Esterification reaction

Claim 1

The process of producing relatively pure esters, which comprises reacting a solution of at least one organic polycarboxylic acid compound selected from the group consisting of phthalic acid, phthalic anhydride, isophthalic acid, terephthalic acid, 2,5-dibromoterephthalic acid, trimellitic anhydride, trimellitic acid, adipic acid, adipic anhydride, and sebacic acid in the presence of a tetraalkyl titanate esterification catalyst in excess monohydroxy hydrocarbon compounds selected from the group consisting of alcohols containing from 1 to 24 carbon atoms and aromatic hydroxy compounds containing 6 to 18 carbon atoms to produce a monohydroxy solution of organic ester, treating the dissolved organic ester in the substantial absence of unbound water at a temperature of at least 120° C with at least one solid alkaline earth metal compound selected from the group consisting of alkaline earth metal oxide and alkaline earth metal hydroxide, adding subsequently two to twenty mols of water per mol of alkaline earth compound to the dissolved ester at up to 100° C and partitioning solid alkaline earth metal compound from the dissolved organic ester, wherein the concentration of alkaline earth metal compound is 0.1 to 35 equivalents per equivalent of acid material in the monohydroxy solution of organic ester.