Effect of Ru Precursors and Reduction Conditions on Catalyst Performance in Glycerol Hydrogenolysis

Catalyst precursors, their reduction protocols and reaction conditions integrally influenced the activity and selectivity pattern in glycerol hydrogenolysis. Ru prepared from chloride precursor (Ru(Cl)/C−B) showed the maximum selectivity to C−C cleavage products EG (56 %) and methanol (17 %) with 23 % selectivity to 1,2‐PDO. While, that prepared from nitrosyl precursor (Ru(n)/C−B) showed higher selectivity to 1,2‐PDO (44 %) and lower to EG (42 %). The catalysts prepared either with chloride or nitrosyl precursors but reduced by H2 showed lower glycerol conversion (10‐11 %) than NaBH4 reduced catalysts. For these catalysts, 1,2‐PDO selectivity increased to 40–43 % along with the major formation of 2‐propanol (48‐49 %) and very less selectivities to C−C cleavage products. The lower activity of the H2 reduced catalysts can be related to their lower acidity and the bigger Ru metal particle size (3‐5 nm). For Ru(Cl)/C−B catalyst, glycerol conversion increased from 28–97 % with a rise in temperature from 180 to 250 oC also favoring 1,2‐PDO selectivity; indicating that C−O bond cleavage was favoured in comparison to C−C scission, at higher temperature. History shapes the future: Activity and product selectivities in glycerol hydrogenolysis could be altered by varying Ru precursors, reducing agents and reaction conditions. Three times higher selectivity to EG than 1,2‐PDO was obtained using chloride precursor and prereduction by NaBH4 as compared to Ru‐nitrosyl precursor While, H2 prereduced Ru catalysts gave only C3 diol.