Pt/Al₂O₃ Catalyzed 1,3‐Propanediol Formation from Glycerol using Tungsten Additives

Abstract

Screening of four commercial catalysts (Pt/Al2O3, Pt/SiO2, Pd/Al2O3, and Pd/SiO2) and four acidic additives (hydrochloric, tungstic, phosphotungstic, and silicotungstic acids) shows that the combination of a platinum hydrogenation catalyst with tungsten containing acidic additives yields 1,3‐propanediol from aqueous glycerol. The performance of the best catalytic system Pt/Al2O3 with silicotungstic acid as an additive was optimized by experimental design, capturing the influence of reaction time, glycerol concentration, acid concentration, pressure, and temperature on the formation of 1,3‐propanediol from glycerol. High 1,3‐propanediol yield in an aqueous batch system can be achieved (49 % conversion, 28 % selectivity) with excellent 1,3‐propanediol to 1,2‐propanediol ratios. A mechanistic interpretation is given for this bifunctional system, supported by the relative stability of 1,3‐propanediol in comparison with 1,2‐propanediol under the chosen reaction conditions.

Effect of Tungsten Species on Selective Hydrogenolysis of Glycerol to 1,3‐Propanediol

“…Hanefeld and co-workers studied the effect of tungstic acid during Pt/Al 2 O 3 catalyzed the hydrogenolysis of glycerol. [51] It showed that the selectivity for 1,3-PDO was significantly improved by adding the H 2 WO 4 additive. It was possible that a glycerol tungstic acid ester was formed as an intermediate, which led to the selective formation of 1,3-PDO.…”

“…Hanefeld and co‐workers studied the effect of tungstic acid during Pt/Al 2 O 3 catalyzed the hydrogenolysis of glycerol [51] . It showed that the selectivity for 1,3‐PDO was significantly improved by adding the H 2 WO 4 additive.…”

“…Therefore, the tungsten‐based polyoxometalates can be used as homogeneous catalysts to interact with the reaction substrate in high possibility [15] . Hanefeld and co‐workers also investigated the effect of silicotungstic acid (H 4 SiW 12 O 40 ) and phosphotungstic acid (H 3 PW 12 O 40 ) in glycerol hydrogenolysis with Pt/Al 2 O 3 catalyst [51] . Experimental results indicated that the addition of H 4 SiW 12 O 40 (HSiW) and H 3 PW 12 O 40 to the reaction system significantly increased the conversion of glycerol and the selectivity for 1,3‐PDO.…”

“…Moreover, the yield of 1,3‐PDO is closely related to the amount of Brønsted acid sites in the hydrogenolysis of glycerol [74] . Various metals (Pt, Pd, Rh, Ru, Ir, Au, Ni, and Cu) were studied as the active sites in tungsten‐containing catalysts [51,62,76,88] . Among them, the Pt−W‐based catalysts were recognized as the best choice for the selective production of 1,3‐PDO, which benefited from the excellent hydrogen activation ability of Pt and synergistic effect between Pt and tungsten species.…”

Glycerol Hydrogenolysis to 1,3‐Propanediol on Tungstate/Zirconia‐Supported Platinum: Hydrogen Spillover Facilitated by Pt(1 1 1) Formation

“…reported that tungstic acid improved 1,3‐PDO selectivity on Rh‐based catalysts. ten Dam et al . screened four commercial catalysts and four acidic additives for glycerol hydrogenolysis and achieved 28 % 1,3‐PDO selectivity with 49 % conversion on Pt/Al 2 O 3 with silicotungstic acid as an additive.…”