Heterogeneous reactions in the liquid phase: Influence of residence time distribution and interaction in the dispersed phase

Abstract

Liquid-liquid reactions and liquid-solid reactions, in systems where the residence time of the dispersed phase does not differ much from that of the continuous phase, are discussed. A method is described for calculating the conversion in continuous one-stage operation from the results of batch experiments for the case in which certain specific conditions are fulfilled. Complications arising in liquid-liquid reactions are considered. One of these is the unpredictability of the degree of dispersion in continuous operation. Another complication is the interaction which occurs in the dispersed liquid phase by the continuous coalescence and redispersion of the dispersed drops. In the case of reactions which take place in the dispersed phase and are of a lower order than unity in the reactant in this phase, the interaction influences the overall conversion favourably. If the reaction is of zero order and an 80% conversion is to be obtained, the reactor volume can be reduced by a factor 3 on account of this influence, providing that the interaction is sufficiently great. The influence of surface-active agents and impurities on the rate of coalescence which is important both for dispersion and interaction, is discussed.