The Hydrothermal Activation of Silica–Alumina for Butene Isomerization. A Device to Prepare a Standard Sample

Abstract

Abstract Three kinds of silica–alumina catalysts were prepared by hydrothermal treatment (heating a sample in hot water) over the range of 25–250 °C for various periods. It was found that the hydrothermal treatment significantly increased its catalytic activity for butene isomerization. The dependencies of various surface properties (the production ratio of 2-butene isomers, the surface acidity, the surface area, the pore-size distribution, and the shape and size of the catalyst particle) on the hydrothermal conditions and the kind of starting catalyst sample were systematically investigated, too. It was concluded that the increase in the catalytic activity might be due to the progress of the Si/Al isomorphic substitution in the tetrahedral surface silica network. Hot water might serve as a solvent for the cations and facilitate their movements. Since the hydrothermal treatment can erase the effects of the blending method on the catalytic activity and other surface properties almost completely, this treatment can be used to prepare a standard sample.