Zeolite-based catalysis for isobutene conversion into chemicals and fuel additives. A review

Isobutene (IB), the most reactive molecule in the C4 raffinate, is a raw material of great industrial significance. It is extensively used in the manufacturing process of rubber, fuel additives, fine chemicals, agricultural chemicals, plastics and antioxidants. Heterogeneous catalysts and par-ticularly zeolites are playing a major role in these applications. The aim of this review is to examine the relevant processes involving IB as reagent and zeolites as acid catalysts. The following reactions are successively covered: Prins condensation, IB dimerization, IB-methanol/ethanol etherification, IB-glycerol etherification, IB amination, and phenol tert-butylation. While reasonably comprehen-sive and broad, the present survey is not necessarily exhaustive. The mechanistic aspects of the titled reactions, the role of zeolite catalysts and their topology/active sites on the product selectivity are mainly explored.