Highly efficient epoxidation of styrene and α-pinene with air over Co2+-exchanged ZSM-5 and Beta zeolites

Co2+-exchanged zeolites (prepared simply by ion-exchange method) have been used in the epoxidation of styrene and α-pinene with air, in which Co-ZSM-5 and Co-Beta without any organic Schiff-base ligand or additive behaved as highly efficient catalysts. Co-ZSM-5 and Co-Beta achieved 88.4–92.4 mol% conversion with the overall selectivity of 94.6–96.6% for the epoxidation of styrene, and 92.8–90.6 mol% conversion with the selectivity of 86.1–88.3% for the epoxidation of α-pinene, respectively. Recycling studies and control experiments showed the stability and recyclability of Co-ZSM-5 and Co-Beta in the epoxidation reaction.

Graphical abstractSimple Co2+-exchanged ZSM-5 and Beta present highly catalytic epoxidation activity. Co-ZSM-5 and Co-Beta achieve 88.4–92.4 mol% conversion of styrene with the overall selectivity of 94.6–96.6% for styrene oxide, and 92.8–90.6 mol% conversion of α-pinene with the selectivity of 86.1–88.3% for α-pinene oxide, respectively.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Co-ZSM-5 and Co-Beta are prepared by a simple ion-exchange route. ► Both show high activities for the epoxidation of styrene and α-pinene with air. ► These solids are highly reusable heterogeneous catalysts.