Process for the preparation of the 5-nitro-isophthalic-di- C1-C4-alkyl esters

摘要

Preparation of a di-(1-4C) alkyl isophthalate (I) comprises: (i) dissolving or suspending 5-nitroisophthalic acid (II) in a mixture of a 1-4C alcohol (III) and a solvent which is immiscible or only partially miscible with water; (ii) heating in the presence of a strong acid to form a second aqueous phase; (iii) when the reaction is complete crystallising obtained (I) from the organic phase by cooling; and (iv) separating the aqueous phase, either before or after separation of (I).