Reactivity and mechanism investigation of selective hydrogenation of 2,3,5-trimethylbenzoquinone on in situ generated metallic cobalt

Abstract

Efficient and inexpensive catalysts are urgently desired for the hydrogenation of 2,3,5-trimethylbenzoquinone (TMBQ) to 2,3,5-trimethylhydroquinone (TMHQ), a key vitamin-E intermediate. In this study, a one-step method was developed to synthesize uniform cobalt-based NPs supported on porous nitrogen-doped carbon for the hydrogenation of TMBQ to TMHQ. The as-prepared catalyst shows a high yield (>90%) and selectivity (>99%) for TMBQ hydrogenation as well as α,β-unsaturated carbonyls. The satisfactory performance is attributed to the small particle size and homogeneous distribution. Meanwhile, metallic Co is proved to be responsible for the catalytic activity. Furthermore, density functional theory calculation discloses that the excellent chemoselectivity towards TMBQ is due to the preference for a desorption process over sequential hydrogenation of TMHQ. This novel material has great potential as a non-precious-metal catalyst for heterogeneous hydrogenation processes, due to its outstanding catalytic performance, simple preparation method and low production cost.