SYNTHESIS OF ETHYL ETHER
By Zaphraud
Courtesy of the Fine Cafe BBS
------------------------

This is extremely dangerous!

ETHYL ETHER, or CH3CH2-O-CH2CH3, is a great solvent for many things, but
its extremely flammable. More flammable than anyone should be comfortable
with. The vapors 'hug' the ground, and in dry air explosive peroxides can
form - in other words, even in a spark/flame free environment you can still
explode... for this reason its probably a good idea to have some way of
venting any vapors FAR FAR AWAY and not use ether on dry days...

ETHER is prepared from ETHYL ALCOHOL by heating it with SULFURIC ACID... the
reaction proceeds thru an intermediary, "Ethyl sulfuric acid", as do most
reactions of this type.

The reaction is conducted as follows:

Dry (anhydrous) or nearly dry ethyl alcohol is allowed to flow into a mixture
of alcohol and sulphuric acid heated to 130c-140c. The vapors are collected,
and ether and some alcohol and water condense out. The sulphuric acid is a
catalyst, but since it becomes more and more dillute with water produced by
the reaction, the process becomes inefficient (which is why anhydrous ethanol
is the best!)

The temperature of the reaction should be controlled carefully. At
temperatures below 130c, the reaction is too slow and mostly ethanol will
distill. Over 150c, the ethyl sulphuric acid decomposes, forming ETHYLENE
instead of combining with ethanol to form ether!
                             ______________________
  ___________    COLD WATER  ______________________  WATER OUTLET (cools
 |           |                    |__ __ \/  \                     ether)
 |  ETHANOL  |       (fractioning | __| \__/\ |
 |  FEED     |        column)_____|__ |_     ||
 |  TANK     |              / __________(out)||
 |_______  __|   ______    _||______         ||
         ||     / ____ \  |________ |       /  \  (ether
         ||     ||    ||  | ________|      /    \  reciever)
         ||     ||    ||  |________ |     (______)
         ||  ___||_   ||__| ________| (caustic scrubber to remove
         || |      |  \____         |  water and H2SO4)
         || |      |       \________/
         || |******| (reaction chamber heated
         || |_  ___|  with steam coils)
         ||___||
         \_____/

95% ethanol may be recovered from water + CH3CH2OH pulled from the bottom of
the fractioning column (marked 'out')... by connecting it to another column
and distilling it...

This may be converted to 100% ethanol by mixing the 95% with calcium oxide
and distilling - the water is used up to make Calcium hydroxide! This in
turn can be re-fed to the "FEED TANK" after cooling...

=============================ANOTHER APPROACH===============================
From: eleusis@netcom.com (Eleusis)

Though this is not the most pleasant process, Diethyl Ether may be
produced by the condensation of ethanol. To do this, assemble a typical
fractional distillation setup with a vigreux column and a three neck
flask. Don't forget to drop a stirrer magnet into the flask before
clamping everthing up, and you will be heating this on an oil bath (no
flames allowed when Ether is around, you know). The vigreux column goes 
in the central neck, an addition funnel in one side beck, and a 
thermometer goes in the other side neck. Add 2x moles (where the x is
a multiplier, 1 = 2 moles, 1.5 = 3 moles, etc...) of the azeotrope of
Ethanol (ie - Everclear) to the flask. Add 2x moles of concentrated 
Sulfuric Acid (ie - Instant Power Drain Opener) to the Ethanol slowly 
(it will heat because of the water). Turn on the stirrer, turn on the 
heat, and bring the flask up to 130C. Make sure your condenser is well 
supplied with cold water, and continue heating to 135C or so. Once 
distillation commences, slowly add up to another 2x moles of Ethanol 
through the addition funnel at a rate equal to the drops coming from 
the condenser. 2 moles of alcohol should take 1 hour with a decent
vigreux column. A shorter column (or, gasp, no column at all) will
require slower distillation (and if you don't use a column, you will
have to do some extensive washing of the product with saltwater).
Dump the receiver flask contents into a large beaker or bowl and swirl
with 10% Sodium Hydroxide solution until the pH is neutral. Pour this
mixture into a separatory funnel to separate the Ether from the aqueous
hydroxide and wash twice more with equal volumes of half-saturated
Sodium Chloride solution (~18g/100mL of water @ room temp). Let the last
wash solution + Ether rest in the flask until everything has settled,
then carefully drain off the wash, and pour the Ether out of the top
into a round bottom flask. Add 15g of Calcium Chloride (Damp-Rid) for
every mole of Ether, drop in stirrer magnet and stir for 2 hours.
Distill the Ether from the Calcium Chloride by heating on a bath (oil
or water) at no higher than 45C! Collect distillate that comes over in
the range of 31 to 36C.

=============================ANOTHER APPROACH===============================

Diethyl Ether. This is also called ethyl ether or ether and must not be
confused with petroleum ether. If, for example, you see a formula calling
for ether, then it refers to diethyl ether, if it does not specify
petroleum ether, then do not use petroleum ether. 100 g of ethanol (dry
ethanol is best) is placed in a 1/2 liter distilling flask, and with good
cooling, 180 g of concd sulfuric acid is added slowly. This flask needs a
thermometer fitted, so that the bulb dips down below the liquid, and extend
the addition funnel, so that the ethanol can be added below the surface of
the acid. Heat and maintain the mixture's temp at 140-145ø by heating on a
sand bath. Ethanol is run in from the addition funnel at the same rate as
the liquid distills over (about 2 drops per second). Mark the flask before
distilling, so that you can be sure of the addition rate. After about 150 g
of alcohol (ethanol) has been added, stop heating. The distillate will
require the following purification steps: Shake twice with 50 cc of 10%
caustic soda solution, to free from sulfuric acid. Shake twice with 50 cc
of saturated sodium chloride solution, to free from ethanol. The ether is
then dried over anhydrous calcium chloride for 24 hours and distilled on a
water bath, collecting the fraction boiling at 35ø. Yield: 100 g.
    
    Anhydrous Ethyl Ether. This is for those formulas calling for dry,
pure, or anhydrous ether. The ether product from above is dried over thin
slices of metallic sodium (metallic sodium wire works well also) for 24
hours. Then the ether is distilled on a water bath, over fresh (fresh means
a different batch than what you used to dry with) metallic sodium. Note:
Ether develops explosive peroxides upon sitting for any length of time,
even if just purchased from a supply house. Therefore, before handling
ether, which has been stored, shake with ferrous sulphate or with lead
peroxide. To keep peroxides from forming in fresh ether; add several
sections of copper or iron wire to the dark container and store in a cool
place.
