Hydrogenolysis of Glycidol as an Alternative Route to Obtain 1,3-Propanediol Selectively Using MOx-Modified Nickel-Copper Catalysts Supported on Acid Mesoporous Saponite

摘要

Ni and Cu mono- and bimetallic catalysts modified with various types of acid oxides MOx (M=Mo, V, W, and Re) were tested for the hydrogenolysis of glycidol as an alternative route to the hydrogenolysis of glycerol to obtain 1,3-propanediol (1,3-PrD). Characterization results revealed that the presence of modifiers affected the dispersion and reducibility of the NiO particles and the strength and amount of acid sites. Among the modifiers tested, Re led to the highest activity, a high propanediols selectivity, and the highest 1,3-PrD/1,2-propanediol (1,2-PrD) ratio. The Ni-Cu/Re ratio was optimized to improve the catalytic activity. The best catalytic result, with a 46% 1,3-PrD yield and a 1,3-PrD/1,2-PrD ratio of 1.24, was obtained if the monometallic Ni catalyst at 40wt% loading and modified with 7wt% Re was used at 393K and 5MPa H-2 pressure after 4h of reaction. The overall 1,3-PrD yield starting from glycerol and assuming a two-step synthesis (glycerolglycidol1,3-PrD) and a yield of 78% for the first step would be 36%. This 1,3-PD yield is the highest for a reaction catalyzed by a non-noble metal and is comparable to the direct hydrogenolysis of glycerol using noble metal catalysts at a longer time and a high H-2 pressure.