High-Performance Ni₃P/meso-SiO₂ for Gas-Phase Hydrogenation of Dimethyl Oxalate to Methyl Glycolate

Abstract

Three meso-SiO2 (RB-MSN, HMS, and MCM-41) supported Ni3P catalysts to be used in gas-phase hydrogenation of dimethyl oxalate (DMO) to methyl glycolate (MG) are prepared via the impregnation method and subsequent H2-reduction treatment. The as-obtained catalysts show interesting meso-SiO2-type-dependent reactivity for this reaction, which is tightly linked with the support Si–OH amount rather than the support textural/structural properties and Ni3P grain size. The Ni3P/RB-MSN outperforms the two others, being capable of fully converting DMO with 85.0% MG selectivity and being stable for at least 500 h under mild conditions. The turnover frequency and Ea of such a catalyst for this reaction are calculated to be 204.2 h–1 and 84.0 kJ mol–1. Lack of Si–OH in RB-MSN diminishes the interaction of NiO and POx with Si–OH groups, thereby not only enabling NiO and POx to be easily and fully reduced to form Ni3P but also suppressing the formation of harmful irreducible POx species.