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Ethyl Acetate Synthesis

This document provides instructions for preparing absolute ethanol from grain alcohol and then using the ethanol to synthesize ethyl acetate. It involves dehydrating calcium oxide to remove water from the grain alcohol through refluxing. The ethanol is then combined with acetic acid and sulfuric acid and refluxed to produce crude ethyl acetate, which is purified through fractional distillation and washing. The overall process yields over 70g of pure dry ethyl acetate.

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Ji Chem
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212 views1 page

Ethyl Acetate Synthesis

This document provides instructions for preparing absolute ethanol from grain alcohol and then using the ethanol to synthesize ethyl acetate. It involves dehydrating calcium oxide to remove water from the grain alcohol through refluxing. The ethanol is then combined with acetic acid and sulfuric acid and refluxed to produce crude ethyl acetate, which is purified through fractional distillation and washing. The overall process yields over 70g of pure dry ethyl acetate.

Uploaded by

Ji Chem
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
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Ethyl acetate synthesis

10) Preparation of Absolute Ethanol from Grain Alcohol

Absolute, or 99.5% water-free, Ethanol is frequently necessary in many organic operations. It is


quite easy to prepare from the azeotrope with water such as "Everclear" brand grain alcohol,
"moonshine" or "Rectified Spirits" (an old term for the same thing).

Dehydrate 75g of fresh anhydrous Calcium Oxide in a vacuum dessicator for 24 hours (a bit
redundant, I know) or heat in an oven at 200C for 2 hours, then immediately transfer to the
vacuum dessicator until use. Setup glassware for simple refluxing with a water-cooled
condenser and a Calcium Chloride guard tube. Place 350mL of Ethanol into the flask, quickly add
the Calcium Oxide and hold at gentle reflux on the water bath or heating mantle for 6 hours.
Allow the mixture to stand overnight, then distill off the alcohol, discarding the first few mL (it
may be more convenient to just vent the condenser to the atmosphere for the first couple of
minutes after distillation has commenced). Yield should be better than 315mL. Store the
absolute Ethanol in a tightly closed glass container as it will pick up water from the air rapidly.

a) Preparation of Ethyl Acetate from Ethanol and glacial Acetic Acid

Dehydrate at least 100mL of grain alcohol to yield absolute Ethanol. 74mL (58g) will be required.
Add this quantity of Ethanol to a round bottom flask with 225g glacial Acetic Acid and 3g of
concentrated Sulfuric Acid. Heat at reflux on an electric heating mantle for 12 hours then attach
a Vigreaux or Hempel fractionating column to distill off the crude ester at 76-77C. Change
receiver flasks and recover the excess of Acetic Acid, bp 118C. Wash the first receiver contents
with a half volume of saturated Sodium Bicarbonate solution then add 50g of anhydrous Sodium
Sulfate (the salt of Sulfuric Acid and Sodium Hydroxide, dried in an oven at >100C for several
hours) and distill the pure dry ester once again. Yield should be greater than 70g.

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