METHOD OF PREPARING ESTERS Russian patent published in 1998 - IPC

FIELD: chemistry of polymers, more particularly manufacture of polymeric materials. SUBSTANCE: intensified method of preparing esters comprises esterifying dicarboxylic acid or anhydride thereof with alcohol in the presence of titanium containing catalyst which includes tetramethoxy titanium or tetraisopropoxy titanium. Esterification is carried out at 150-170 C and at pressure from 200 to 60 mm Hg. Catalyst amount varies from 0.1 to 13% by weight of reaction mixture, and this amount is introduced in two weight of reaction mixture, and this amount is introduced in two steps: first half of the desired amount at 90-100 C (on dissolution of phthalic anhydride) and remaining 50% is introduced at 150-170 C at pressure from 200 to 600 mm Hg. Tetramethoxy titanium is prepared by transesterification of tetrabutoxy titanium with methanol at 20 C with temperature rise to 55-60 C. Tetrabutoxy titanium is also introduced in two steps: first 0.2-0.26 wt parts of total amount at 20 C, it is then stirred for 1 hour and the remaining portion of tetrabutoxy titanium is then added and temperature is raised to 55-60 C. EFFECT: more efficient preparation method. 2 cl, 1 tbl