title: Conversion of cellulose and cellobiose into sorbitol catalyzed by ruthenium supported on a polyoxometalate/metal-organic framework hybrid.
abstract: Cellulose and cellobiose were selectively converted into sorbitol over water-tolerant phosphotungstic acid (PTA)/metal- organic-framework-hybrid-supported ruthenium catalysts, Ru-PTA/MIL-100(Cr), under aqueous hydrogenation conditions. The goal was to investigate the relationship between the acid/metal balance of bifunctional catalysts Ru-PTA/MIL-100(Cr) and their performance in the catalytic conversion of cellulose and cellobiose into sugar alcohols. The control of the amount and strength of acid sites in the supported PTA/MIL-100(Cr) was achieved through the effective control of encapsulated-PTA loading in MIL-100(Cr). This design and preparation method led to an appropriately balanced Ru-PTA/MIL-100(Cr) in terms of Ru dispersion and hydrogenation capacity on the one hand, and acid site density of PTA/MIL-100(Cr) (responsible for acid-catalyzed hydrolysis) on the other hand. The ratio of acid site density to the number of Ru surface atoms (nA /nRu ) of Ru-PTA/MIL-100(Cr) was used to monitor the balance between hydrogenation and hydrolysis functions; the optimum balance between the two catalytic functions, that is, 8.84<nA /nRu <12.90, achieves maximum conversion of cellulose and cellobiose into hexitols. Under the applied reaction conditions, optimal results (63.2% yield in hexitols with a selectivity for sorbitol of 57.9% at complete conversion of cellulose, and 97.1% yield in hexitols with a selectivity for sorbitol of 95.1% at complete conversion of cellobiose) were obtained using a Ru-PTA/MIL-100(Cr) catalyst with loadings of 3.2 wt % for Ru and 16.7 wt % for PTA. This research thus opens new perspectives for the rational design of acid/metal bifunctional catalysts for biomass conversion.
authors.affiliation: Key Laboratory of Renewable Energy and Natural Gas Hydrate, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640, PR China. chenjz@ms.giec.ac.cn
authors.forename: Jinzhu
authors.initials: J
authors.lastname: Chen
authors.forename: Shengpei
authors.initials: S
authors.lastname: Wang
authors.forename: Jing
authors.initials: J
authors.lastname: Huang
authors.forename: Limin
authors.initials: L
authors.lastname: Chen
authors.forename: Longlong
authors.initials: L
authors.lastname: Ma
authors.forename: Xing
authors.initials: X
authors.lastname: Huang
mesh_terms: D002384:Catalysis; D002475:Cellobiose / Q000737:chemistry*; D002482:Cellulose / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry; D008958:Models, Molecular; D008968:Molecular Conformation; D009942:Organometallic Compounds / Q000737:chemistry*; D012428:Ruthenium / Q000737:chemistry*; D013012:Sorbitol / Q000737:chemistry*
chemical_list: D009942:Organometallic Compounds; D002475:Cellobiose; D013012:Sorbitol; D012428:Ruthenium; D002482:Cellulose
keywords: acidity; green chemistry; heterogeneous catalysis; metal-organic frameworks; polyoxometalates