Readily available Ti-beta as an efficient catalyst for greener and sustainable production of campholenic aldehyde

Abstract

Different Ti-beta zeolite samples were prepared following a convenient and optimized post-synthetic route and starting from commercial Al-beta zeolite. Lewis acid sites have been successfully incorporated into vacant tetrahedral (T)-sites of a dealuminated beta-framework by ball-milling solid-state ion-exchange. A tribology-ball milling process was used in order to increase the interaction between dealuminated-beta zeolite and the Ti-precursor. Thermal treatments with water and aqueous solution of NaNO₃ or Li NO₃ allowed optimization of the catalytic properties of the Ti-Lewis active sites which exhibited excellent catalytic activity and stability for the isomerization of α-pinene oxide into campholenic aldehyde in both batch and fixed bed reactor systems. Additionally, the catalytic performance of the post-synthesised Ti-beta zeolite was compared to a Ti-beta zeolite prepared in fluoride media. From different points of view such as preparation of readily, highly active, selective and stable catalysts, throughput, sustainability and cost, herein we report the selective solid catalysed α-PO isomerization with excellent results, 88% selectivity and yield, a CA production of 225 g g_cat⁻¹ h⁻¹ and new opportunities.