Working up reaction mixture containing malonic diester, useful in synthesis, from carbonylation and esterification of haloacetic ester includes isolating ester by washing organic phase and crystallizing alkali halide useful in electrolysis

摘要

Working up reaction mixtures from reaction of haloacetic esters with carbon monoxide, monohydric alcohol and base in presence of transition metal catalyst by contact with aqueous acid and oxidant, phase separation and aqueous extraction, isolates malonic diester by washing the organic phase. Aqueous phase is worked up by precipitating transition metal and crystallizing alkali halide. In a process for working up reaction mixtures from the carbonylation of haloacetic esters of formula R1O-C(=O)-CH2-Hal (II) with carbon monoxide and reaction with a monohydric alcohol of formula R2-OH (III) and a base in the presence of transition metal catalyst by contact with aqueous acid and an oxidant, followed by phase separation, the resultant aqueous phase is extracted and the combined organic extracts and organic phase are washed to isolate the malonic diester of formula R1O-C(=O)-CH2-C(=O)-OR2 (I). R1, R2linear or branched, (un)saturated 1-16 carbon (C) alkyl, aryl or an alkylaryl or aralkyl group with 1-5 (1-6 C alkyl) substituent(s); Hal : halogen. The transition metal is isolated from the aqueous phase as hardly-soluble hydroxide or carbonate, then the aqueous phase is freed from residual traces of transition metal and alkali halides are recovered, with or without thermolysis in acid medium, by evaporation and crystallization at pH less than 7 and normal or reduced pressure.