The influence of hydrothermal treatment conditions on the structure and catalytic activity of aluminum oxide in the skeletal isomerization of n-butenes

Abstract

In order to obtain an effective alumina catalyst for the n-butenes skeletal isomerization with significant catalytic activity, the authors studied the influence of hydrothermal treatment (HTT) of aluminum oxide-hydroxide system at 150–200 °C on the characteristics of the crystalline, porous structure and acid-base properties of γ-Al2O3, which will be prepared. It is shown that HTT of aluminum hydroxide leads to an increasing of crystallites size, decreasing specific surface Al2O3 area, as well as reducing the number of acid-base centers, what resulting in catalyst activity lowering. HTT of phase system «alumina–aluminum hydroxide» gives smaller γ-Al2O3 crystallites, which leads to increasing the acidity of Al2O3 which formed after calcination at 550 °С, and, consequently, to increasing in catalytic activity. This method can be used to enhance the activity of industrial samples of aluminum oxide in the reaction of n-butenes skeletal isomerization.