Hierarchical Beta Zeolites As Catalysts in α-Pinene Oxide Isomerization

Hierarchical beta zeolites obtained in the concentrated reaction mixtures (H2O/Si = 2.5) and micromesoporous materials synthesized using a dual-template approach from a zeolite beta precursor were rigorously characterized and tested in a sustainable and environmentally friendly process of a-pinene oxide isomerization. The highest yield of trans-carveol (42%) with chemopreventive activity of mammary carcinogenesis was achieved over low crystalline micromesoporous materials characterized by well-developed mesoporosity, an increased fraction of weak-to-medium Bronsted acid sites and low Bronsted and Lewis acid sites (BAS/LAS) ratio. In turn, highly crystalline hierarchical beta zeolites with a lower mesopore volume and the mesopore surface area, stronger Bronsted acidity, and a higher BAS/LAS ratio favored the formation of campholenic aldehyde (31% yield). The mechanism of the desired product and byproducts formation was discussed and its feasibility was confirmed by kinetic modeling.

Automated summary

In this study, hierarchical beta zeolites and micromesoporous materials were characterized and tested for a-pinene oxide isomerization. It was found that low crystalline micromesoporous materials favored the production of trans-carveol, while highly crystalline hierarchical beta zeolites favored the formation of campholenic aldehyde.