Prepared By : Enrollment No

Ethanol By Hydrolysis

Properties of Ethanol  Ethanol is a colourless liquid with a pleasant smell.  It is completely miscible with water and organic solvents and is very hydroscopic.  Ethanol is a monohydric primary alcohol.  Ethanol forms of constant – boiling mixture, or azeotrope, with water that contains 95% Ethanol nd 5% water.

 Ethanol burns in air with a blue flame, forming carbon dioxide and water.  Ethanol that is completely free of water is called absolute ethanol.  Absolute ethanol cannot be obtained by simple distillation.

Raw materials Ethylene Water  Catalyst : Phosphoric Acid

Procedure  The production of Ethanol by the direct additive of water to ethylene is being carried out successfully on a commercial scale.  In the shell process a phosphoric acid used as catalyst in the reaction.  The reaction section is shown in fig. A several parallel units. The feed ethylene joining the large recycle stream.

Chemical Reaction

 After entering the tap of the reactor the feed passes downward through the catalyst bed where a fraction of the mixture is converted to ethyl alcohol.  Since the reaction is exothermic the product leaving the reactor is at a higher temperature than the feed.  After washing with dilute caustic soda to neutralize traces of phosphoric acid if passes into a second exchanger and on to a high pressure separator to give a liquid and a vapour stream.

 The condensate goes to purification and the vapour to recycle. The vapour is cooled by the recycle gas cooler and scrubbed with water to remove alcohol.  The build up of impurities like methane and ethane is controlled at this point by venting a small stream of the recycle.  The condensate and the alcohol water solution of the various parallel units are combined and separated in a low pressure separator.

 A recycle hydrogen stream is combined with the alcohol before it enters the treater. In the treater traces of aldehydes are hydrogenated to over a supported nickel catalyst to the corresponding alcohols.  The product from this reactor is condensed separated and sent to the light ends column where light by products, primillary diethyl ether are taken overhead.  Product ethanol is removed as a side stream from the final purification column.

Uses of Ethanol  Ethanol is used extensively as a solvent in the manufacture of varnishes and perfumes.  Used as a preservative for biological specimens.  Use in beverage industries.  Used in medicines.  Cosmetic products.  Used in production of acetic acid.

Sources of Pollution  Spilling of alcohol leads to fire hazards.  Ethanol boom leads to increase smoke.  Ethylene pollution influences the activities of plant hormones and growth activity.

Health And Safety  Keep away from flame.  Ventilate valve and avoid breathing vapours.  Use appropriate extinguishing media for surrounding fire.  Wear approved chemical safety goggles.