Experimental study of catalyst deactivation and active acid site concentration.

Abstract

Deactivation of catalyst was dealt with from the viewpoint of active site coverage by coke deposition. Catalyst activity and acidity were simultaneously measured in the isomerization of isopentene on commercial silica-alumina catalyst. This revealed that activity of deactivated catalyst was simply dominated by the concentration of Bronsted acid sites remaining available and that the activity at any time relative to the initial time was equal to the fraction of active sites not covered with coke. Based on this simple rule, an n-th order rate expression was justified to properly represent the catalyst deactivation.