METHOD OF OBTAINING ISOPHTHALIC ACID OF MONOMERIC PURITY

摘要

The invention pertains to industrial organic and petrochemical synthesis, in particular to a continuous process for producing isophthalic acid of monomeric purity. An industrial process is proposed by which the quality of the isophthalic acid is improved and unit wastage of acetic acid reduced by a combination of two interdependent processes for oxidation and recrystallisation in a single water-acetic acid solvent. The oxidation process is carried out in a cascade of two reactors arranged in series at moderate temperatures of 180-199 DEG C in the presence of a catalyst comprising a mixture of metals Co, Mn, Ni, Na, Li and K and a mixture of bromine compounds containing ionic and covalent bonds, under experimentally established conditions. The mother liquors are recirculated once the raw (filtrate 1) and pure (filtrate 2) isophthalic acids have been separated out during the first and second oxidation stages respectively.