Crotonic acid

Crotonic acid produced industrially by oxidation of crotonaldehyde: : Furthermore, it is formed during the distillation of 3-hydroxybutyric acid: : ==Properties==

Crotonic acid crystallizes in the monoclinic crystal system in the space group P21/a (space group 14, position 3) with the lattice parameters , , and . The unit cell contains four formula units. ==Reactions==

Crotonic acid converts into butyric acid by hydrogenation or by reduction with zinc and sulfuric acid. : Upon treatment with chlorine or bromine, crotonic acid converts to 2,3-dihalobutyric acids: : The reaction with alkaline potassium permanganate solution affords 2,3-dihydroxybutyric acid. Esterification of crotonic acid using sulfuric acid as a catalyst provides the corresponding crotonate esters: : Crotonic acid reacts with hypochlorous acid to 2-chloro-3-hydroxybutyric acid. This can either be reduced with sodium amalgam to butyric acid, can form with sulfuric acid 2-chlorobutenoic acid, react with hydrogen chloride to 2,3-dichlorobutenoic acid or with potassium ethoxide to 3-methyloxirane-2-carboxylic acid. : Crotonic acid reacts with ammonia at the alpha position in the presence of mercury(II) acetate. This reaction provides -threonine. ==Use==

Crotonic acid is mainly used as a comonomer with vinyl acetate. : ==Safety==

Its is 1 g/kg (oral, rats). It irritates eyes, skin, and respiratory system. == See also ==