their model, physisorbed ethanol behaves like a reservoir of
chemisorbed ethanol which was later converted to products. They suggested that ethylene
was formed by the decomposition of ethanol while ether was formed with both chemically
activated ethanol and the physically sorbed one.[13]
2.5.2 Barbet Process
The continuous dehydration of ethyl alcohol by H2SO4 was first described by P.Boullay in
1809, which called BARBET PROCESS. [12]
In this process concentration H2SO4 and 95% Ethyl alcohol are charged into a lead lined
steel kettle in the ratio of 3 parts acid to 1 parts alcohol. The reaction is started by heating
the mixture to 125-140 º C with a steam jacket or internal steam coil.
A supply of alcohol vapor is continuously fed into the acid alcohol mixture at a rate to
maintain the temperature at 127 º C. The vapor from still consisting ether, alcohol and

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water passes through caustic scrubber to remove traces of SO2 and entrained H2SO4. The
alkaline solution formed, containing small amount of ether and alcohol, passes from the
bottom of the scrubber to the lower level of the fractionating column. At this point the
ether and alcohol are removing as the aqueous solution is discharged as waste.
The vapor from the top of the scrubber, consisting of ether, alcohol and water, separated
in continuous fractionation water passes from the column as waste, while ethyl alcohol
(95%) is withdrawn from the Centre of column and return to vaporizer for recycling. Ether
vapour from top of column through reflux condenser maintained at 34 º C.
Fraction boiling above this temperature are condensed and returned to the column, ether
vapor are condensed and run into the storage tank. This technical or conc. Ether contain
very small amount of alcohol, water, aldehyde, peroxide and other impurities. The more
refined grades, such as anesthetic ether, are obtained from technical ether by re-distillation
and dehydration followed by alkali or charcoal treatment.
This is a continuous process and may run for months before recharging with H2SO4.
C2H5OH + H2SO4→ C2H5HSO4 + H2O (2.9)
C2H5OH + C2H5HSO4 → C2H5OC2H5 + H2O (2.10)
Side reaction formed tarry product and SO2 make periodic recharging necessary. The yield
of technical ether is 94-95% based upon the ethyl alcohol processed. Benzene sulfonic
acid can be used instead of sulfuric acid at some lower temperature. The second process is
used to produce industrial diethyl ether. It is large scale process and is purity is lower than
that produce by barbet process.
2.5.3 Industrial Process
Most commercial diethyl ether used is obtained as a byproduct in the synthetic
manufacturing of ethyl alcohol from ethylene by sulfuric acid process. This method may
be modified to produce only diethyl ether. [2]
The reactions are,
C2H4 + H2SO4→ C2H5HSO4 (2.11)
C2H5HSO4 + H2O → C2H5OH + H2SO4 (2.12)

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C2H5OH + C2H5HSO4 → C2H5OC2H5 + H2SO4 (2.13)
Ethylene, produce by cracking hydrocarbon, is absorbed by conc. H2SO4 at fairly high
pressure under controlled temp. Conditions to yield mixed ethyl hydrogen sulfate and
diethyl sulphate. This mixture would contain 1-1.5 moles of ethylene per mole of H2SO4
and would be hydrolyzed with water to produce ethyl alcohol, with diethyl ether as a
byproduct.
As shown in flow chart, the mixed sulphates are pumped into reactor under pressure with
sufficient water to obtain a H2SO4 strength of about 60% on a hydrocarbon free basis. A
temperature of about 125 º C is maintained in reactor, which should be of sufficient size
to permit about 3 hr contact time. If a higher temperature is maintained the contact time
can be reduce, but this result in higher pressure. The proper balance between temperature
and pressure is determined by an economic balance between the expense of equipment and
cost of operation. The objective of to approach within reasonable limits, the equilibrium
in the ether- alcohol- water- H2SO4- ethyl sulphate system, which determined the
maximum conversion to be expected.
Ethyl alcohol recorded from alcohol tower is recycled to the reactor. This increase the
mole ratio of equivalent ethylene to H2SO4 that is favorable to high ether conversion.
When the process is put into operation, the amount of recycle alcohol increase until system
is in balance. This is usually about 3 mole ethylene per mole H2SO4, depending upon the
ethylene present in the mixed sulfates, resulting in an ether conversion of about 40%.
The reactor mixture is fed at a uniform rate to a stripping still with sufficient water to
reduce the acid strength to about 50% on hydrocarbon free basis. Ether, alcohol and water
are removed from H2SO4 by stripping with live steam at pressure slightly above
atmospheric. The vapor are passed through a vapor scrubber counter current to dilute
(10%) caustic soda solution to remove sulfur dioxide and traces of entrained H2SO4. the
vapor from scrubber are condense, passed through separator, and run into storage tank
before rectification. The ethylene recovered from separator is sent to a compressor and
returned to the ethylene- absorption of ethylene. If alcohol is raw material, the 65% acid
is returned to reactor.
The ether- alcohol- water mixture is sent to finishing system consisting essentially of
fractionation tower and washer. The ether is separated from alcohol and water in ether
tower and is run through water washer to remove alcohol present. Then it is run through a

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second wash column where it is treated with an alkaline permanganate solution. The
treated ether flows to an accumulator tank. The ethyl alcohol- water mixture from the ether
tower is sent to alcohol tower, where constant boiling mixture at alcohol and water (95%
by vol.) distills over. Both ether and alcohol towers operate as substantially atmospheric
pressure.
The treated ether, contain small amount of water is fed to dehydrating tower that operates
at about 100 psig. The distillate from this tower separates into two layers; the lower
aqueous layer is withdrawn. The dry ether passes from base of dehydrating tower to
finishing tower, which operates at about 50 psig and give highly refined ether as an
overhead product, while very small stream to higher boiling material is removed from
base. It is desirable to handle diethyl ether product in closed system and store it in pressure
drums or sphere. An inhibitor such as 1-napthol is added to prevent peroxide formation.
2.6 Selection of Process and Process Details with Justification
· In barbet process side reaction formed products which lower the conversion of
diethyl ether, but no side reaction taken place in the selective dehydration of
ethanol using solid catalyst.
· Use of solid catalyst reduce the contamination of H2SO4 in product.
· Solid catalyst gives higher conversion of ethanol and selectivity of diethyl ether.
· In this process the hazard liquid acid (H2SO4) by environmentally friendly solid
acid catalyst.
2.7 Process for Manufacturing of Diethyl Ether
The process begins with a 1MM gallon feed storage tank. A tank of this size can hold a
one month supply of ethanol. The feed is then pumped to a high pressure, vaporized, and
passed through a packed bed isothermal reactor. The reaction products are sent through a
separation train designed to purify the Diethyl Ether. The product is 99.5%+ pure. The
Diethyl Ether product stream is sent directly into storage tanks available. The separation
train also produces a waste stream of mostly water, which is sent directly to an off-site
waste treatment facility. [2]

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2.7.1 Feed Storage
A 95% solution of ethanol (5% water) feed is stored at atmospheric pressure and
temperature in a 1MM gallon, floating-roof storage tank. This volume is large enough to
hold a one month supply of ethanol and will be replenished by the ethanol plants located
conveniently in the area. The large volume of storage allows the plant to continue
operation
Fig.2.1: flow sheet of Diethyl ether (DEE)

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Table 2.1: name and number of equipment in the flowsheet
Number 1 2 3 4 5
Name Reactor Heat
exchanger
Distillation
column
Distillation
column
Flash
vessel
6 7 9 10 11 12
Heat
exchanger
Flash
vessel
Heat
exchanger
Heat
exchanger
Pump Heat
exchanger
for one month when ethanol is not available. In addition, it provides flexibility in
scheduling feed replenishment and helps ensure consistent production.
2.7.2 Reactor Section
It is packed bed reactor. The reactor contains packed bed of alumina catalyst. The main
reaction is,
2C2H5OH (C2H5)2O H2O (2.14)
Ethanol DEE
Reaction is exothermic, reversible, and limited by equilibrium. The reaction occurs at
medium temperatures (400-600 K) and high pressures (1000-1500 kPa). The alumina
catalyst minimizes (but does not eliminate) side reactions at higher temperature. For
simplicity, assume that the only side reaction that occurs in Reactor is the dehydration
of DEE to form ethylene:
(C2H5)2O → H2O + 2C2H4 (2.15)
DEE Ethylene
The primary reaction is limited by equilibrium. The selectivity of the ethylene side
reaction is a function of reactor temperature and pressure.
In this process isothermal reactor is used. Inlet temperature is 200o
C and pressure is
1500KPa. It is gas phase reaction. The conversion of ethanol is 52.5% and selectivity
of diethyl ether (DEE) is 93%. [7]
The reactors is filled to capacity with γ-alumina catalyst in the form of 1cm diameter
spherical pellets. After regular time interval catalyst is necessary to discard and replace all

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of the catalyst. Regeneration is not feasible because the loss of catalytic activity is due
directly to irreversible damage caused by constant exposure to the high temperature and
pressure conditions in the reactor.
Before reactant enter in the reactor from feed storage tank it is mixed with recycle stream
and after that it is heated up to 250o
C.
Upon leaving the reactor, the products enter HX-6 which lowers their temperature to
166o
C. After product stream enters heat exchanger reduce the temperature up to 37o
C. It
is desirable to remove as much heat as possible from this stream since the separation train
requires low temperatures.
2.7.3 Separation Train
After the reactor effluent stream passes through heat exchanger, it enters the separation
phase of the process. The separations section is designed to bring the Diethyl ether(DEE)
product to a 99.5% purity using as little equipment and as few utilities as possible. Effluent
stream enters in flash vessel (5), at 37o
C high pressure knock out drum. The overhead
stream from flash vessel, contains most of the ethylene that is formed in an undesirable
side reaction along with small amounts of DEE and ethanol. This stream is sent to another
process as fuel gas.
Bottom of the flash vessel is heated to 80°C in HX-12 using low-pressure steam. The exit
stream from HX-6, enters the DEE purification column (3) where the DEE is separated
from the water and ethanol. It should be noted that since the feed to column contains small
amounts of ethylene a partial condenser is used. The overhead product from this column
is then cooled in HX-9 and is then fed to the low pressure flash vessel (7). The overhead
stream from flash vessel is vented to flare and the liquid product is the DEE 99.5+%
product stream that is sent to storage where a peroxide inhibitor is added.
The bottom product from column (3) is sent to a second column (4), where the ethanol is
purified as the top product to a 85 mol% pure aqueous mixture. This mixture is pumped
back to the feed pressure using Pump (11) and returned to the front end of the process. The
bottom product stream, Stream 12, is water with trace amounts of organic material that
is cooled to 37°C in HX and then sent to wastewater treatment prior to discharge to the
environment.