Development of catalysts for possible hydrogenation of xylose to xylitol.

Abstract

This project aimed to synthesize and characterize a novel catalyst for the transfer hydrogenation of xylose to xylitol. A literature review revealed that palladium supported on an aluminium-tin mixed metal oxide support was the best catalyst to facilitate the reaction due to palladiums electron configuration, superior hydrogen bonding capacity, strong metal-support interactions and amphoteric nature of the support material. Catalysts of nominal palladium loading 5 wt.% supported on tin-alumina mixed metal oxides of molar composition 10 %, 20 % ,30 %, 40 % and 50 % Sn were successfully synthesised using the microwave assisted sol-gel method and characterised using BET, EDX, SEM and XRD techniques. Catalyst surface area decreased with tin composition from 200 m2/g at 10% Sn to 60 m2/g at 50% tin. SEM imaging confirmed nanoparticle formation with varying morphology depending on tin composition. EDX confirmed even dispersion of 5 wt. % Pd with one anomaly after impregnation and calcination. EDX maps indicate high density of Sn as it is more dense than Al. XRD confirmed the crystalline structure with the formation of both alpha and gamma-alumina phases. A sustainability analysis indicated that the biological process is more environmentally friendly than the chemical route. Future work would entail testing the catalysts for their intended application.