MODEL ESTERIFICATION OF NEOPENTYL GLYCOL AND TRIMETHYLOL PROPANE WITH 1,4-TERT-BUTYL BENZOIC-ACID

The esterification kinetics of difunctional neopentyl glycol and trifunctional trimethylol propane with monofunctional 1,4-tert-butyl benzoic acid was studied in the melt phase at 200-degrees-C in the presence of a metal catalyst. The rate of conversion was monitored via titrations and by determination of the relative concentrations of products and reactants using HPLC with a UV detector. A small but significant positive substitution effect was found for neopentyl glycol (K(DA) = 1.15) and none was found for trimethylol propane. The reaction rate constant of neopentyl glycol with the acid is about 40% higher than that of trimethylol propane with the acid. A second-order overall reaction order was used to compute the rate constants.