One-pot selective conversion of cellulose into low carbon polyols on nano-Sn based catalysts

Abstract

The direct hydrogenolysis of cellulose on bimetallic catalysts represented a promising route for polyols' production. The development of a catalyst system that could control the promotion of the selectivity of polyols for the conversion cellulose into polyols was highly desirable. In this work, we realized the production of ethylene glycol (EG) and 1,2-propylene glycol (1,2-PG) by adopting nano-Sn species with different valences in combination with Ni catalysts, and the catalysts were prepared by the incipient-wetness impregnation method. The catalyst 10%Ni–15%Sn/SBA-15 achieved the highest yield of C2-C3 polyols, yielding up to 67.2% with a higher selectivity to 1,2-PG. The Ni and Sn species and some NiSn alloys were found to be the active sites for the EG and PG as evidenced by control experiments and characterization including X-ray diffraction, X-ray photoelectron spectroscopy, and transmission electron microscopy. The catalytic particles were located on the outer surface of SBA-15 (pore size = 6–10 nm) on a nanoscale with sizes of 11.1 ± 1.9 nm. The effects of the supports and hydrogenating species were investigated for cellulose conversion. The experimental results disclosed that the Sn species with different valences possessed obvious functions for the retro-aldol condensation, and the Ni components boomed the hydrogenation process. The other detailed analyses on the formation of polyols were described. As a consequence, controlling the EG and PG product distribution could be realized using Sn based catalysts.