Study on activity and stability of Pt-Ru/WOx/Al2O3 catalyst in the glycerol selective hydrogenolysis to 1,3-propanediol

The deactivation of Pt/WOx/Al2O3 and Pt-Ru/WOx/Al2O3 catalysts in the glycerol hydrogenolysis to 1,3-propanediol (1,3-PDO) was investigated in autoclave. The selectivity of both catalysts toward 1,3-PDO was within 50–56% after the first five usages at 170 °C for 12 h with a H2 pressure of 9 MPa. With Pt/WOx/Al2O3, the conversion of glycerol decreased from 44.3% (1st reaction) to 27.2% (5th reaction), whereas a conversion of 52.4%, 48.0%, and 48.4% was obtained in the 1st, 5th, and 20th reactions, respectively, when Pt-Ru/WOx/Al2O3 was used. The characterizations of the catalysts showed that the pore structure of the catalyst changed because of the crystal structure of the catalyst support changing from γ-Al2O3 to pseudo-boehmite. However, the changes of the catalyst morphology were not responsible for the catalyst deactivation. Simultaneously, the acidity of catalysts was not shown to be a factor in their deactivation. On the other side, catalysts were not deactivated as a result of the loss of active components. Catalyst deactivation during glycerol hydrogenolysis was finally caused by the aggregation of active metal particles (Pt or Pt-Ru).