Abstract The kinetics of the lead ion-catalyzed glycolysis of terephthalonitrile have been studied in the absence of and in the presence of water. In the absence of water, scarcely any formation of β-hydroxyethyl p-cyanobenzoate is observed, but some orthoesters are formed. The reaction rate data obtained in the absence of water are found to fit a reversible consecutive reaction scheme in which some basic compounds are involved as the intermediates. In proportion to the increase in the concentration of water, such intermediates as the orthoesters and basic compounds are hydrolyzed more rapidly to form β-hydroxyethyl p-cyanobenzoate, but simultaneously the hydrolysis of terephthalonitrile and the basic intermediates also takes place in the reaction mixture, thus yielding amide.