SnO2 modified intermetallic PdSn for selective hydrogenation of phenol to cyclohexanone with hydrogen donor

Lignin oil consists of a large amount of phenolic compounds, and how to economically and efficiently utilize its phenolic compounds remains challenging while chitin is the second largest natural organic compounds in quantity, and finding its more application is highly desired. In this work, we demonstrate to use chitin as supports to prepare SnO2 modified intermetallic PdSn bifunctional catalysts for hydrogenation of phenolic compounds to cyclohexanone derivatives. Under mild reaction conditions and HCOONa as hydrogen donor, the synthesized Pd1Sn2Ox/chitin exhibits 99.3 % of phenol conversion and 99.8 % of cyclohexanone selectivity, and illustrates a wide adaptability for selective hydrogenations of various methylphenols and dihydroxybenzenes. Theoretic calculations and experimental results suggest that the significant enhancement can be attributed to the synergistic effect between SnO2 and the formation of PdSn intermetallic phase, where the Lewis acid SnO2 promotes the activation of the benzene rings of phenolic compounds and intermetallic PdSn accelerates HCOONa in water medium to release H2 for hydrogenation.