ACS Sustainable Chemistry & Engineering
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2014
·
IF 0
Jinxu Xi,Daqian Ding,Yi Shao,Xiaohui Liu,Guanzhong Lu,Yanqin Wang
The efficient usage of lignocellulosic biomass is of great significance for large-scale low-cost biomass conversion to biofuels and other useful chemicals. Here, an interesting catalytic process was reported related to converting cellulose into ethylene glycol (EG) and ethylene glycol monoether (EGME) in methanol over a Ru/NbOPO4 catalyst, with the cleavage of a C–C bond by NbOPO4 and further hydrogenation by supported Ru particles. The influence of reaction temperature, hydrogen pressure, and reaction time was systematically investigated and showed that a 54.5% total yield of EG and EGME could be obtained at 220 °C in 3 M Pa H2, which was an exciting result. Meanwhile, the effect of solvent was also studied in detail. It was shown that methanol played an important role in the production of EG and EGME, especially in the cleavage of the C–C bond. Methanol could protect the C═O bond in glucose produced from cellulose through acetalization, thus prevent its hydrogenation, and led to the production of EG and EGME. Furthermore, the influence of dopants (W, Sn, Ni, Cu) was further investigated, and it was found that only the Ru–Ni/NbOPO4 catalyst was more effective through limiting the further hydrogenolysis of products (EG and EGME) to CO and alkanes, and as high as 64% total yield of EG+EGME was achieved. Moreover, the Ru–Ni/NbOPO4 catalyst showed good reusability, which can be reused at least four times with a little loss in EG and EGME yield.
研究领域:
化学工程
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生物质能转化
✓ 已验证
产品关联
DOI
APPLIED CATALYSIS B-ENVIRONMENTAL
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2015
·
IF 7.435
Jinxu Xi,Qineng Xia,Yi Shao,Daqian Ding,Panpan Yang,Xiaohui Liu,Guanzhong Lu,Yanqin Wang
Liquid bio-fuels derived from renewable biomass are of great importance on the potential substitution for the diminishing fossil fuels. Aqueous-phase process of sugar and sugar-derived molecules can be used to produce a range of alkanes and oxygenates. In this work, Pt/NbOPO 4 multifunctional catalyst was used in the alkane production by the hydrodeoxygenation of sorbitol in aqueous solution. The results indicated that Pt/NbOPO 4 catalyst showed the highest activity with 60% yield of C6 and C5 alkanes at 250 °C and 4 MPa H 2 among a series of catalysts. The reaction pathway showed that this process included dehydration, hydrogenolysis and CC bond cleavage. Isosorbide is the product of dehydration reaction and also an important intermediate in this process, which undergoes ring opening and following hydrogenolysis to form C6 hexane. The activation energy of sorbitol dehydration and isosorbide hydrogenolysis was calculated, that is 72.7 kJ/mol and 147.6 kJ/mol, respectively, over Pt/NbOPO 4 catalyst, much lower than those over Pt/ZrP and Pt/H-Beta catalysts, which would be attributed to the strong and high acid amount of NbOPO 4 as well as the promotion effect of NbO x for CO bond cleavage. The above results also showed that isosorbide hydrogenolysis is the rate-determine step. More importantly, Pt/NbOPO 4 catalyst was very stable, there was nearly no decrease of sorbitol conversion and no change of products distribution after working in a fixed bed reactor for 100 h. Therefore, Pt/NbOPO 4 is an efficient and stable catalyst for hexane production from sorbitol in aqueous media.
研究领域:
能源科学
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催化化学
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2022
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IF 4.326
Lei Wang,Xiaohui Liu,Yanqin Wang,Weizhen Sun,Ling Zhao
Isosorbide is a bio-based platform compound, and the solid acid-catalyzed conversion of sorbitol to isosorbide is an environment-friendly process. The thermodynamic calculations and reaction kinetics of the sorbitol dehydration to isosorbide catalyzed by NbOPO4 were studied in this work. The thermodynamic analysis shows that the two-step dehydration of sorbitol is an endothermic process, in which the first one is an irreversible reaction while the second is a reversible one. Based on the reaction mechanism and thermodynamics, a first-order pseudo-homogeneous kinetic model for the sorbitol dehydration was proposed. The modeling fitting results show that the kinetic model established in this work can well fit the experiments in the range of 493.15–523.15 K. The kinetic investigation and thermodynamic analysis indicate that low temperatures would decrease the generation of byproducts in the first step while high temperatures promote the reaction equilibrium forward in the second step. Therefore, a two-stage temperature gradient way with high temperatures followed by low temperatures would be favorable in the conversion of sorbitol to isosorbide catalyzed by NbOPO4. Hopefully, the thermodynamics and kinetic modeling results obtained in this work would guide the design of solid acid catalysts and reactors for the sorbitol dehydration process.
研究领域:
化学工程
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催化科学
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生物基材料
✓ 已验证
DOI
高影响因子
FUEL
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2023
·
IF 7.4
Danni Liu,Xiaopo Niu,Zhen Guo,Kaige Zhang,Nan Jiang,Yue Qin,Wenli Zhao,Xiangwen Zhang,Qingfa Wang
Upgrading lignocellulose biomass to renewable fuels is essential to achieve carbon neutrality. However, the multiple synthetic, and purification steps as well as the employment of solvents in the production of renewable fuel inhibit the overall yields and cause the waste of energy and resources. Herein, a new catalytic strategy for one-pot solvent-free sequential synthesis (OSS) of perhydrofluorene and dicyclohexylmethane was developed from lignin-derivatives. A two-dimensional layered nanosheet niobium phosphate (NbOPO 4 -IB) catalyst was fabricated to efficiently integrate the alkylation of phenol and benzyl alcohol and sequential hydrodeoxygenation with a cocatalyst of Ru/C. The high crystalline NbOPO 4 phase and the lamellar morphology contributes to the large specific surface area to expose more active sites, especially more Brønsted acid sites. The NbOPO 4 -IB catalyst with a suitable Brønsted/Lewis acid ratio of 1.49 favors the selectivity of fuel precursors benzyl phenol in the alkylation and also provides the appropriate acid strength to promote hydrodeoxygenation activity. NbOPO 4 -IB also shows good reusability. Excessive phenol plays a vital role in promoting the alkylation reaction by dissolving the intermediates, and then into cyclohexane to enhance the H 2 dissolution in the hydrodeoxygenation. A possible mechanism of OSS from lignin-derivatives into polycycloalkanes over the cocatalysts was proposed.
研究领域:
催化化学
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可再生能源
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
Catalysis Science & Technology
·
2018
·Vol. 8
·期 3
·735-745
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IF 5.365
Lin Dong,Li-Li Yin,Qineng Xia,Xiaohui Liu,Xue-Qing Gong,Yanqin Wang
One-pot depolymerization of lignin to well-defined chemicals and their further deoxygenation to arenes are extremely attractive. Based on our previous results that Nb2O5 species can promote the cleavage of C–O bonds and the synergistic effect between Ru and Nb2O5 species led to the direct transformation of lignin into arenes over a Ru/Nb2O5 catalyst [Nat. Commun., 2017, 8, 161041], the importance and influence of ruthenium particle size need to be further studied. Herein, we report the different performances of Ru/NbOPO4 catalysts with various Ru particle sizes in the hydrogenolysis of a lignin model compound. This study shows that the catalytic activities and the product distributions strongly depend on the size of Ru nanoparticles (NPs): Ru NPs with smaller diameters (1.2 and 1.8 nm) have a higher activity for the cleavage of Caliphatic–O and Caromatic–O bonds, whereas Ru NPs with larger diameters (2.5 and 5.3 nm) show a much lower activity for C–O cleavage, especially for the Caromatic–O bond, resulting in totally different product distributions. Density functional theory (DFT) calculations revealed that the presence of step and edge sites in smaller Ru particles can significantly lower the barriers for both Caromatic–O and Caliphatic–O bond cleavage. This study provides a new way for catalyst design towards highly efficient and selective hydrogenolysis of lignin to useful aromatic chemicals.
研究领域:
催化化学
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材料科学
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可再生资源转化
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）