Organotin-oxometalate coordination polymer catalyzed oxyfunctionalization of monoterpenes

The organotin-oxometalate coordination polymers [(nBu3Sn)2MO4]·nH2O (where, M = Mo or W) were prepared by the interaction of nBu3SnCl with sodium salts of molybdate or tungstate and tested in oxyfunctionalization of monoterpenes with urea hydroperoxide (UHP) as an oxidizing agent. The oxyfunctionalization of monoterpenes gave commercially important products such as epoxides, ketones and hydroxyl derivatives. Among the two catalyst, organotin-oxomolybdate [(nBu3Sn)2MoO4] showed higher activities and epoxide selectivities under selected liquid phase oxyfunctionalization conditions with most of the monoterpenes such as limonene, α-pinene, β-pinene, carene, camphene, gerniol and linalool. The integrity of the organotin-oxometalates polymers were confirmed by X-ray diffraction BET surface area, FT-IR, FT-Raman, SEM, TG/DTA and MAS NMR (13C, 119Sn) analysis. The effects of reaction parameters on limonene conversions and product selectivities have been studied in detail using [(nBu3Sn)2MoO4] catalyst. There was no leaching of the active catalyst into the reaction medium and catalyst was recyclable without loss in its activity in the oxidation reaction.

Graphical abstractThe organotin-oxometalate coordination polymers [(nBu3Sn)2MO4]·nH2O, (where, M = Mo or W) were tested in oxyfunctionalization of monoterpenes such as limonene, α-pinene, β-pinene, carene, camphene, gerniol and linalool with urea hydroperoxide (UHP) as an oxidizing agent in acetonitrile solvent to give high epoxide selectivities of monoterpenes. Figure optionsDownload full-size imageDownload as PowerPoint slide