Production of dialkyl maleate from a mixture comprising a mondalkyl maleate

Abstract From the Canadian patent

PROCESS, A continuous process is described for the production of a substantially acid free dialkyl maleate for example diethyl maleate, from a feed stream containing a major amount of dialkyl maleate and a minor amount of the corresponding monoalkyl maleate. This comprises continuously distilling the feed stream in a primary distillation zone, which can comprise a single distillation column or a series of distillation columns connected in series, so as to give (i) a bottom fraction containing monoalkyl maleate and dialkyl maleate in admixture, (ii) a vaporous fraction comprising alkanol and (iii) an intermediate fraction that is substantially free from alkanol and comprises a major …