Reaction and deactivation study of mesoporous silica–alumina (MSA) in propene oligomerisation

Abstract

Deactivation of mesoporous silica–alumina (MSA) is investigated in propene oligomerisation. The initial activity is correlated with the Lewis acid sites. Part of them is poisoned at the beginning of the reaction, the decay rate being consistent with their strength. At longer reaction time pore blockage, caused by an increased dimension of the adsorbed organic residues, becomes the main side phenomenon. The deactivation of mesoporous silica–alumina (MSA) catalyst was investigated in the propene oligomerisation. Three catalysts with different acid site distribution were synthesised and tested, in order to determine the role of the acid sites in both main and side reactions. The initial activity is correlated with the Lewis acid site density. A two-stage mechanism for deactivation has been proposed. At the beginning of the reaction, poisoning of the active site takes place, the decay rate being consistent with the strength of the Lewis acid sites. At longer reaction time pore blockage, caused by an increasing of the dimensions of the adsorbed organic residues, becomes the main side phenomenon.