Glycerol hydrogenolysis using a Ni/Ce‐Mg catalyst for improved ethanol and 1,2‐propanediol selectivities

Abstract

AbstractGlycerol, a byproduct from biodiesel production, is an inexpensive and renewable alternative feedstock for producing valuable chemicals. Hydrogenolysis of glycerol produces ethanol and 1,2‐propanediol (1,2‐PDO) with the help of appropriate catalysts. Commercially available non‐specific Ni‐based catalysts have been reported for use in producing ethanol along with 1,2‐PDO. In this work, a new Ni catalyst on various support materials was developed for the selective production of ethanol and 1,2‐PDO using glycerol hydrogenolysis. The Ni catalyst on CeO2 showed the highest potential for producing both ethanol and 1,2‐PDO. The catalyst with 0.15–0.50 g/g (15–50 wt%) Ni on CeO2 improved glycerol conversion at reaction temperatures of 215–245 °C, however 1,2‐PDO selectivity was unsatisfactory. An improvement in 1,2‐PDO selectivity was attained when Al, Si, Zn, and/or Mg were added as promoters to the Ni catalyst on CeO2, while improvement in the selectivity for ethanol occurred only with the addition of Si or Mg. A variation in Mg content showed that 1,2‐PDO selectivity was favoured at higher Mg content, while ethanol selectivity peaked at 10 % Mg. Systematic investigations found that the catalyst with 0.25 g/g (25 wt%) Ni on a Ce:Mg (4:1 mol:mol) support provided good selectivities for 1,2‐PDO at 68.10 % and ethanol at 9.0 %, respectively.