Triplet Calorimetry at Rising Temperatures for Rapid Analysis of Lipuid Phase Reaction Kinetics

Abstract

To obtain the temperature dependency of reaction kinetics and heat of reaction in liquid phase from single experiment instead of several runs at various temperatures, a new calorimetry that is carried out with the " Triplet Calorimetry" operated at rising temperatures is developed. The calorimeter consists of three equivalent jacketed-vessels (1000 ml stainless autoclaves) each of which has an agitator, a thermocouple and an internal heater. The first is used for reference, the second for reaction analysis, and the third for compensation of equipmentfactors by means of periodic step responses with the internal heater during the reaction. The heat transfer medium is heated at constant rate and is recycled through medium heater and each jacket. Film coefficient of outer side of vessel wall may be influenced by the effect of rising temperatures. So the coefficients of three vessels must be equal with one another by means of flow control of the medium. Applying this calorimetry to the analysis of hydration of acetic anhydride in 70% aqueous acetic acid solution, Q = 13.60 ± 0.5 kcal/mol and k= 7.89 x 107 exp (-15.8 x 103/R T) sec-1 under n=1 were obtained in the range of 20-40° C.