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  • Wiley  (4)
  • Liu, Qing  (4)
  • Sun, Kai  (4)
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  • Wiley  (4)
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  • 1
    Online Resource
    Online Resource
    Sulfated Zirconia with Different Crystal Phases for the Production of Ethyl Levulinate and 5‐Hydroxymethylfurfural
    Wiley ; 2020
    In:  Energy Technology Vol. 8, No. 3 ( 2020-03)
    Details
    In: Energy Technology, Wiley, Vol. 8, No. 3 ( 2020-03)
    Abstract: Distinct crystal phases of an oxide affect the configuration of surface atoms, which might further affect coordination with sulfate during sulfonation for the preparation of SO 4 2− /M x O y type of acid catalyst. Herein, such an effect is investigated with zirconia of the tetragonal or monoclinic phase as the model catalysts. The results show that sulfonation inhibits the transformation of zirconia from the tetragonal phase to the monoclinic phase, whereas the varied phase of zirconia also affects the bonding patterns of sulfate species with zirconia in sulfonation. The sulfated zirconia of monoclinic phase contains more abundant acidic sites and more Brønsted acid sites than that of sulfated zirconia of tetragonal phase. Consequently, the sulfated zirconia of monoclinic phase is more active than the sulfated zirconia of tetragonal phase for the conversion of furfuryl alcohol in ethanol and conversion of fructose in dimethyl sulfoxide, achieving the yield of ethyl levulinate of 96.4% and a high yield of 5‐hydroxymethylfurfural. The sulfated zirconia is not stable in protic solvent due to the leaching of sulfur species and the change in configurations of the sulfate species and the zirconium species, but in the aprotic solvent, they show good stability and recyclability.
    Type of Medium: Online Resource
    ISSN: 2194-4288 , 2194-4296
    URL: Issue
    URL: Article
    DOI: 10.1002/ente.v8.3
    DOI: 10.1002/ente.201900951
    Language: English
    Publisher: Wiley
    Publication Date: 2020
    detail.hit.zdb_id: 2700412-0
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  • 2
    Online Resource
    Online Resource
    Conversion of monosaccharides into levulinic acid/esters: impacts of metal sulfate addition and the reaction medium
    Wiley ; 2019
    In:  Journal of Chemical Technology & Biotechnology Vol. 94, No. 11 ( 2019-11), p. 3676-3686
    Details
    In: Journal of Chemical Technology & Biotechnology, Wiley, Vol. 94, No. 11 ( 2019-11), p. 3676-3686
    Abstract: Inorganic salts could be used as catalysts for the effective conversion of sugars. In this study, the impacts of various metal sulfates (Na 2 SO 4 , K 2 SO 4 , MnSO 4 , CoSO 4 , NiSO 4 , ZnSO 4 , CuSO 4 , Fe 2 (SO 4 ) 3 , La 2 (SO 4 ) 3 and Ce(SO 4 ) 2 ) on the conversion of glucose/fructose to levulinic acid in varied reaction media were evaluated. RESULTS The sulfates strongly chelated with the sugars, preventing their dehydration reactions in the presence of sulfuric acid and leading to polymerization of the sugars. The sulfates themselves showed varied activity and selectivity for the conversion of the sugars to levulinic acid/esters or 5‐hydroxymethylfurfural (HMF), depending on the coordination with the reaction medium. K 2 SO 4 or Na 2 SO 4 could catalyze the production of HMF from glucose/fructose in water, while in DMSO the yield of HMF was substantially higher. In THF, nevertheless, almost no HMF was formed, while other sulfates such as NiSO 4 in THF could effectively catalyze the conversion of fructose to HMF. In alcohols, Fe 2 (SO 4 ) 3 was the most effective sulfate for the conversion of the sugars to levulinic acid/esters, and the alcohols could effectively suppress the polymerization of the sugars. CONCLUSION The distinct catalytic performances of the sulfates in the varied reaction media originated from their different coordination or chelation with the sugars and the reaction medium. © 2019 Society of Chemical Industry
    Type of Medium: Online Resource
    ISSN: 0268-2575 , 1097-4660
    URL: Issue
    URL: Article
    DOI: 10.1002/jctb.v94.11
    DOI: 10.1002/jctb.6172
    Language: English
    Publisher: Wiley
    Publication Date: 2019
    detail.hit.zdb_id: 1479465-2
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  • 3
    Online Resource
    Online Resource
    Investigation into Properties of Carbohydrate Polymers Formed from Acid‐Catalyzed Conversion of Sugar Monomers/Oligomers over Brønsted Acid Catalysts
    Wiley ; 2020
    In:  Energy Technology Vol. 8, No. 6 ( 2020-06)
    Details
    In: Energy Technology, Wiley, Vol. 8, No. 6 ( 2020-06)
    Abstract: Steric hindrance is an intrinsic issue for solid acid catalysts in catalyzing conversion of sugars with a certain size. Herein, the conversion of furfural and sugar monomers/oligomers over a heterogeneous catalyst (D008) and homogeneous acid (H 2 SO 4 ) is conducted in aqueous medium. The results indicate the steric hindrance of D008 shows more significant effects on the conversion of the sugars than that of furfural, as the chain form of the sugar monomers/oligomers is much bigger than that of furfural in size. The high local concentration of hydrogen ions on D008 facilitates furfural polymerization via opening of the furan ring through hydration reactions. The deactivation of D008 is responsible for the low yield of volatile products when the polymer formed from the polymerization of the sugars fills the pores. The sugar structures determine the polymer's properties. Thermal stability of the coke derived from the sugar oligomers is lower than that from the sugar monomers due to more aliphatic structures in the resulting coke. In addition, the coke derived from the sugars is more hydrophilic than that from furfural, due to the multiple hydroxyl group in the sugar substrates.
    Type of Medium: Online Resource
    ISSN: 2194-4288 , 2194-4296
    URL: Issue
    URL: Article
    DOI: 10.1002/ente.v8.6
    DOI: 10.1002/ente.201901476
    Language: English
    Publisher: Wiley
    Publication Date: 2020
    detail.hit.zdb_id: 2700412-0
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  • 4
    Online Resource
    Online Resource
    Sulfated TiO 2 nanosheets catalyzing conversion of biomass derivatives: influences of the sulfation on distribution of Brønsted and Lewis acidic sites
    Wiley ; 2020
    In:  Journal of Chemical Technology & Biotechnology Vol. 95, No. 5 ( 2020-05), p. 1337-1347
    Details
    In: Journal of Chemical Technology & Biotechnology, Wiley, Vol. 95, No. 5 ( 2020-05), p. 1337-1347
    Abstract: The synthesis of solid acid catalysts of recoverable and environmentally friendly nature has gained increasing attention in recent years. The distribution of Brønsted and Lewis acidic sites on the surface of sulfated metal oxides determines the catalytic performance, which is affected by many key factors, such as the concentration of sulfuric acid impregnated and the morphology of the metal oxides used. In this study, TiO 2 nanosheets were successfully synthesized and used as carrier for the preparation of solid acid catalysts. RESULTS The concentration of sulfuric acid for the impregnation resulted in various distributions of Brønsted and Lewis acidic sites on the surface of sulfated TiO 2 . With a medium concentration of sulfuric acid (1 mol L −1 ) for the impregnation, the highest ratio of Brønsted to Lewis acidic sites can be achieved, and the catalyst showed superior catalytic activity for the conversion of furfuryl alcohol (FA) to ethyl levulinate (EL) in ethanol and the conversion of fructose to 5‐hydroxymethylfurfural (HMF) in dimethyl sulfoxide (DMSO). CONCLUSION The sulfation of TiO 2 nanosheets induced the formation of both Brønsted and Lewis acidic sites. The Brønsted acidic sites were more effective for catalyzing the conversion of FA or fructose. The poor recyclability of the 1.0‐SO 4 2− /TiO 2 catalyst in the conversion of FA to EL in ethanol, a protic solvent, was due to the leaching of sulfur species. The deactivation of the catalyst in DMSO was due to coking, which could be resolved via calcination of the coke species in air. © 2019 Society of Chemical Industry
    Type of Medium: Online Resource
    ISSN: 0268-2575 , 1097-4660
    URL: Issue
    URL: Article
    DOI: 10.1002/jctb.v95.5
    DOI: 10.1002/jctb.6318
    Language: English
    Publisher: Wiley
    Publication Date: 2020
    detail.hit.zdb_id: 1479465-2
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