Tracking the paths for the sucrose transformations over bifunctional Ru-POM/AC catalysts

• Published in: Catalysis today Vol. 357; pp. 113 - 121
• Main Authors: García-Bosch, N., Especel, Catherine, Guerrero Ruiz, A., Rodríguez-Ramos, I.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.11.2020; Elsevier
• Subjects: 1,2-propanediol; Activated carbon; Catalysis; Chemical Sciences; Fructose conversion; Polyoxometalates; Ruthenium; 1,2-propanediol; Polyoxometalates; Ruthenium; Activated carbon; Fructose conversion; 1.2-propanediol
• ISSN: 0920-5861; 1873-4308
• DOI: 10.1016/j.cattod.2019.05.052

[Display omitted] •Activated carbon support favors bifunctional active phases arrangement.•Metal and acidic functions are both needed for the sucrose evolution to propanediol.•Glucose is hydrogenated to sorbitol and subsequent reactions are halted.•Fructose transformation follows a direct route to produce propanediol.•Glycerol is not an intermediate compound of the PDO synthesis. The possible pathways of sugars transformation into 1,2-propanediol (PDO) have been studied, using new bifunctional catalysts for this catalytic multistep reaction. The catalysts are based on an acidic active phase (polyoxometalates, POMs) and a metallic function (Ru nanoparticles) supported over activated carbon (AC, SBET = 1190 m2/g). This support was loaded with 15 wt% of polyoxometalate, either phosphotungstic acid (TPA) or tungstosilicic acid (STA), while the amount of loaded ruthenium was close to 2 wt%. The catalytic materials were characterized by X-ray diffraction and electron microscopy techniques (SEM and TEM), while the surface active sites were evaluated using model reaction tests: cyclohexane dehydrogenation for metallic surface sites and isomerization of 3,3-dimethyl-1-butene for acid sites. For different sugars (sucrose, pentoses or hexoses) hydrogenation/hydrogenolysis using these catalysts in batch reactor was studied. The higher PDO selectivity was obtained in ethanol:water media and this study aims to establish the possible ways that sugars follow to achieve this transformation. The best catalytic material, 2%Ru-15%STA supported on AC, yields up to 50% of PDO selectivity when fructose is used as reactant, under moderate reaction conditions (413 K and 30 bar H2).