Reaction network and kinetics for the one-pot hydrogenolysis of cellulose to ethylene glycol over NiOx-WOy-Cu/MgAl2O4

Abstract

The reaction pathway and kinetics of cellulose hydrogenolysis to ethylene glycol (EG) catalyzed by nickel and tungsten combined with copper supported on magnesium aluminum spinel (NiOx-WOy-Cu/MgAl2O4) were studied. Cellulose was hydrolyzed to glucose, which followed either the retro-aldol condensation to glycolaldehyde and erythrose or isomerized to fructose followed by retro-aldol reaction to dihydroxyacetone and glyceraldehydes. The derived glucose can also be hydrogenated to sorbitol. The intermediate products were subsequently converted to EG, erythritol, glycerol and 1,2-propanediol. The cellulose conversion, yields of EG and C2,3 polyols were achieved 100, 53.1 and 62.7%, respectively. The simplified kinetic models were proposed and validated with the experimental results, indicating that the simpler first-order model could perfectly describe the hydrogenolysis of cellulose in the catalytic system. Hydrolysis of cellulose was demonstrated as the rate determining step independent of the reaction pathway, and high temperatures were favorable to the hydrolysis of cellulose to glucose. Activation energies results showed that high temperatures were favorable to the hydrolysis of cellulose to glucose.