Molecular Catalysis
·
2018
·
IF 0
Yueqing Wang,Xiaohai Yang,Hongyan Zheng,Xianqing Li,Yulei Zhu,Yongwang Li
The mechanism for the formation of furfural by dehydration of d -fructose via selective carbon-carbon (C C) bond cleavage was investigated over beta zeolite (Hβ). Several different pore size zeolites were employed to determine the shape selectivity of fructose isomers. Zeolitic pore sizes that smaller than the kinetic diameter of cyclic fructose also produced yield furfural (∼22.5%), while the high yield (66.0%) of hydroxymethylfurfural (HMF) can be achieved over large pore zeolite (USY zeolite), which could accommodate the cyclic fructose. These results indicated that the furfural formation likely began with acyclic fructose. In situ 13 C NMR and GC MS studies, using labeled 13 C-1-fructose as substrate, suggested that the conversion of fructose to furfural involved with splitting of the C5-C6 bond. Furthermore, the C1 compound from the cleavage of C C bond was identified as formaldehyde, inferring that the selective scission of C C bond was ascribe to the retro-aldol reaction. Interestingly, in situ NMR studies implied that the acyclic fructose mainly derived from pyranose forms. In addition, compared with glucose, fructose directly converted to furfural at the higher yield and reaction rate.
研究领域:
催化化学
·
有机化学
✓ 已验证
产品关联
DOI
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2025
·
IF 8.5
Liang Wei,Keyu Qu,Jun Huang,Zhe Li,Xianyi Ning,Xiande Yang,Meng Li,Hongxi Zhang,Jing Yang
Lignin, one of the most prevalent organic polymers on Earth, is predominantly produced as a byproduct in the pulp and paper industry and is frequently disposed of as waste, posing substantial environmental challenges. The carbon‑carbon (C C) bonds in lignin are notably stable, complicating catalytic activation and cleavage. This study presents a significant advancement in the visible-light-driven cleavage of lignin's recalcitrant C C bonds (specifically the β-1 type) utilizing mixed-phase TiO 2 (P25) under ambient conditions. In contrast to conventional approaches that emphasize C O bond scission, the P25 catalyst achieves a 93 % conversion rate and 87 % selectivity towards benzaldehyde from 1,2-diphenylethanol without the use of noble metals or complex modifications. Density Functional Theory (DFT) calculations reveal that the rutile {110}/anatase {101} interface lowers the energy barrier for ·O₂ − generation, corroborating experimental selectivity trends. The synergy between these facets facilitates interfacial charge transfer, generating superoxide radicals (·O₂ − ) as the dominant reactive species for C C activation. When applied to native lignin, β-1 and β-β bonds have been completely broken, with over 70 % of β-5 bonds also cleaved. In contrast, only 3 % of β-O-4 bonds were broken, validating scalability beyond model compounds. This work provides a solar-driven, metal-free route to valorize lignin waste, addressing both environmental and energy challenges.
研究领域:
环境科学
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材料科学
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有机化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ACS Catalysis
·
2019
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IF 12.221
Liu Yang,Tingting Yan,Chuanming Wang,Weili Dai,Guangjun Wu,Michael Hunger,Weibin Fan,Zaiku Xie,Naijia Guan,Landong Li
The formation of the initial carbon–carbon (C–C) bonds in the methanol-to-hydrocarbon (MTH) conversion on acidic zeolite has been hotly debated for decades. Recently, the formation of surface-bound acetyl groups involving C–C bonds during the initial period of the MTH conversion has been disclosed. Understanding the exact C–C bond-containing intermediates triggering the MTH conversion and the critical roadmap of the MTH conversion is essential for the further development of this important reaction. Herein, acetaldehyde from the hydrogenation of surface-bound acetyl species was identified to be responsible for triggering the MTH conversion on H-ZSM-5 zeolite. By combining kinetic studies, spectroscopic analyses, and theoretical calculations, the mechanism and roadmap of zeolite-catalyzed MTH conversion from the initial C–C bonds to the hydrocarbon pool compounds were clearly depicted.
研究领域:
化学工程
·
催化科学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2023
·
IF 7.4
Gui-Hua Wei,Ting Lu,Hai-Yan Liu,Jiao-Xuan Bai,Qian Wang,Guang-Yue Li,Ying-Hua Liang
Catalytic oxidation of cellulose using O 2 in aqueous solution shows important potential in the production of formic acid, an important industrial chemical as well as a promising hydrogen storage material. However, the microscopic oxidation mechanism is unclear due to the challenges in observing the cleavage of chemical bonds and the formation of transient intermediates and radicals. In this work, a combination of experimental and theoretical methods has been used to explore the catalytic oxidation mechanism of cellulose to formic acid. In the oxidation of cellulose, hydrogen cation plays a catalytic role and a decrease in pH improves the transformation with 57.7% formic acid obtained. Based on the model compound experiments, intermediate detection, molecular dynamics simulation, and density functional theory calculation, a mechanism is proposed, in which polyhydroxy aldehydes generated by cellulose hydrolysis undergo a continuous carbon–carbon bond cleavage-oxidation reaction to form formic acid with aldehyde moiety as the direct precursor. Acid has a catalytic effect on the cleavage-oxidation reaction of carbon–carbon bonds, reducing the energy barrier of carbon–carbon bond cleavage through generating epoxy intermediates. The aldehyde moieties are kept at an appreciable concentration, thereby increasing the yield of formic acid. Moreover, it is confirmed that the carboxyl moiety obtained by the oxidation of aldehyde is the precursor of the by-product CO 2 . These findings provide an in-depth insight into the production of bio-chemicals through carbon–carbon bond cleavage and a theoretical support for further process optimization.
研究领域:
化学工程
·
理论化学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL RESEARCH IN CHINESE UNIVERSITIES
·
2024
·Vol. 40
·期 1
·29-35
·
IF 3.1
Wang Lulin,Cheng Xiaomeng,Dong Minghua,Luan Sen,Wu Yuxuan,Han Buxing,Liu Huizhen
The challenge of breaking 5-5′ bonds in lignin, attributed to their high bonding energy, has prompted the development of a new transformation pathway. Biphenyl, an important model compound for lignin, contains these 5-5′ bonds, making it crucial to devise a strategy for their cleavage in lignin transformation. This study introduces a novel method for transforming biphenyl, involving selective hydrogenation to cyclohexylbenzene by Ni/SiO 2 catalyst, followed by its oxidation to phenol and cyclohexanone through a radical mechanism. Results demonstrate that the catalysts with small particles have strong catalytic activity, while there is little difference in selectivity. The reason for the high selectivity of cyclohexylbenzene is due to the limited adsorption of cyclohexylbenzene on Ni/SiO 2 . This work presents a fresh approach to breaking resilient C—C bonds in lignin.
研究领域:
化学工程
·
可再生资源利用
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催化科学
✓ 已验证
DOI
高影响因子
Nature Communications
·
2023
·Vol. 14
·期 1
·1-10
·
IF 16.6
Du Xinze,Fan Hongjun,Liu Shenglin,Zhang Z. Conrad
C−C bond forming reaction by alkylation of aryl rings is a main pillar of chemistry in the production of broad portfolios of chemical products. The dominant mechanism proceeds via electrophilic substitution of secondary and tertiary carbocations over acid catalysts, forming multiple aryl alkylation products non-selectively through all secondary and tertiary carbons in the alkyl chains but producing little α-C alkylation products because primary carbocations are poorly stable. Herein, we report that anatase TiO 2 (TiO 2 -A) catalyzes nucleophilic α-C alkylation of phenols with alcohols in high selectivity to simply linear alkylphenols. Experimental and computational studies reveal the formation of Ti=C− bond with the α-carbon of the alkyl group at oxygen vacancies of the TiO 2 -A surface. The subsequent α-C alkylation by selective substitution of phenol ortho- C−H bond is verified by deuterium exchanged substrate and DFT calculations.
研究领域:
化学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF ORGANIC CHEMISTRY
·
2022
·
IF 4.198
Hong-Li Huang,Juan Xu,Ya-Xin Fan,Qing-Qiang Su,Ji-Yuan Du,Ru-Fen Zhang,Yan-lan Wang,Honggang Hu,Fei Gao
The visible-light-promoted difunctionalization of alkenyl ketones has been developed for easy access of various tetralones, cyclopropane, or alkenyl migration compounds. With fac-[Ir(ppy)3] as the photocatalyst, alkenyl ketones captured the α-carbonyl alkyl radical and evolved through intramolecular cyclization and the elimination of a proton to give the difunctionalized products. This strategy is characterized by good yields, mild reaction conditions, and outstanding functional group tolerance.
研究领域:
有机化学
·
合成化学
✓ 已验证
DOI
PubMed
高影响因子
Fundamental Research
·
2021
·
IF 0
Liu Yang,Chang Wang,Weili Dai,Guangjun Wu,Naijia Guan,Landong Li
Understanding the complete reaction network and mechanism of methanol-to-hydrocarbons remains a key challenge in the field of zeolite catalysis and C1 chemistry. Inspired by the identification of the reactive surface methoxy species on solid acids, several direct mechanisms associated with the formation of the first C-C bond in methanol conversion have been recently disclosed. Identifying the stepwise involvement of the initial intermediates containing the first C-C bond in the whole reaction process of methanol-to-hydrocarbons conversion becomes possible and attractive for the further development of this important reaction. Herein, several initial unsaturated aldehydes/ketones containing the C-C bond are identified via complementary spectroscopic techniques. With the combination of kinetic and spectroscopic analyses, a complete roadmap of the zeolite-catalyzed methanol-to-hydrocarbons conversion from the initial C-C bonds to the hydrocarbon pool species via the oxygen-containing unsaturated intermediates is clearly illustrated. With the participation of both Brønsted and Lewis acid sites in H-ZSM-5 zeolite, an initial aldol-cycle is proposed, which can be closely connected to the well-known dual-cycle mechanism in the methanol-to-hydrocarbons conversion.
研究领域:
化学工程
·
催化科学
·
材料科学
✓ 已验证
产品关联
DOI
Journal of the American Chemical Society
·
2025
·
IF 15.6
Wen Yan,Tiantian Wu,Jia Liu,Zhe Zheng,Ming Ma
Electrolyte cation identity has been reported to influence the multicarbon (C2+) selectivity in CO2/CO electroreduction. However, most of the previous work for cation size effect is based on H-cell configurations, which may inadvertently distort the underlying mechanism of cation effect due to mass transport limitations, particularly for CO reduction. Here, using GDE-type flow electrolyzers, we report that the selectivity of total C2+ products on Cu is independent of alkali cation identity (Li+, Na+, K+, and Cs+) in the absence of the CO transport limitation. Notably, a high concentration of strongly hydrated cation (such as Li+) inhibits the total C2+ formation in CO reduction, whereas total C2+ selectivity is retained upon increasing concentrations of weakly hydrated cation (such as K+). Further investigations reveal that the CO coverage at a low cation concentration is almost independent of the cation identity, but the CO coverage at highly concentrated cations strongly relies on the alkali cation identity.
研究领域:
电化学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Nature Communications
·
2025
·Vol. 16
·期 1
·1-11
·
IF 15.7
Zhao Jun,Liu Bonan,Xiong Lunqiao,Liu Wenchao,Wang Duanda,Ma Wangjing,Jiang Litong,Yang Jianlong,Wang Ping,Xiao Tiancun,Zhao Sui,Edwards Peter P.,Tang Junwang
7 billion of 9.2 billion tons of plastic produced becomes waste while conventional catalytic plastic recycling methods are vulnerable with degraded performance and intensive energy input. Here, a hybrid Zn/b-ZnO catalyst, together with the specially-designed microwave reaction system, has achieved fast plastic waste upgrading under atmospheric pressure without using H 2 . Bifunctional ZnO acts as a microwave absorber and substrate catalyst, and in-situ formed Zn clusters promote C-C bond cleavage and nearly 100% upcycle landfilled plastic mixtures into lubricant base oil precursors and monomers. Unprecedented turnover number (250 g plastic g −1 catalyst ) of plastic depolymerisation and long-time stability over 50 successive cycles have been demonstrated, together with 8-time higher energy efficiency compared with conventional catalysis, indicating this strategy is an economical approach to efficient upcycling of plastics towards valuable products. Moreover, the catalyst can tolerate high contaminates, even the landfilled plastics can still be converted to lubricant base oil precursors, which has never been reported before.
研究领域:
化学工程
·
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
TETRAHEDRON
·
2022
·
IF 2.388
Wenfeng Zhong,Weiping Xu,Qin Yang,Terumasa Kato,Yan Liu,Keiji Maruoka
Using organosilicon compounds of the type Me 3 SiX (X = CN, N 3 , C n F 2n+1 , and halogens) and an amine base, alkylsilyl peroxides were generated in situ from the corresponding alkyl hydroperoxides . Subsequent in situ copper-catalyzed homolytic cleavage of the alkylsilyl peroxides afforded alkyl radicals, which were then trapped with a nucleophile X (X = CN, N 3 , C n F 2n+1 , and halogens) to furnish coupling products with new carbon–carbon, carbon–nitrogen, or carbon–halogen bonds in good to high yields. In addition, 1-(trimethylsilyl)morpholine can also be employed for the in-situ-generation of alkylsilyl peroxides, which are subsequently utilized for N-alkylation of amides, arylations , and borylations with high efficiency.
研究领域:
有机化学
·
合成化学
✓ 已验证
DOI
高影响因子
Journal of the American Chemical Society
·
2022
·
IF 16.383
Kang Ma,Tiantong Zhang,Ying Qin,Zhixin Hu,Zhixiang Sun,You Han,Dongbing Zhao,Hong-Ying Gao
Desilylative coupling involving C–Si bond cleavage has emerged as one of the most important synthetic strategies for carbon–carbon/heteroatom bond formation in solution chemistry. However, in on-surface chemistry, C–Si bond cleavage remains a synthetic challenge. Here, we report the implementation of C(sp2)–Si bond cleavage and subsequent C–C bond formation on metal surfaces. The combination of scanning tunneling microscopy and density functional theory calculation successfully reveals that the incorporation of the C–Br group on the arylsilanes is critical to the success of this desilylative coupling reaction on metal surfaces. Our study represents a promising approach for the removal of protecting silyl groups in on-surface chemistry.
研究领域:
表面科学
·
材料化学
·
理论化学
✓ 已验证
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）