Fumarate prepn from maleates - by heating with ammonium chloride or carbonate as catalyst

摘要

Maleate rearrangement to fumarates, useful in prodn. of polyester resins, copolymers and in paint and varnish industry, is effected below 180 degrees C, pref. of 100-150 degrees C, using NH4 Cl or (NH4)2CO3 as catalyst. Pref. conversions include isomerisation od dimaleates of difumarates and or monomaleates to monofumarates and opt. their further esterification to difumarates. Monomaleates used may be prepd. by reacting maleic anhydride with an alcohol in the presence of NH4Cl.