Sucrose inversion catalyzed by macroreticular ion exchange resins

Abstract

A two-phase (spherical microparticles and pores formed by space between them) model was proposed to account for reaction and diffusion inside a macroreticular ion exchange resin catalyst. The active sites were uniformly distributed over the pore walls as well as in the microspheres and reaction occurred on both phases. The model could be considered as a generalization for a bidisperse catalyst model where reactions on the pore walls were negligible. The overall effectiveness factor, expressed in terms of the micro- and macroeffectiveness factor and the fraction of the active sites located on the pore walls, was obtained analytically for a first-order reaction and numerically for a second-order one. Applicability of the present model has been examined through performing the sucrose inversion in a batch reactor by using two types of macroreticular ion exchange resins, i.e., Amberlyst 15 and Amberlyst XN-1010. It was shown that the inversion reaction was apparently of first-order. While the effect of particle size, reaction temperature and resin amount were investigated, the data on the initial reaction rates were found to be in a good correlation with the model. The parameters obtained through correlation had reasonable values. However the resin catalyst were observed to be less effective than the homogeneous acids such as hydrochloric acid and p-toluenesulfonic acid, which seemed to be due to the difficulty in diffusion of sucrose molecules through the resin matrix.