Hydrolytic processes

Hydrolytic processes

Reactions of both organic and inorganic chemistry wherein water effects a double decomposition with another compound, hydrogen going to one component, hydroxyl to another, as in reactions

(1)–(3). Although the word “hydrolysis” means decomposition by water, cases in which water brings about effective hydrolysis unaided are rare, and high temperatures and pressures are usually necessary.

Hydrolytic reactions may be classified as follows: (1) hydrolysis with water alone; (2) hydrolysis with dilute or concentrated acid; (3) hydrolysis with dilute or concentrated alkali; (4) hydrolysis with fused alkali with little or no water at high temperature.

In the field of organic chemistry, the term “hydrolysis” has been extended to cover the numerous reactions in which alkali or acid is added to water. An example of an alkaline-condition hydrolytic process is the

hydrolysis of esters, reaction (4), to produce alcohol. An example of an acidic-condition process is the hydrolysis of olefin to alcohol in the presence of phosphoric acid, reaction (5). The addition of acids or alkalies hastens
such reactions even it it does not initiate the reaction.

Perhaps some of the oldest and largest-volume hydrolysis technology is involved in soap manufacture. In the first step, glyceryl stearate acid, a fat, is hydrolyzed with water to yield stearic acid and glycerin. In the second step, the stearic acid is neutralized with caustic soda to give sodium stearate, the soap, and water.

Hydrolytic processes account for a huge product volume. Conversion of starch such as corn starch into maltose and glucose (sugar syrups) by treatment with hydrochloric acid is a major industry. Similarly, the production of furfural from pentosans of oat hulls or other cereal by-products such as corn cobs, rice hulls, or cottonseed bran is another commercial hydrolytic process.

McGraw-Hill Concise Encyclopedia of Engineering. © 2002 by The McGraw-Hill Companies, Inc.
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