Selective Hydrogenolysis of Glycerol with Raney Nickel

Glycerol, a cheap renewable feedstock, was converted selectively to 1,2-propanediol by heating under low hydrogen pressure (10 bar), in the presence of Raney nickel. No solvents or additives were required, and the product could be distilled out of the reaction mixture. Addition of a phosphonium salt, a liquid at the reaction temperature, improved the selectivity and rate to a small extent but did not facilitate the separation of the final reaction mixture.