Studies of the Acidity and Ionic Conductivity of Silica-Supported Heteropoly Compounds. I. The Dehydration of <i>t</i>-Butyl Alcohol over Heteropoly Compound Catalysts

Abstract

Abstract The dehydration of t-butyl alcohol (TBA) using various heteropoly compound (HPC) catalysts has been studied. Taking the adsorption of water on the surface of the catalyst into consideration, it is presumed that the dehydration of liquid TBA is governed by a Langmuir–Hinshelwood-like mechanism. Also, the change in the catalytic activity with the amount of HPC supported on the silica suggests that TBA is dehydrated through a pseudo-liquid mechanism in which a few layers of the HPC supported take part in the catalytic reaction. The layer thickness, regarded as a pseudo-liquid phase, depends markedly on the kind of HPC supported. For the dehydration of gaseous TBA, on the contrary, the reaction is found to be of the zero-order; it proceeds through in outer-surface mechanism in which only the outer layer of HPC is effective.