Production of dihydro-diketo-isophorone, used e.g. in Vitamin E acetate synthesis, involves epoxidation of beta-isophorone with organic percarboxylic acid followed by in-situ isomerization of initial products

摘要

Production of dihydroketoisophorone comprises reaction of beta -isophorone with an organic percarboxylic acid. The mixture of initially-formed beta -isophorone epoxide and isomeric 4-hydroxyisophorone is isomerized in situ either thermally or in presence of an acid catalyst or a salt. Production of dihydroketoisophorone (2,2,6-trimethylcyclohexane-1,4-dione) (I) comprises reaction of beta -isophorone (3,5,5-trimethylcyclohex-3-en-1-one) (II) with an organic percarboxylic acid in the form of a non-aqueous solution, at 0-200 deg C in an inert organic solvent. The per-acid is formed in a separate equilibrium reaction and absorbed or extracted with the oxidation solvent. The mixture of initially-formed beta -isophorone epoxide (III) and isomeric 4-hydroxyisophorone (HIP) (IV) is isomerized in situ either thermally or in presence of an acid catalyst or a salt.