Mass-transfer enhancement and reaction-rate limitations in solid-liquid phase-transfer catalysis

Abstract

We present an analysis of mass transfer in solid-liquid phase-transfer catalysis (SLPTC), obtaining analytical solutions for the stagnant-film model and numerical solutions to the complete transport equations for the von Kármán rotating-disk flow. The latter is viewed as a prime candidate for experimental studies on SLPTC. A catalyst-effectiveness plot is developed, which displays both mass-transfer enhancement and reaction-rate limitation associated with the two distinct Damköhler parameters for the bulk and surface reactions. Solutions are obtained from the film model for pseudo-first-order reaction and for rapid equilibrium reaction, including irreversible reaction with flame-like reaction fronts. Comparison of stagnant-film model against the numerical solutions for the rotating disk shows generally good agreement, as one would expect for uniformly accessible surfaces.