METHOD OF PHTHALATES SYNTHESIS Russian patent published in 1994 - IPC

FIELD: chemical technology. SUBSTANCE: ester is synthesized by alcohols esterification with phthalic anhydride at 150-250 C, under pressure from 101,3 to 2,7 kHa in the presence of titanium-containing catalyst. Reaction water and alcohol are distilled off. The latters then are distilled in fractionating column, and condensate is separated for aqueous and spirituous phase. Aqueous phase is used partially for reflux in fractionation, and 10-50% is fed directly into reaction zone. Then ester-raw is purified from acidic components and excess of alcohol by treatment with sorbents and filtration. Yield of the end product is 99,2% , color index is decreased from 60-120 to 60 units after 20 cycles. EFFECT: increased stability of process, enhanced quality of the end product. 1 tbl