JOURNAL OF CATALYSIS
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2019
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IF 7.723
Wenxiu Cao,Lu Lin,Haifeng Qi,Qian He,Zhijie Wu,Aiqin Wang,Wenhao Luo,Tao Zhang
The hydrogenation of levulinic acid (LA) to γ-valerolactone (GVL) is a key reaction for the production of renewable chemicals and fuels, wherein acid-resistant and robust catalysts are highly desired for practical usage. Herein, an ultra-stable 0.6 wt% Ir@ZrO 2 @C single-atom catalyst was prepared via an in-situ synthesis approach during the assembly of UiO-66, followed by confined pyrolysis . The Ir@ZrO 2 @C offered not only a quantitative LA conversion and an excellent GVL selectivity (>99%), but also an unprecedented stability during recycling runs under harsh conditions (at T = 453 K, P H2 = 40 bar in pH = 3 or pH = 1 aqueous solution). By thorough spectroscopy characterizations, a well-defined structure of atomically dispersed Ir δ+ atoms onto nano-tetragonal ZrO 2 confined in the amorphous carbon was identified for the Ir@ZrO 2 @C. The strong metal-support interaction and the confinement of the amorphous carbon account for the ultra-stability of the Ir@ZrO 2 @C.
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高影响因子
JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY
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2022
·Vol. 97
·期 10
·2805-2814
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IF 3.709
Shuaibin Zhang,Bochao Yan,Zhihui Chen,Suping Zhang
BACKGROUND Levulinic acid, an important platform compound, is extensively used in textiles, dyes, antifreeze, animal feed, solvents and food additives. However, the use of lignocellulosic biomass to produce levulinic acid is difficult because of poor accessibility to cellulose and low hydrolytic yield. Thus a viable hydrolysis strategy and a suitable catalyst must be developed. RESULTS In this study, a bifunctional solid acid catalyst (HTC-SO 3 H) containing both cellulose binding sites ( Cl, COOH and OH) and catalytic sites ( SO 3 H) was prepared by a carbonization–grafting–oxidization method. X-ray photoelectron spectroscopy and Fourier transform infrared characterization confirmed the existence of Cl and the successful modification of the SO 3 H grafted hydrothermal carbon. The hydrogen bonds formed between cellulose and the binding sites ( Cl, OH and COOH) in the catalyst showed synergistic effects with the catalytic sites ( SO 3 H), leading to efficient hydrolysis of the furfural residue. A total of 74.81% (non-magnetic) and 70.18% (magnetic) levulinic acid yields were obtained after hydrolysis at 190 °C and 180 min in γ-valerolactone–H 2 O (1:1, v/v). Magnetic catalysts were synthesized using a co-precipitation method. Catalysts were recycled without any obvious reduction in catalytic activity. CONCLUSION Using sucralose as a raw material, the as-synthesized bifunctional solid acid catalyst improved the accessibility to cellulose and increased levulinic acid yield. Moreover, the grafted SO 3 H formed by hydroxyl hydration condensation exhibited superior stability. This study provides a valuable strategy for the efficient hydrolysis of lignocellulosic biomass. © 2022 Society of Chemical Industry (SCI).
研究领域:
生物化学
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催化化学
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可再生能源
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RSC Advances
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2021
·Vol. 11
·期 25
·15054-15059
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IF 3.361
Miaojia Song,Xiaohui Di,Yu Zhang,Yongming Sun,Zhongming Wang,Zhenhong Yuan,Ying Guo
As an important bio-based chemical, methyl levulinate (ML) can be produced via enzymatic esterification of levulinic acid with methanol. A kinetic model is developed in this work based on the law of mass action and reaction reversibility, to investigate the effect of enzyme loading, alcohol/acid ratio and temperature on ML yield. Data analysis shows that newly developed binary regression is apparently more persuasive than the commonly used unitary regression. Kinetic study reveals: (1) rate constants of esterification/hydrolysis increase with increasing enzyme loading, while their ratio (equilibrium constant) remains invariant. (2) Methanol has no toxicity towards lipase, and hence, neither the rate constants of esterification/hydrolysis nor the equilibrium constant are affected by alcohol/acid ratio. (3) Both rate constants of esterification/hydrolysis and the equilibrium constant increase with temperature elevation, and their relationships agree with Arrhenius equation and Van't Hoff equation, respectively. (4) The esterification is endothermic and spontaneous. In total, the application of binary regression analysis for the developed model to study the enzymatic esterification kinetics is quite successful.
研究领域:
生物化学
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酶工程
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高影响因子
INORGANIC CHEMISTRY
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2021
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IF 5.165
Jie Li,Shuaiheng Zhao,Zhen Li,Dan Liu,Yingnan Chi,Changwen Hu
Catalytic transformation of levulinic acid (LA) to γ-valerolactone (γ-GVL) is an important route for biomass upgradation. Because both Bro̷nsted and Lewis acidic sites are required in the cascade reaction, herein we fabricate a series of H3PW12O40@Zr-based metal–organic framework (HPW@MOF-808) by a facile impregnation method. The synthesized HPW@MOF-808 is active for the conversion of LA to γ-GVL using isopropanol as a hydrogen donor. Interestingly, with the increase in the HPW loading amount, the yield of γ-GVL increases first and then decreases, and 14%-HPW@MOF-808 gave the highest γ-GVL yield (86%). The excellent catalytic performance was ascribed to the synergistic effect between the accessible Lewis acidic Zr4+ sites in MOF-808 and Bro̷nsted acidic HPW sites. Based on the experimental results, a plausible reaction mechanism was proposed: the Zr4+ sites catalyze the transfer hydrogenation of carbonyl groups and the HPW clusters promote the esterification of LA with isopropanol and lactonization to afford γ-GVL. Moreover, HPW@MOF-808 is resistant to leaching and can be reused for five cycles without significant loss of its catalytic activity.
研究领域:
催化化学
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可再生能源
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PubMed
高影响因子
ACS Catalysis
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2023
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IF 12.9
Yun Wang,Mengting Chen,Kaiyue Zhang,Haimei Wu,Jiale Wang,Yuran Cheng,Yingxin Liu,Zuojun Wei
Highly efficient transformation of renewable biomass and its derivatives into high-value-added chemicals and biofuels over non-noble-metal catalysts is attractive but challenging. Herein, we developed non-noble CoNi alloy nanoparticles confined in N-doped porous carbon (CoNi@NC) via simple pyrolysis of the metal–organic framework (MOF) precursor at 900 °C under an inert atmosphere. The as-obtained CoNi@NC catalyst exhibited higher performance than monometallic Co@NC and Ni@NC catalysts in the reductive amination of levulinic acid (LA) with benzylamine to N-benzyl-5-methyl-2-pyrrolidinone (BMP) under mild conditions of 130 °C and 3 MPa H2 for 6 h, achieving a full conversion of LA and a ≥ 99% yield of BMP. Detailed characterizations substantiated that multifunctional support and the significant synergistic effect between Co and Ni markedly enhanced the catalytic performance. Furthermore, CoNi@NC manifested outstanding recyclability (reusable 20 cycles without loss of activity), which was attributed to the well-dispersed CoNi alloy nanoparticles confined in the N-doped porous carbon and the anchoring of N species to metal nanoparticles. Additionally, the resultant CoNi@NC catalyst can be successfully applied in the one-pot transformation of LA/esters with amines/nitroarenes/nitriles to the corresponding N-substituted pyrrolidones, as well as the reductive amination of other carbonyl compounds with benzylamine to form N-heterocyclic compounds. Moreover, CoNi@NC enabled us to catalyze the continuous reductive amination of LA with amines in a trickle-bed reactor, which is a more promising, efficient, highly atomically economic, and green synthetic methodology, and exhibited excellent stability during the reaction over 36 h.
研究领域:
化学工程
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材料科学
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催化反应
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