EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
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2022
·Vol. 2022
·期 33
·e202200316
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IF 3.261
Yong Wang,Hui Wang,Qifan Yang,Shihua Xie,Hongjun Zhu
Graphical Herein, palladium(II)-catalyzed halogenation of 2-phenylquinazolines using N -halosuccinimides as halogen sources was described via C−H activation under mild reaction conditions. A series of halogen-substituted 2-arylquinazolines were synthesized through C−H functionalization. An efficient quinazoline-assisted ortho -halogenation of 2-arylquinazolines has been developed using N -halosuccinimides as halogen sources with Pd(II)-catalyzed C−H bond activation. No additional ligand and oxidant are required. This protocol is highly regioselective and applicable to a broad range of quinazoline substrates bearing different functional groups, giving yields of up to 98 %. The mechanism of the quinazoline ortho -halogenation was investigated by comprehensive experimentation.
研究领域:
有机化学
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合成化学
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DOI
高影响因子
JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY
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2019
·Vol. 95
·期 3
·798-805
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IF 2.659
Dan Luo,Shengnan Liu,Wang Yin,Shuqian Xia
BACKGROUND Fast pyrolysis of lignocellulosics has provided an abundant sugar source for production of value-added chemicals, and levoglucosan is the most representative sugar in pyrolysis liquid (bio oil). This paper explored the potential for producing methyl lactate from levoglucosan by employing the mixed catalysts of zeolite tin beta (Sn-Beta) and zeolite hydrogen beta (H-Beta). RESULTS Under the optimal conditions (at 200 °C and mixed catalysts with H-Beta:Sn-Beta ratio of 1:5), the yield of methyl lactate obtained from levoglucosan conversion was as high as 35%. And the yield was comparable to that of methyl lactate obtained from glucose conversion under the similar conditions (at 200 °C and pure Sn-Beta). In order to investigate the reason, a contrasting experiment with glucose as substrate also was carried out with the mixed catalysts. The results indicated that during the levoglucosan conversion process, ‘the methanolysis of levoglucosan’ was likely to compete with ‘the dehydration of glucose’ for the Brønsted acid sites of H-Beta. In addition, the catalytic functions of H-Beta and Sn-Beta, and the reaction pathway were deeply investigated through tracking and comparing the conversion of levoglucosan over mixed H-Beta/Sn-Beta and over pure Sn-Beta catalysts, respectively. CONCLUSION The appropriately lower ratio of H-Beta:Sn-Beta and relatively higher temperature were favorable for the reaction. H-Beta containing Brønsted acid could remarkably accelerate the conversion of levoglucosan and methyl-glucosides to glucose. Sn-Beta containing Lewis acid mainly promoted the retro-aldol condensation of glucose and formation of methyl lactate. © 2019 Society of Chemical Industry
研究领域:
化学工程
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生物质能
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催化化学
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高影响因子
APPLIED ORGANOMETALLIC CHEMISTRY
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2016
·Vol. 30
·期 8
·680-683
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IF 2.452
Lulu Wang,Minxin Yang,Xiaochong Liu,He Song,Lu Han,Wenyi Chu,Zhizhong Sun
A bidentate-chelation assistant palladium-catalyzed direct C-H cyanation of picolinamides with TMSCN is described. The reaction of various derivatives gave the corresponding cyanated products in moderate to good yields under mild conditions. In addition, the cyanated product could transform into some valuable functional groups in good yields. Copyright © 2016 John Wiley & Sons, Ltd.
研究领域:
有机化学
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药物化学
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高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
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2023
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IF 22.1
Haiying Xu,Zhaoliang Wang,Hehua Liao,Dongmiao Li,Jinni Shen,Jinlin Long,Wenxin Dai,Xuxu Wang,Zizhong Zhang
Photocatalytic converting CO 2 into C 2 products is highly desirable but is extremely sensitive to catalyst structure. In this work, Ti-H species and oxygen vacancies are simultaneously integrated on hydrogenated SrTiO 3 surface by thermally treating with NaBH 4 , which promotes the activation of CO 2 into HCOO - and CO* intermediates. The proximity of oxygen vacancies and Ti-H species contributes to the C-C coupling of intermediates into acetylene (C 2 H 2 ) products. To the best of our knowledge, this is the first example for the photocatalytic CO 2 reduction into C 2 H 2 main products. The optimal hydrogenated SrTiO 3 has the C 2 H 2 yield of 39.0 μmol·g −1 with a 76.0 % selectivity among C 2 products. Therefore, this work provides an approach of designing the adjacent active sites for photocatalytic CO 2 conversion into C 2+ products.
研究领域:
材料科学
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环境科学
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高影响因子
JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY
·
2024
·
IF 3.1
Guanru Chen,Fengjian Chu,Shuheng Zhang,Wangyu Li,Shiwen Zhou,Wei Wei,Weiwei Chen,Xiaozhi Wang,Lei Yue,Hongru Feng,Yanli Cui,Yuanjiang Pan
C–H bond ortho-substitution reaction has always been a significant and challenging topic in organic chemistry. We proposed a synthesis method based on microwave plasma torches. High-resolution mass spectrometry was used to monitor rapid reaction products. 2-Alkylbenzimidazole can be formed through the reaction of phenylnitrenium ion and nitriles on a millisecond scale. This reaction can achieve the one-step formation of benzimidazoles from benzene ring single-substituted compounds without the addition of external oxidants or catalysts. A similar C–H bond activation reaction can be accomplished with ketones. Meanwhile, the microwave plasma reactor was modified, and the resulting 2-methylbenzimidazole was successfully collected, indicating the device has good application potential in organic reactions such as C–H bond activation reaction.
研究领域:
有机化学
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合成化学
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分析化学
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DOI
PubMed
高影响因子
Nanomaterials
·
2019
·Vol. 9
·期 7
·1051
·
IF 4.034
Xiu Wang,Zhihuai Yu,Liang Jiao,Huiyang Bian,Weisheng Yang,Weibing Wu,Huining Xiao,Hongqi Dai
Hexagonal boron nitride (h-BN)-based heat-spreading materials have drawn considerable attention in electronic diaphragm and packaging fields because of their high thermal conductivity and desired electrical insulation properties. However, the traditional approach to fabricate thermally conductive composites usually suffers from low thermal conductivity, and cannot meet the requirement of thermal management. In this work, novel h-BN/cellulose-nano fiber (CNF) composite films with excellent thermal conductivity in through plane and electrical insulation properties are fabricated via an innovative process, i.e., the perfusion of h-BN into porous three dimensional (3D) CNF aerogel skeleton to form the h-BN thermally conductive pathways by filling the CNF aerogel voids. When at an h-BN loading of 9.51 vol %, the thermal conductivity of h-BN/CNF aerogel perfusion composite film is 1.488 W·m−1·K−1at through plane, an increase by 260.3%. The volume resistivity is 3.83 × 1014Ω·cm, superior to that of synthetic polymer materials (about 109~1013Ω·cm). Therefore, the resulting h-BN/CNF film is very promising to replace the traditional synthetic polymer materials for a broad spectrum of applications, including the field of electronics.Keywords:CNF aerogel;perfusion;h-BN;thermal conductivity;electrical insulation
研究领域:
材料科学
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电子工程
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DOI
PubMed
高影响因子
ACS Sustainable Chemistry & Engineering
·
2021
·
IF 8.198
Changzhou Chen,Peng Liu,Haihong Xia,Jianchun Jiang,Xiaohui Yang,Minghao Zhou
Lignin is an abundant source of aromatics with low effective hydrogen-to-carbon ratio (H/Ceff), and the depolymerization of lignin provides significant potential for producing liquid products with an improved H/Ceff value. In this work, the catalytic conversion of lignin monomers, dimer, trimers, and realistic lignin over spherical MOF-derived NiMo@C catalysts was well established, to get liquid fuels with a higher H/Ceff. The optimal ratio of the Ni4Mo1@C catalyst exhibited good hydrodeoxygenation activity and stability for the hydrotreatment of lignin model compounds and lignin. The addition of Mo facilitated the decrease of the particle size of a spherical structure, strengthened the electron-transfer capability between metals Mo and Ni, and enhanced the acid strength. All of these factors contributed to higher hydrodeoxygenation activity in the hydrotreatment process. Up to 100% conversion and 90% yields of ethylcyclohexane and cyclohexanol with H/Ceff values of 2.0 and 1.667, respectively, were obtained. The Ni4Mo1@C catalyst achieved a decrease of the oxygen element and an increase of H/Ceff and HHV values. The physicochemical characterizations were performed by various means including X-ray diffraction (XRD), scanning electronic microscopy (SEM), transmission electron microscopy (TEM), H2-temperature-programmed reduction (H2-TPR), NH3-temperature-programmed desorption (NH3-TPD), pyridine-infrared spectroscopy (Py-IR), inductively coupled plasma emission spectrometer (ICP), and Raman and X-ray photoelectron spectroscopy (XPS) analyses, which definitely elucidated the formation of a synergistic effect between metals Mo and Ni. Additionally, a control experiment also illustrated the synergistic effect that facilitated the occurrence of the hydrotreatment process under lower temperatures after the addition of metal Mo. Based on the optimal reaction condition (240 °C, 4 h, 2.0 MPa H2), both lignin and its monomers/dimers/trimers could be effectively hydrotreated to afford liquid products with improved H/Ceff value compared to raw lignin.
研究领域:
能源化学
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催化化学
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DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
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2024
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IF 13.3
Shuangxi Lin,Longchen Gong,Ning Zhao,Huibo Zhao,Feigang Zhao,Yang Bai,Zhenhua Li,Wen Liu
Modulating metal-support interactions is critical for improving catalytic activity and product selectivity for CO 2 hydrogenation. Such modulation can be achieved by modifying the metal nanoparticles as well as the supports. Here, we prepared a novel catalyst, in which Ni nanoparticles were dispersed on CeO 2 and hexagonal boron nitride (h-BN) hybrid supports. The introduction of h-BN to Ni/CeO 2 -BN effectively improves the dispersion of Ni nanoparticles. More importantly, the abundant Ni-CeO 2 interfacial sites with enriched oxygen vacancies are formed over h-BN edge sites. The dispersed Ni species are anchored on CeO 2 via a unique interfacial structure, with electron-rich Ni (Ni δ− ) species. At the interfacial sites on Ni/CeO 2 -BN, the synergy between oxygen vacancies and Ni δ− , which enhances CO 2 activation and H 2 dissociation, respectively, renders superior catalytic performance for CO 2 methanation. In situ DRIFTS suggests formate as key rate-limiting intermediates on Ni-CeO 2 sites, while the formation of B-H bonds further promotes hydrogen activation and subsequently the catalytic performance. The modulation of metal-support interactions by spatial confinement effect by BN offers a new paradigm for designing metal/oxide catalysts for chemical transformations that requires bifunctionality as CO 2 hydrogenation.
研究领域:
催化化学
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材料科学
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DOI
高影响因子
CATALYSIS LETTERS
·
2019
·Vol. 149
·期 8
·2078-2088
·
IF 2.372
He Xiaoxia,Chen Yu,Liu Ya,Fang Lina,Chen Zeng,Ji Hongbing
Abstract A series of metal-modified hierarchical M/H-ZSM-5 catalysts were prepared for catalytic conversion of cellulose in an aqueous medium. Characterization of the catalysts showed that the impregnation of metal into H-ZSM-5 did not change the basic framework and pore structure of H-ZSM-5, but it decreased the total acidity. Analysis of the products indicated that the catalysts significantly affected products distribution. When Co/H-ZSM-5 and Fe/H-ZSM-5 were used as the catalysts, the yields of lactic acid and cyclic ketones obviously increased. At last, a recommendable catalytic transformation pathway of cellulose over M/H-ZSM-5 was proposed on the basis of the obtained experimental results and the published literatures. Graphical Abstract In this paper, a series of metal-modified hierarchical M/H-ZSM-5 (M = Ce, Co, Ga, and Fe) catalysts were prepared and employed in catalytic conversion of cellulose in aqueous media to examined the products distribution of cellulose catalytic conversion. Based on our results and previous works, the plausible general reaction pathways of cellulose over M/H-ZSM-5 were proposed.
研究领域:
化学工程
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催化材料科学
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DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
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2022
·
IF 16.744
Tian-Yu Liu,Cong Wang,Yong-Zhe Han,Chang Bai,Hai-Tao Ren,Yong Liu,Xu Han
Bi 2+x WO 6 are a group of reactive photocatalysts in the photooxidation of various contaminants. However, their catalytic reactivity in the persulfate (PS)-based oxidation processes in the absence of light is still unknown. In this study, Bi 2.15 WO 6 shows a high reactivity in the catalytic oxidation of bisphenol A (BPA) by PS in the absence of light under alkaline conditions, and 20 mg L -1 BPA can be rapidly removed within 30 min at pH 10.0 with the low stoichiometry ratio of 1.79 between consumed PS and removed BPA. Characterizations of the oxidation products indicate that 98.4% of soluble BPA has been oxidatively polymerized to BPA polymers, instead of being oxidized to CO 2 and H 2 O. FTIR, Raman, XPS and electrochemical analyses confirm that surface Bi(III) is the reactive site for the adsorption of BPA and PS, which then initiates reactions between BPA and PS. DFT calculations reveal that the O-O bond in PS is moderately activated via the nonradical pathway after adsorbing on Bi(III), instead of being decomposed to SO 4 •− , followed by H-abstraction from BPA by the activated PS with the formation of phenoxyl radicals and the subsequent polymerization to BPA polymers. The apparently lower energy barrier from adsorbed BPA (Δ G = 0.056 eV) than that from dissolved BPA (Δ G = 0.263 eV) further reveals that H-abstraction from adsorbed BPA to the activated PS on the surface of Bi 2.15 WO 6 is more favorable than that from dissolved BPA. This study gives new insight on the efficient removal of recalcitrant contaminants via the H-abstraction pathway.
研究领域:
环境科学
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化学工程
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DOI
高影响因子
CONSTRUCTION AND BUILDING MATERIALS
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2023
·
IF 7.4
Chenchen Xiong,Yulin Wang,Yang Zhou,Xingyu Liu,JinHui Tang,Pan Feng
An ordered structure and high mechanical property of calcium silicate hydrate (C-S-H) gel has been always pursued in the field of cementitious materials. In this paper, compacted and layer-by-layer stacking C-S-H plates were fabricated based on Layer-by-Layer (LBL) method and H-cell penetration (HCP) method through cation exchange membrane templating. This new way changed the randomly packing structure of traditional C-S-H, and synthesized a high-orderly C-S-H platelets with denser structure. Based on molecular dynamics simulations, it can be attributed to the strong adsorption and nucleation sites contributed by sulfonic acid groups on the cation exchange membrane. Besides, AFM indentation experiments indicate this C-S-H owns significantly higher elastic modulus than traditional C-S-H, while the mechanical properties can be further increased by the addition of PVA and the regulation of reaction time. This new type C-S-H may pave the way to the preparation of high-performance concrete in the future.
研究领域:
材料科学
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土木工程
·
化学工程
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产品关联
DOI
高影响因子
ACS Nano
·
2025
·
IF 16
Shengxi Li,Yanxin Shang,Xuening Ren,Anqi Zhao,Nan Chen,Li Li,Feng Wu,Renjie Chen
Aqueous lithium-ion batteries (ALIBs) have attracted increasing attention for their inherent safety and environmental benefits. However, the narrow electrochemical stability window of water (1.23 V) imposed by hydrogen evolution reaction (HER) and high melting point (0 °C) critically limits the energy density and low-temperature operation. In this work, we report an electrolyte design principle that water activity can be suppressed by strengthening the O–H bonds between water molecules and regulating the pH. A strong polar solvent N,N-dimethylformamide (DMF) interacts with H2O through intermolecular hydrogen bonds, thereby reinforcing the covalent O–H bonds of water. Meanwhile, KOH renders the electrolyte alkaline, inhibiting water dissociation kinetics and consequently raising the HER overpotential. The designed LD1.7W0.6–KOH electrolyte exhibits a freezing point below −82 °C and expanded electrochemical stability window of 4.3 V. The 2.5 V aqueous LiMn2O4/Li4Ti5O12 full cell delivers 2000 cycles at a rate of 6 C with a Coulombic efficiency of 99% at 30 °C and over 1950 cycles at 0 °C. This work offers atomic-level insights into alkaline HER while providing guidance for advancing low-temperature aqueous batteries by tuning the electrolyte structures.
研究领域:
材料科学
·
电化学
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DOI
PubMed
高影响因子
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