ABSTRACT

One of the more obvious reasons for the slower reaction rates observed with

the anchored catalyst as compared to the homogeneous catalysts is the fact that hydrogen and substrate diffusion are more important in heterogeneously catalyzed reactions than in those promoted by homogeneous catalysts. Fig. 1 shows the relationship between the turnover frequency (TOF hr-1) and the stirring rate for 1000 TON hydrogenations of DMIT over AHC-Skew. There is possibly some degree of kinetic control in reactions run at 2000 rpm but complete elimination of diffusion control has probably not been attained even at 2400 rpm because of the splashing of solid catalyst particles onto the reactor wall which was observed at the higher speeds. Because of this we believe that with the reactor system used, 2000 rpm is the maximum value reasonably attainable. The product ee’s remained constant at 78-80% and all reactions went to completion.