Direct oxidative esterification of alcohols catalyzed by a nitrogen-doped carbon black-supported PdBi bimetallic catalyst under ambient conditions

摘要

A highly efficient nitrogen-doped carbon black (NCB)-supported PdBi alloy nanocatalyst has been fabricated via a facile coreduction wet chemical approach. The optimal PdBi/NCB shows outstanding catalytic performance with broad substrate scope, good functional group tolerance towards direct oxidative esterification of alcohols under mild conditions in a heterogeneous catalytic system with air as the sole oxidant. A variety of benzylic and allylic alcohols were smoothly reacted with methanol and even with long-chain aliphatic alcohols, providing desired esters in good to excellent yields. Moreover, the as-prepared catalyst is easily recycled and can be reused at least five times without a significant loss of catalytic activity. Superior catalytic activity is mainly attributable to the unique structure of the catalyst, including synergetic electronic effect between Pd and Bi, as well as modulated surface character by acidification and N doping for better active components' anchoring and dispersion, as well as reactants' adsorption. This study provides a facial, practical, eco-friendly and efficient catalytic system for oxidative esterification of alcohols and shows promising prospect in industrial production.