Epoxidation of bulky organic molecules over pillared titanosilicates

• A pillared TS-1 catalyst was prepared from nanosheet TS-1.
• Addition of titanium to the pillaring mixture improves the catalyst performance.
• The pillared TS-1 catalyses the epoxidation of terpenes.
• Selective oxidation of verbenol to verbenone was observed.

Layered and pillared TS-1 catalysts were prepared using surfactant C18H37–N+(CH3)2C6H12–N+(CH3)2C6H13 in the hydroxide form as a structure directing agent and silicon(IV) ethoxide or its mixture with titanium(IV) butoxide as a pillaring medium. The pillaring treatment significantly increases the specific surface area (BET up to 685 m2/g) and thus the accessibility of active centres for bulky molecules. The addition of tetrabutylorthotitanate into the pillaring mixture has a positive effect on the material performance as a catalyst of cyclooctene, norbornene and α-pinene epoxidation under mild conditions, with hydrogen peroxide as the oxidant. Optimum composition of the pillaring medium is Si/Ti ratio 20. The highest yields of cyclooctene oxide (16.9% after 4 h) and norbonene oxide (14.8% after 4.5 h) were obtained using the above-prepared catalyst at 60 °C with substrate/catalyst mass ratio being 10 and substrate/H2O2 ratio being 2. Selective oxidation of verbenol to verbenone was observed instead of the epoxidation with the above catalysts.

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