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, -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.