Catalytic Conversion Of Cellulose Over Bi-functional Catalysts Of Ru-supported Heteropoly Compounds

Selective conversion of renewable lignocellulosic biomasses, such as cellulose, tolow molecular alcohols and/or hydrocarbons is crucial to a wide spread use of themost abundant, inexpensive and renewable resources. Producing commoditychemicals or fuels from biomass-based resources will reduce the dependent on fossilresources and help to improve a nation’s energy security.Heteropolyacids (HPAs) and salts of HPAs (M3/nPW12O40)，as green, efficient andpromising acid catalysts，have been investigated recently for cellulose hydrolysis andexhibited higher activity and selectivity for cellulose conversion than mineral acid. Aseries of Ru-supported solid acid bi-functional catalysts were prepared and thecatalytic activities for conversion of cellulose were studied.Bi-functional catalysts of active carbon and mesoporous carbon material CMK-3supported heteropolyacids and Ru were prepared and the catalytic activities forconversion of cellulose were studied. For the Ru/HPA-AC catalyst, a C2~C3polyolsselectivity of43.6%with a microcrystalline cellulose conversion of59.3%wasachieved. While, cellulose conversion was improved and C5~C6polyols was the mainproduct with a selectivity of71.7%catalyzed by the Ru/HPA-CMK-3catalysts.HPA leached to the liquid products was the main reason for the decreased catalyticactivities.Bi-functional catalysts of mesoporous SBA-15supported heteropolyacids and Ruwere prepared by one-pot synthesis method and the catalytic activities for conversionof cellulose were studied. A hexitols yield of36.8%with a microcrystalline celluloseconversion of59.3%was achieved in24h at463K and5MPa H2.A catalyst consisting of supported Ru and an ionic liquid (BmimPF6)–Heteropolyacid (H3PW12O40nH2O) hybrid as a support has been synthesized. Cellobiose as aprobe molecule was used to test the reactivity and selectivity of theRu/[Bmim]3PW12O40catalyst and the corresponding reaction mechanism wasproposed. The Ru/[Bmim]3PW12O40catalyst was further used in the conversion ofmicrocrystalline cellulose and further optimized the reaction conditions to maximizethe sorbitol yield. A sorbitol selectivity of70.3%with a microcrystalline celluloseconversion of63.7%was achieved in24h at433K and5MPa H2.