Hydrogenolysis of Aqueous Glycerol over Raney Nickel Catalyst: Comparison of Pure and Biodiesel By-Product

Abstract

The hydrogenolysis of pure and biodiesel byproduct glycerol in the presence of Raney nickel catalyst using an autoclave was studied. The effects of stirring speed, temperature, amount of catalyst, H2 pressure, and glycerol content on the conversion of glycerol, the yield of liquid products, and the selectivity of 1,2-propanediol were investigated, and the results were compared to chemically pure glycerol and crude glycerol from biodiesel production. All the experimental results obtained from the use of crude glycerol from biodiesel production were close to those obtained from the use of chemically pure glycerol. The highest conversion of glycerol (80%) was achieved under the conditions of 35 g catalyst L–1 solution, 20% glycerol content, 40 bar H2 pressure, 400 rpm stirring speed, and 230 °C temperature for the chemically pure glycerol. In order to reach the highest liquid products yield (95%) and the 1,2-propanediol selectivity (54%), the catalyst amount was decreased from 35 g catalyst L–1 solution to 7...