Hydrogenolysis of disaccharides into propylene glycol on copper-containing oxides

Abstract

The hydrogenolysis of 10 % methanol-water solutions of sucrose and maltose to propylene glycol on supported copper-containing catalysts in flow reactor was studied. The highest concentration of propylene glycol in the reaction products (0.23 mmol/ml) has been obtained in the hydrogenolysis of sucrose on  23Cu-1Cr₂O₃/Al₂O₃ catalyst with its full conversion at 170 °C/4.0 MPa H₂ and a load on catalyst of 0.8 mmol С₁₂Н₂₂О₁₁/g_cat/h. At that, the catalyst productivity towards propylene glycol consists 0.7 mmol/g_cat/h. Hydrogenolysis of maltose in these conditions is characterized by 81 % conversion and low (0.04 mmol/ml) concentration of propylene glycol in the reaction products. The main byproducts of sucrose hydrogenolysis are ethylene glycol, hydroxyacetone, 1,2-butanediol, 1,4-butanediol and sorbitol. Concentration of propylene glycol in the reaction products of sucrose hydrogenolysis on 23Cu-1Cr₂O₃/Al₂O₃ does not change significantly  (0.23-0.18 mmol/ml) during 18 h of catalyst operation. Сomparison of the productivities of 23Cu-1Cr₂O₃/Al₂O₃ catalyst to propylene glycol in hydrogenolysis of 10 % solutions of sucrose (0.7 mmol/g_cat/h) and glucose (0.9 mmol/g_cat/h) suggests that glucose is more suitable for the production of propylene glycol than studied disaccharides.