Selectively catalytic epoxidation of styrene with dry air over the composite catalysts of Co-ZSM-5 coordinated with ligands

• Published in: Journal of molecular catalysis. A, Chemical Vol. 266; no. 1; pp. 180 - 187
• Main Authors: Xu, G., Xia, Q.-H., Lu, X.-H., Zhang, Q., Zhan, H.-J.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 02-04-2007; Elsevier
• Subjects: Air; Catalysis; Chemistry; Co-ZSM-5; Exact sciences and technology; General and physical chemistry; Ion-exchange; Ligand; Styrene epoxidation; Surface physical chemistry; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; Zeolite composite catalyst; Zeolites: preparations and properties; Styrene epoxidation; Zeolite composite catalyst; Air; Co-ZSM-5; Ligand; Catalytic reaction; Hydrocarbon; Transition metal; Cobalt; Composite material; Molecular sieve; Heterogeneous catalysis; Styrene; Epoxidation; Benzenic compound; Catalyst
• ISSN: 1381-1169; 1873-314X
• DOI: 10.1016/j.molcata.2006.10.052

The catalytic activity of composite catalysts of Co-ZSM
-5 coordinated with ligands for the selective epoxidation of styrene with dry air was studied in the temperature range of 50–100
°C under atmospheric pressure. The catalyst Co-ZSM-5(
L
2
) containing vanillic aldehyde salicylhydrazone (
L
2
) exhibited the best activity and selectivity for the epoxidation; e.g. 96.9
mol% of styrene conversion with an epoxide selectivity of 94.0% as well as a low benzaldehyde selectivity of 3.1% was attained when the concentration of styrene in solvent was 0.2
mmol/g. Over the composite catalysts of Co-ZSM
-5 coordinated with ligands, the overall selectivity of the epoxide (styrene oxide) plus the corresponding isomer (phenylacetaldehyde) was higher than 90%. It is noteworthy that the use of TBHP in small amounts efficiently initiated the reaction, and the lack of TBHP led to a low conversion and selectivity.