Engineering acidic and Pt sites on WO3- doped H-mordenite supported Pt catalyst for hydrogenation of γ -valerolactone to methyl tetra hydrofuran

Abstract

The selective hydrogenation of gamma valerolactone (herein after GVL) into 2-methyl tetra hydrofuran (herein after MTHF) was studied over the different tungsten oxide-loaded Pt-doped H-Mordenite catalysts in a vapour phase continuous flow reactor. These catalysts were characterized by XRD, N2 adsorption-desorption analysis, SEM, TEM, FT-IR, Raman, XPS, TPR, NH3-TPD and pyridine adsorbed FT-IR analysis. XRD analysis result suggests that the tungsten oxide was well dispersed at low tungsten oxide loadings and, the tungsten oxide crystallites were formed at higher tungsten oxide loadings and the crystalline structure related to H-mordenite was retained for all the synthesised samples. The nitrogen adsorption-desorption analysis supported this result well. The TEM analysis confirms nano-sized platinum and tungsten oxide formation at 2Pt/10W-HM samples. The ammonia TPD analysis results suggested that all the samples possess weak and strong acidic sites and the amount and strength of acidic sites varies among the samples. The Pyridine adsorbed FT-IR results suggested that all the sample possesses mainly lewis acidic sites. These catalysts were evaluated for synthesising MTHF from GVL under different reaction conditions. Among the various synthesised catalysts studied, the 2 wt% Pt/10W-HM catalyst was identified as an effective catalyst with the 97 % conversion of GVL and the 98 % selectivity of MTHF. The higher catalytic performance depended on the distribution of surface tungsten oxide species along with the suitable acidic properties of the supported system.