Production of diesters from dinitrile compounds

A process for the preparation of at least one diester compound comprising the following stages:

• a) first preparing an imide compound of the following general formula (I):
• wherein A is a linear or branched divalent hydrocarbon radical having from 2 to 12 carbon atoms,
• by hydrolysis, in the presence of water, of at least one dinitrile compound of following general formula (III):
• NC-A-CN (III)
• and b) then reacting said imide compound with at least one alcohol of the following general formula (II):
• R—OH (II)
• wherein R is a linear or branched aliphatic, cycloaliphatic, aromatic or arylalkyl hydrocarbon radical having from 1 to 20 carbon atoms and optionally containing heteroatoms,
• to obtain a reaction product comprising at least one diester compound of the following general formula (IV) and optionally by-products of different formula (e):
• R—OOC-A-COO—R (IV)
• wherein:
• at least one of the stages a) and/or b) is carried out in the presence of a catalyst, with the proviso that if both stages are carried out in the presence of a catalyst, then stage b) is carried out in the presence of at least one catalyst other than that employed during stage a).