11. Interfacial Mechanism and Kinetics of Phase-Transfer Catalysis

tively. When the amount of the third liquid phase has little effect on the overall reactionrate, the contribution of greater amounts of third liquid phase is to increase the masstransfer resistance. This case is similar to the situation of a very thin film of the third phasewith =R 1. They also proposed an equation [235] for the concentration of benzylchloride using the analogous analytical solution of heat transfer in terms of a mass transferproblem asC BC ¼ X1n¼1A n exp 2 n sinð n Þ n ð199Þwhere the eigenvalues n and the coefficients A n are given by1 n cotð n Þ¼N D and A n 4sinð ½ nÞ n cosð n ÞŠ2 n sinð2 n Þð200ÞVI.CONCLUSIONIn recent years, researches in PTC have achieved great progress in the development of thebasic theory and applications; the number of publications and patents in PTC has grownsteadily during the past decade. Halpern [236] estimated that the 5-year average of TBABpatents issued per year was 38 in 1985, 46 in 1990, and 57 in 1995. The PTC publicationsfor a 5-year average issued per year are 389 in 1985, 467 in 1990, and 484 in 1995. Thisinformation indicates the potential applications of PTC in industries either revamping ordeveloping new processes, including the applications of PTC in biology.The aspects of PTC publications were mostly concentrated in chemistry-based investigationsin past years. On viewing the nature of PTC, the presence of immiscible phasesand the transport of reacting species between the phases are the basic phenomena; therefore,the mass transfer resistances at the interface and within the intraphase should betaken into account in accompanying the chemical reactions for the purpose of reactordesign. The engineering analysis in various types of PTC, together with other techniquesfor enhancing the overall reactivity, has the advantage of realizing the factors influencingthe observed reaction rate, which makes the process design closer to the inherent results. Itis hoped that the review in this chapter could serve to generate more applications of PTCin the future.Copyright © 2003 by Taylor & Francis Group, LLC