Synthesis of metal oxides with strong basic sites from zirconium metal-organic frameworks and their catalytic performance in MPV reductions.

Meerwein-Ponndorf-Verley (MPV) reduction has gained much attention due to is mid reaction conditions, and this reaction can be performed without the presence of reductive atmosphere and the reaction conditions of high temperature and high pressure. Solid bases with abundant strong basic sites can be synthesized with metal-organic frameworks (MOFs) as precursors. These MOFs are immobilized with alkane metal nitrides, followed by calcination to produce the desired basic metal oxides. The basic zirconia shows highly efficient catalytic performance in MPV reduction of substrates with the carbonyl group, and benzaldehyde can be completely reduced in 6 hours with a mild reaction temperature (160 °C) in the absence of hydrogen gas. The catalytic efficiency is determined by the amounts of strong basic sites, but not the total amounts of basic sites, and this phenomenon is proved by the contrast experiments with the catalytic test of weak solid bases. Furthermore, the cooperative action between basic and acid sites can also enhance the catalytic performance in MPV reactions. With MOFs as precursors, metal oxide catalysts can be synthesized with well dispersed active sites. [ABSTRACT FROM AUTHOR]