Hydrogenolysis of glycerol to 1,2-propanediol catalyzed by Cu-H_4SiW_(12)O_(40)/Al_2O_3 in liquid phase

摘要

BACKGROUND: Crude glycerol will increase to over 400 million L year~(?1), and the market is likely to become saturated due to the limited demand for glycerol. The main aim of this work is to develop a novel process for the sustainable conversion of glycerol to 1,2-propanediol (l,2-PD). RESULTS: Cu-H_4SiW_(12)O_(40)/Al_2O_3 catalysts with different H_4SiW_(12)O_(40) (STA) loadings were prepared for the hydrogenolysis of glycerol to produce l,2-PD in liquid phase. At 513 K, 6 MPa and LHSV of 0.9 h~(?1) in 10% (w/w) glycerol aqueous solutions, the catalyst with 5% (w/w) STA showed the best performance with 90.1% of glycerol conversion and 89.7% selectivity to l,2-PD. More important, both the initial glycerol conversion and l,2-PD selectivity were maintained over 250 h. CONCLUSION: l,2-PD can be continuously produced with high yields via the liquid phase hydrogenolysis of glycerol over Cu-H_4SiW_(12)O_(40)/Al_2O_3. Furthermore, the characterization indicated that catalyst acidity could be greatly modified by STA, which promoted Cu reducibility. It was also found that hydrogenolysis could be favored by a bi-functional catalyst with the appropriate amount of both acid and metal sites.