Effect of Agitation for Mass Transfer in Liquid-Solid Heterogeneous Reaction Systems

Abstract

In this paper, the authors deal with the dissolution of acid anhydride in water followed by the hydrolysis reaction.Classification may be made of the types of reaction taking place, depending upon the relative rates of diffusion and hydrolysis of the acid anhydride.(1) Diffusion resistance is controlling and the over-all rate of reaction depends only on the rate of solution. In this case the higher the agitator speed, the larger the rate of solution.(2) Diffusion resistance and the chemical resistance to hydrolysis are comparable in magnitude. In this case the over-all rate of reaction depends not only on the agitator speed, but also on the rate of hydrolysis.(3) Chemical resistance to hydrolysis is controlling and the over-all rate of reaction is independent of the agitator speed.The authors derived the generalized rate equation and demonstrated the three types of reaction by the hydrolysis reaction of phthalic acid anhydride and benzoic acid anhydride suspended in water under agitation.The authors propose the idea of the "degree of transitional saturation" and the "agitation coefficient for heterogeneous reaction"The latter is useful for the determination of the available agitation intensity for heterogeneous liquid phase reactions.