SnO₂–SiO₂ Mesoporous Composite: A Very Active Catalyst for Regioselective Synthesis of Aromatic Ketones with Unusual Catalytic Behavior

Abstract

Aromatic ketones (R-Ar-CO-R′) have been prepared directly through C-C bond formation using aromatics, aryl, and alkyl acid halides to undergo Friedel-Crafts reaction over reusable and catalytically active ordered SnO 2 -SiO 2 three-dimensional mesoporous composite (PS-4) catalyst, which found to be superior to modified zeolites, functionalized MCM-41 and supported heteropolyacid catalysts.

Nanocrystallite Zeolite BEA for Regioselective and Continuous Acetyl Functionalization of Anisole Using Acetic Anhydride: Catalyst Deactivation Studies

“…Heterogeneous solid acid catalysts were identified as eco-friendly and promising catalysts for Friedel–Crafts acylation reactions because of their tailorable acidity, pore topology, tunable textural properties, high thermal stability, trouble-free handling, easy separation from reaction media, a lower amount of catalyst requirement, and reusability for multiple times after regeneration. Various three-dimensional solid acid catalysts such as mesoporous silica, − heteropolyacids, , H-MFI, H-FAU, H-BEA, − and H-MOR , have been extensively examined for catalytic activity studies on acylation of anisole under various ranges of process parameters in the batch reactor. Among the solid acid catalysts mentioned above, zeolite beta (BEA) is considered as a prominent catalyst for the acylation of anisole because of its divertive strong acidity originating from a structural framework constituted by two polymorphs and interconnecting channels with a high concentration of structural defects, − which provides a higher level of anisole conversion, and also its pore topology oriented toward the regioselective formation of 4-MAP. − Synthesis of organic compounds over solid acid catalysts often suffers from rapid catalytic deactivation because of their strong interaction with oxygenated products, dealumination, and trapping of heavier molecular weight products in micropores/mesopores or on the intercrystalline surfaces because of their diffusion limitation. ,,,− A deactivated catalyst always needs to undergo catalyst regeneration, which triggers an increase in the process economics and yield loss and imposes technical complexities.…”