Florol synthesis via Prins cyclization over hierarchical beta zeolites
Résumé
A set of hierarchical beta zeolites with variable Si/Al ratios, nanoparticle sizes, textural and acidic properties was prepared using a hydrothermal treatment of a concentrated alkali metal-free protic acid-containing zeolite gelprecursor. The obtained catalysts were investigated in the Prins cyclization of isovaleraldehyde with isoprenol yielding a commercially valuable tetrahydropyranol (Florol). The highest yield of the desired product (55.4%) was achieved over a zeolite catalyst possessing moderate acidity, developed mesoporosity (V meso 0.60 cm 3 /g) and a high external surface area (290 m 2 /g). Preferable formation of substituted tetrahydropyranol over weakand medium-strength Brønsted acid sites, on the one hand, and generation of the undesired dehydration products mainly over strong Brønsted acid sites, on the other hand, occurring in parallel routes were supported by the kinetic analysis of the reaction network.
Domaines
Chimie théorique et/ou physiqueOrigine | Fichiers éditeurs autorisés sur une archive ouverte |
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