Process for the production of dialkyl maleates

A process according to claim 34, in which monoethyl maleate produced in the monoesterification zone is reacted with ethanol in a primary esterification zone containing a charge of a solid esterification catalyst, and in which the resulting intermediate esterification product mixture is distilled in a first distillation step to separate a mixture containing ethanol and water from a mixture containing mono- and di-ethyl maleates, which mixture is used as the first liquid feed to said secondary esterification zone, if there is only one secondary esterification zone, or to the first one of said secondary esterification zones, if there is more than one said esterification zone.

A process for the production of a dialkyl maleate which comprises:

• (a) reacting maleic anhydride with an alkyl alcohol in a monoesterification zone to form monoalkyl maleate;
• and
• (b) reacting with monoalkyl maleate said alkyl alcohol to form dialkyl maleate, wherein a first liquid feed comprising said monoalkyl maleate is supplied to a secondary esterification zone containing a charge of a solid esterification catalyst, a second feed stream comprising said alkyl alcohol is supplied to said secondary esterification zone, said secondary esterification zone being maintained at an elevated temperature sufficient to form or maintain therein a vaporous stream containing said alkyl alcohol, said first liquid feed is intimately contacted with said vaporous stream in said secondary esterification zone in the presence of said catalyst, a vaporous effluent stream is recovered from said secondary esterification zone containing in addition to alkyl alcohol vapour, also water in vapour form, said water being produced in said secondary esterification zone by esterification of said monoalkyl maleate with said alkyl alcohol, and a liquid product containing said dialkyl maleate, is recovered from the secondary esterification zone.