Selective production of acetol or methyl lactate from cellulose over RuSn catalysts

摘要

Designing a catalytic system that could convert cellulose to switchable C3 alcohols or esters with controllable selectivity is highly desired to meet the rapidly changing market demand. Herein, we develop RuSn catalysts with the altering Sn loadings that can achieve acetol formation from cellulose hydrogenation at 240 degrees C in presence of H-2 or yield methyl lactate production from cellulose conversion in methanol and water mixture at 200 degrees C in presence of N-2. The increased Sn contents from 3% to 6% lead to form different surface sites from Ru3Sn7, Ru, and SnOx to Ru3Sn7 and SnOx. The integrated Ru3Sn7, Ru, and SnOx species on 1.5%Ru-3%Sn/SiO2 catalyze isomerization, retro-aldol condensation, and hydrogenation individual steps with coordinated reaction rates, resulting in the acetol formation with a high yield of 53.7C%. Furthermore, the optimum combination of Ru3Sn7 and SnOx on 1.5%Ru-6%Sn/SiO2 contributes to the isomerization, retro-aldol condensation, dehydration, and 1,2-hydride shift, giving rise to the preferential production of methyl lactate at a 25.1C% yield. These results illustrate the feasibility of controlling the selective conversion of cellulose to C3 acetol or methyl lactate by devising a tunable catalytic system, which guides the rational design of catalysts for the selective conversion of cellulose.

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