Liquid-Liquid and Solid-Liquid Reactions
Chapter 14 was concerned with gas-liquid reactions, although it was mentioned at the beginning of the chapter that the same principles would apply equally if phase 1 were a liquid or a solid. The premise for such a statement was that phase 1 comes into the picture only to the extent that it supplies the solute A that diffuses into phase 2 and reacts with B in the film, bulk, or both, in that phase only. Because the state of phase 1 is immaterial in such a situation, the theories are equally applicable when the phase is a liquid or a solid. However, an additional factor comes into play when phase 1 is also a liquid. Component B from phase 2 can have a finite solubility in phase 1, diffuse into that phase and react there with A. Thus reaction can occur in both phases. This is equally true when phase 1 is a solid, but the mechanism of diffusion and reaction in a solid is different. It is also possible for a gas and a solid to simultaneously dissolve and react in a liquid, but as three phases are involved here, it is considered in Chapter 17. In this chapter we consider the following two classes of reactions: liquid-liquid and solid-liquid. One encounters reactions belonging to these classes quite frequently in organic chemical technology. We shall give instances of these while dealing with the individual systems. Hydrolysis and saponification of esters and fats (Jeffreys et al., 1961; Donders et al., 1968; Sharma and Nanda, 1968), sulfonation and nitration of aromatic compounds (Albright and Hanson, 1969, 1975; Hanson and Ismail, 1976; Barona and Prengle, 1973), alkylation of isobutane, toluene, and phenols with isobutylene (Jernigan et al., 1965; Mosby and Albright, 1966; Sprow, 1969; Tiwari and Sharma, 1977; Zaldivar et al., 1996), and oximation of cycloyhexanone (Rod, 1974, 1976) are some of the liquid-liquid reactions in which reaction occurs in both phases. The reaction last mentioned between cyclohexanone (which constitutes the organic phase) and aqueous hydroxylamine sulfate (containing ammonium sulfate) to give cyclohexanone oxime comprises the first step in the manufacture of caprolactam, an important reactant in the synthesis of Nylon.