Hydrolysis

Hydrolysis (ancient Greek ὕδωρ hydor "water" and λύσις lýsis "solution, dissolution, termination") is the cleavage of a (bio)chemical compound by reaction with water. In this process, a hydrogen atom is (formally) donated to one "cleavage piece", and the remaining hydroxyl moiety is bonded to the other cleavage piece. The reverse of hydrolysis is a condensation reaction. If the solvent in the reaction is also water, the hydrolysis is a solvolysis.

Generally speaking:

Hydrolysis of compound X-Y.

Deviating from the above definition, the term hydrolysis, also called salt hydrolysis, was used by Arrhenius to describe basic or acidic reactions that occur when dissolving salts whose acid or base residues are derived from weak acids or weak bases, respectively. Hydrolysis here is a reversal of neutralization. See also acid-base concept according to Arrhenius.

Examples

• Hydrolysis of alkyl fluorides
• Hydrolysis of carboxylic acid chlorides to carboxylic acids and hydrogen chloride
• Hydrolysis of benzyl chloride to benzyl alcohol and hydrogen chloride
• Hydrolysis of calcium carbide to acetylene and calcium hydroxide
• Hydrolysis of carboxylic acid amides to carboxylic acids
• Hydrolysis of carboxylic acid anhydrides to carboxylic acids
• Hydrolysis of vegetable or animal fats to glycerol and fatty acids
• Hydrolysis of a carboxylic acid ester to carboxylic acid and alcohol
• Hydrolysis of a lactone to the corresponding ω-hydroxycarboxylic acid
• Ester hydrolases catalyze the hydrolysis of one enantiomer of chiral esters to carboxylic acid and alcohol, the other enantiomer is not hydrolyzed
• Hydrolysis of acetals to aldehydes and alcohols
• Hydrolysis of ketals to ketones and alcohols
• Hydrolysis of Grignard compounds
• Hydrolysis of isocyanides
• Hydrolysis of isothiocyanates
• Hydrolysis of nitriles via carboxylic acid amides to carboxylic acids
• Hydrolysis of oximes to carbonyl compounds (aldehydes or ketones) and hydroxylamine
• Hydrolysis of imines to carbonyl compounds (aldehydes or ketones) and primary amines
• Hydrolysis of hydrazones to carbonyl compounds (aldehydes or ketones) and hydrazine
• Hydrolysis of orthocarboxylic acid esters
• Hydrolysis of oxiranes
• Partial hydrolysis of peptides in which only some peptide bonds are cleaved
• Hydrolysis for polyurethane
• Hydrolysis of sulfonyl chlorides
• Hydrolysis of tetrachlorosilane to silicon dioxide and hydrogen chloride
• Hydrolysis of tert-butyl chloride

Most of the hydrolyses listed above proceed better and faster if the reaction is carried out in an acidic or basic medium, rather than at neutral pH. Examples are the acid hydrolysis of esters, which is the reverse reaction to esterification, and saponification, which takes place in a basic medium.

Enantioselective hydrolysis

Esters of chiral carboxylic acids or chiral alcohols can be hydrolyzed enantioselectively under the influence of lipases. Enantiomerically pure alcohols or enantiomerically pure carboxylic acids are formed. Similarly, racemic amides can be hydrolyzed enantioselectively in the presence of acylases. The process is used industrially for the production of the amino acid L-methionine from N-acetyl-DL-methionine.