Model esterification of neopentyl glycol and trimethylol propane with 1,4‐tert‐butyl benzoic acid

Abstract 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°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 (KDA = 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.