Pimelic and subaric acids were esterified to the resp. diesters with cyclohexanol in presence of H2SO4 in a lab. isothermal semibatch reactor at 120-150 degrees C (alc.-to-acid ratios 3:1 to 10:1) to study the reaction kinetics. The reaction had 2-step course. The formation of resp. monoesters was 1st order reaction with respect to the acid and the formation of diesters was 1st order reaction with respect to monoester. The activation energy of monoester formation was substantially higher than that of diester formation.