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Synthesis, isolation and characterization of methyl levulinate from cellulose catalyzed by extremely low concentration acid

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Journal of Energy Chemistry 2013年第6期22卷 895-901页

作者： Hui Li Lincai Peng Lu Lin Keli Chen Heng Zhang Faculty of Chemical Engineering Kunming University of Science and Technology State Key Laboratory of Pulp and Paper Engineering South China University of Technology School of Energy Research Xiamen University

A direct synthesis of methyl levulinate from cellulose alcoholysis in methanol medium under mild condition(180 210 C)catalyzed by extremely low concentration sulfuric acid(0.01 mol/L)and the product isolation were developed in this *** of different process variables towards the catalytic performance were performed as a function of reaction *** results indicated that sulfuric acid concentration,temperature and initial cellulose concentration had significant effects on the synthesis of methyl *** optimized yield of around 50%was achieved at 210 C for 120 min with sulfuric acid concentration of 0.01 mol/L and initial cellulose concentration below 100 g/*** resulting product mixture was isolated by a distillation technique that combines an atmospheric distillation with a vacuum distillation where n-dodecane was added to help distill the heavy *** light fraction including mainly methanol could be reused as the reaction medium without any substantial change in the yield of methyl *** chemical composition and structural of lower heavy fraction were characterized by GC/MS,FTIR,1H-NMR and13C-NMR *** levulinate was found to be a major ingredient of lower heavy fraction with the content over 96%.This pathway is efficient,environmentally benign and economical for the production of pure levulinate esters from cellulose.

关键词： cellulose methyl levulinate extremely low acid catalysis alcoholysis isolation

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Effective production of γ-valerolactone from biomass-derived methyl levulinate over CuO_x-CaCO_3 catalyst

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Chinese Journal of Catalysis 2019年第2期40卷 192-203页

作者： Xuejuan Cao Huai Liu Junnan Wei Xing Tang Xianhai Zeng Yong Sun Tingzhou Lei Geng Zhao Lu Lin Xiamen Key Laboratory of Clean and High-valued Utilization for Biomass College of EnergyXiamen UniversityXiamen 361102FujianChina Fujian Engineering and Research Center of Clean and High-valued Technologies for Biomass Xiamen 361005FujianChina Henan Key Lab of Biomass Energy Zhengzhou 450008HenanChina College of Chemistry and Chemical Engineering Xinyang Normal UniversityXinyang 464000HenanChina

The production of?-valerolactone(GVL)from lignocellulosic biomass has become a focus of research owing to its potential applications in fuels and *** this study,(n)CuOx-CaCO3(where n is the molar ratio of Cu to Ca)compounds were prepared for the first time and shown to function as efficient bifunctional catalysts for the conversion of biomass-derived methyl levulinate(ML)into GVL,using methanol as the in-situ hydrogen *** the catalysts with varied Cu/Ca molar ratios,(3/2)CuOx-CaCO3 provided the highest GVL yield of 95.6% from *** incorporation of CaCO3 with CuO resulted in the formation of Cu+species in a CuOx-CaCO3 catalyst,which greatly facilitated the hydrogenation of ***,CuOx-CaCO3 also displayed excellent catalytic performance in the methanolysis products of cellulose,even in the presence of ***,a facile two-step strategy for the production of GVL from cellulose could be developed over this robust and inexpensive catalyst,through the integration of cellulose methanolysis catalyzed by sulfuric acid,methanol reforming,and ML hydrogenation in methanol medium.

关键词： γ-Valerolactone methyl levulinate Hydrocyclization Methanol reforming Cellulose methanolysis

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Effects of Zr/Ti molar ratio in SO_4^(2-)/ZrO_(2-)TiO_2 calcined at different temperatures on its surface properties and glucose reactivity in near-critical methanol

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Journal of Natural Gas Chemistry 2012年第2期21卷 138-147页

作者： Lincai Peng Junping Zhuang Lu Lin State Key Laboratory of Pulp and Paper Engineering South China University of TechnologyGuangzhou 510640GuangdongChina School of Energy Research Xiamen UniversityXiamen 361005FujianChina

Effects of Zr/Ti molar ratio in SO42-/ZrO2-TiO2 solid acid catalyst calcined at different temperatures on its surface properties and catalytic activity were thoroughly investigated in this paper. The physicochemical characteristics of prepared samples were determined by N2 adsorptiondesorption, XRD, NH3-TPD and XPS techniques, respectively. It was found that the crystallization temperature of the samples increased after the combination of ZrO2 and TiO2; and phase transformations from the anatase to the rutile of TiO2 species and the tetragonal to the monoclinic of ZrO2 species were effectively suppressed at higher temperature. The sample with a Zr/Ti molar ratio of 3/1 calcined at 450℃ showed the highest surface area and the most acid sites among all the tested samples. The acid site densities of samples were relatively closed to each other if they were calcined at the same temperature, however, decreased with the calcination temperature. The result indicates that the sulfur content in samples is a crucial factor to control the acid site density. Calcining the sample at 650℃ and higher temperatures resulted in a significant desorption of sulfate ion on the samples. The synthesized samples were evaluated as a potential catalyst for glucose conversion under the near-critical methanol conditions （200℃/4 MPa）. The results suggested that the relatively weaker acid sites of the catalyst were more favorable for the accumulation of methyl glucosides, while the moderate acid sites were responsible for the formation of methyl levulinate. The catalytic activity for methyl levulinate production almost increases linearly with the catalyst acid site density. The catalyst deactivation is due to the loss of sulfate ion and the two catalysts with Zr/Ti molar ratios of 3/1 and 1/3 could effectively alleviate the deactivation caused by sulfate solution in the reaction medium and can be reused after calcination with the reuse rate of over 90% in terms of the methyl levulinate selectivi

关键词： SO42-/ZrO2-TiO2 surface properties catalysis glucose reactivity methyl levulinate

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