Investigation of the bifunctionality of catalysts based on Rh associated with an oxophilic promoter in the hydrogenolysis of tetrahydrofurfuryl alcohol to 1,5-pentanediol

The hydrogenolysis of tetrahydrofurfuryl alcohol was studied in aqueous phase over a range of bifunctional catalysts based on Rh and an oxophilic promoter (Re, W, Mo) supported on ZrO2. The structures of the catalysts were characterised employing powder XRD, Raman spectroscopy and TEM analysis. The degrees of reduction were evaluated by H2-TPR and XPS analyses. The metallic properties were assessed by CO chemisorption. For the first time, the acidic properties were evaluated in aqueous phase by calorimetric measurements of 2-phenyl-ethylamine adsorption heat. The combination of metallic Rh sites and Bronsted sites (linked to the oxophilic metal on ZrO2) is crucial for the reaction. The bifunctionality of the catalysts was demonstrated and up to 81% yield of 1,5-pentanediol is obtained with 5%Rh-4%Mo/ZrO2.