Inorganic Chemistry Frontiers
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2019
·Vol. 7
·期 1
·82-90
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IF 5.934
Xiao Chen,Shuhua Han,Dongdong Yin,Changhai Liang
Based on the isolation of the active sites in the crystal structure as well as the strong alteration of the electronic structure in comparison to elemental metals, metal silicides as typical intermetallic compounds have boosted their applications in catalysis. Heterogeneous Ni2Si/SiCN as a promising and low-cost catalyst alternative to noble-metals has been successfully synthesized via the chemical modification of a polysilazane precursor at a molecular level by the use of metal complexes followed by its temperature-programmed pyrolysis. In the one-pot tandem synthesis of imines and secondary amines via the reductive coupling of nitrobenzene and benzaldehyde, the as-prepared Ni2Si/SiCN-1000 catalyst exhibits excellent catalytic performance (conversion >99% and selectivity to aromatic amine >92%) and excellent recyclability under optimal reaction conditions. Due to the reduction induction support–metal strong interactions and the formation of intermetallic Ni2Si, the electronic structure of the metallic Ni active site has been modified, which may tone the catalytic performance and enhance the stability of the catalyst.
研究领域:
材料科学
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催化化学
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DOI
高影响因子
JOURNAL OF CATALYSIS
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2023
·
IF 7.3
Ziliang Yuan,Guanghui Wang,Xun Li,Yurong He,Pan Wang,Francesco Mauriello,Zehui Zhang
Earth-abundant metal catalysts, especially Ni, are highly favourable in heterogeneous reactions compared with noble metal ones. Herein, Ni nanoparticle catalysts supported on Vulcan carbon (VCX) support were prepared through a simple impregnation-reduction method and utilized for the acceptorless dehydrogenation of primary amines to secondary amines. The best performance was achieved with Ni (A) /VXC with Ni particle size of 11.9 nm at 150 °C. Smaller or larger particle sizes resulted in a lower TOF, indicating a structure-sensitive activity. This work may serve as inspiration for further investigation into acceptorless dehydrogenation using non-noble metal catalysts.
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
ACS Catalysis
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2025
·
IF 13.1
Jia-qi Bai,Mei Ma,Huangfei Liu,Zhangkai Qian,Durui Liu,Yuncai Zhao,Yijing Gao,Jingshuai Chen,Mengdie Cai,Song Sun
The hydrogenation of nitriles is an environmentally friendly and atom-economical route to prepare high-value amines; however, it is still a challenge to control selectivity because of the occurrence of hydrogenation, self-coupling, and hydrogenolysis reactions during the hydrogenation process. It is highly desirable to develop efficient non-noble-metal catalysts for the hydrogenation of nitriles to secondary amines, although several noble metal catalysts have been reported. Herein, we successfully prepared a Cu–Ni/W20O58 catalyst and found that the Cu4.4–Ni0.6/W20O58 catalyst showed a 92.3% yield with initial TOFs of 270.0 h–1 at 373 K and 3 MPa H2 for the hydrogenation of benzonitrile (BN) to dibenzylamine (DBA), which was much superior to that of the monometallic Cu4.4/W20O58 and Ni0.6/W20O58 catalysts. Moreover, the Cu4.4–Ni0.6/W20O58 catalyst could be reused at least 4 times and was effective for the hydrogenation of various nitriles with superior selectivity to secondary amines. Furthermore, the reaction mechanism of BN hydrogenation for the Cu–Ni alloy of Cu4.4–Ni0.6/W20O58 was proposed on the basis of spectroscopic studies such as XRD, TPR, TEM, XAFS, and XPS, kinetic studies such as the effect of BN concentration and H2 pressure, the isotopic effect of hydrogen, and the effect of the reaction temperature and DFT calculations. The rate-determining step was the hydrogenation of benzylidenamine (BI) to the half-hydrogenated intermediate by one H atom over the Cu4.4–Ni0.6/W20O58 catalyst. The Ni–W20O58 interface was responsible for the adsorption and activation of BN, and the electron-rich Cu acted as the site for H2 dissociation; the synergistic effect of Cu and Ni led to the superior catalytic performance of the Cu4.4–Ni0.6/W20O58 catalyst.
研究领域:
催化化学
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材料科学
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环境化学
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产品关联
DOI
高影响因子
Journal of CO2 Utilization
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2018
·
IF 5.503
Yu-Nong Li,Xiao-Fang Liu,Liang-Nian He
The oxazolidinone as one kind of annular CO 2 derivatives has been hydrogenated by a new catalytic system Pd/C-TMGPEG 150 Me (polyethylene glycol-functionalized 1,1,3,3-tetramethyl guanidine), affording two valuable products i.e. formic acid and the corresponding secondary alkyl-(2-arylethyl)amines in the high yields of 89% and 98%, respectively. This hydrogenation can be carried out smoothly under relatively mild conditions of 60 °C, 4 MPa of H 2 with a liquid/solid carbon source (oxazolidinone) instead of high pressure CO 2 . The notable results can be successfully obtained even at room temperature under atmospheric H 2 pressure. This one stone two bird strategy is applicable to series of 5-aryl-2-oxazolidinones and opens up a novel way of synthesizing linear secondary alkyl-(2-arylethyl)amines without the selectivity issues, and validates a potential alternative approach for indirect conversion of CO 2 to energy-related products formic acid, as oxazolidinones can be readily obtained from hydrogenation of CO 2 .
研究领域:
化学
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催化科学
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绿色化学
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DOI
高影响因子
Nano Research
·
2019
·Vol. 12
·期 7
·1625-1630
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IF 8.515
Tong Xuanjue,Cao Xing,Han Tong,Cheong Weng-Chon,Lin Rui,Chen Zheng,Wang Dingsheng,Chen Chen,Peng Qing,Li Yadong
Photocatalytic oxidation has been widely employed in organic synthesis, by virtue of the green, mild and simple reaction conditions as well as high selectivity. Introducing oxygen vacancies (OVs) with proper concentrations into the photocatalysts has been proven as an effective strategy to boost the catalytic performances. However, the currently used treatment method under high temperature at reducing atmosphere inevitably introduces a large number of OVs at the interior of the catalyst and serving as the recombination centers of carriers. To address this issue, here we develop a facile solvothermal process to prepare ultrathin BiOBr nanosheets with rich surface OVs. This method effectively decreases the bulk of the material and the ratio of interior OVs, rendering most of the OVs exposed on the surfaces which act as exposed catalytic sites and enhance the separation of carriers, therefore significantly elevates the photocatalytic performances. For the photo-oxidation reaction of secondary amines, under the conditions of visible light, ambient temperature and atmosphere, the BiOBr nanosheets featuring rich surface OVs deliver a doubled conversion compared to those with low OV concentrations, and a high selectivity of 99%, a high stability as the performance shows no reduction after 5 times of circular reaction.
研究领域:
材料科学
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催化化学
✓ 已验证
产品关联
DOI
高影响因子
ENERGY
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2022
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IF 8.857
Xiaobin Zhou,Chao Liu,Yinming Fan,Lihao Zhang,Shen Tang,Shengpeng Mo,Yinian Zhu,Zongqiang Zhu
Biphasic solvents have been widely studied for CO 2 capture due to their remarkable energy-saving potentiality. However, most existing biphasic solvents suffer from the high viscosity of their CO 2 -rich phase. This study proposed a novel low-viscous secondary amine-based nonaqueous biphasic solvent for CO 2 capture. With dimethyl sulfoxide (DMSO) as the organic diluent and pentamethyldiethylenetriamine (PMDETA) as the phase splitting agent, the secondary amine of 2-methyl-ethynolamine (MAE) was proved to be the optimal candidate for preparing the biphasic solvent. The MAE/DMSO/PMDETA (M/D/P) biphasic solvent could realize a high CO 2 loading of 0.84 mol mol −1 and the viscosity of its CO 2 -rich phase was only 8.87 mPa s, which was significantly lower than that of most reported biphasic solvents. The reaction mechanism analysis revealed that M/D/P absorbed CO 2 to form products of protonated amines, carbamate, and carbamic acid species. Since the products were polar and showed a stronger affinity to polar DMSO, while less polar PMDETA was isolated, thereby resulting in a phase change. Thermodynamics analysis showed that the M/D/P biphasic solvent could sharply cut down the sensible heat and latent heat during CO 2 desorption. Eventually, the total regeneration energy penalty of M/D/P was significantly reduced by 46.3% compared with the benchmark aqueous MEA solution.
研究领域:
化学工程
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环境科学
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产品关联
DOI
高影响因子
CATALYSIS TODAY
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2022
·
IF 6.562
Hengwei Wang,Yue Lin,Junling Lu
Hydrogenation of nitriles represents an efficient and environmentally benign route to synthesis of high-value amines. However, the amine selectivity is commonly low, and the mixtures of amines, imines, and even low-value hydrogenolysis byproducts are generally obtained. Herein, we report that overcoating of Pd and Pt catalysts with an ultra-thin NiO x layer via atomic layer deposition enables to close up the undesired hydrogenolysis pathway completely and to prompt a yield of secondary amines drastically to 96% under mild conditions in the hydrogenation of nitriles. The NiO x -coated catalysts also exhibit a much higher recyclability than the uncoated ones. Through detailed structural characterization and control experiments of catalytic performance tests, we show that the NiO x overcoat plays at least three important roles in the promotion of catalytic performance: (i) Enhancement of the adsorption of both imine intermediates and primary amines, to stimulate the subsequent condensation of these two molecules to form secondary amines exclusively with a high activity; (ii) Isolation of large Pd and Pt ensembles to inhibit the hydrogenolysis byproduct; and (iii) Acting as a protective layer to stabilize metal nanoparticles against leaching, and to prevent the formation of undesired metal hydride phase, thus leading to a significant improvement in catalytic stability. These findings provide a robust methodology for directing selective hydrogenation of nitriles to secondary amines exclusively, and the insights here would facilitate the rational design of oxide overcoating layers for advanced catalysis.
研究领域:
催化化学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
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2017
·Vol. 41
·期 20
·11991-11997
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IF 3.269
Liang Jiang,Peng Zhou,Zehui Zhang,Quan Chi,Shiwei Jin
The application of earth-abundant transition metal catalysts in the mild and selective synthesis of secondary amines via the reductive amination method is very challenging. In this regard, we have developed a new method for the reductive amination of carbonyl compounds with nitro compounds over a heterogeneous Co–nitrogen (Co–Nx) catalyst under mild conditions (110 °C and 10 bar H2). This method afforded the corresponding secondary amines with the yields of 43.7–100% at 110 °C and under 10 bar H2 pressure. Kinetic studies revealed that the hydrogenation of imines was the rate-determining step with much higher activation energy than the first step of the hydrogenation of nitro compounds. To the best of our knowledge, no such non-noble heterogeneous catalyst that shows very high catalytic activity under mild conditions (110 °C and 10 bar H2) has been reported to date. This promising cheap heterogeneous catalyst allows an efficient domino reductive amination of carbonyl compounds with nitro compounds.
研究领域:
有机化学
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催化化学
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环境化学
✓ 已验证
DOI
高影响因子
ACS Catalysis
·
2019
·
IF 12.221
Yunrui Zhang,Yongjun Gao,Siyu Yao,Siwei Li,Hiroyuki Asakura,Kentaro Teramura,Haijun Wang,Ding Ma
MoS2 catalysts with abundant S and Mo defects have been developed for the one-pot reductive amination of nitro compounds with aldehydes to synthesize secondary amines. The combination of multiple structural characterizations demonstrates that the density of S vacancies can be tuned by changing the thermal sublimation temperature. The experimental results and DFT calculations demonstrate that S vacancies on the surface of MoS2 are the active sites for the hydrogenation of the intermediate imines to the final products secondary amines.
研究领域:
催化化学
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材料科学
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计算化学
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
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2024
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IF 8.1
Yikang Huang,Liang Zhu,Ning Zeng,Pinjie Wang,Ge Gao,Wufeng Jiang,Xiaoshan Li,Liqi Zhang
Developing amine solutions with low energy consumption is of great significance for CO 2 capture technology. Currently most of studies focused on reducing sensible heat and heat of vaporization by anhydrous absorbents and phase-change absorbents based on amines. It should be noted that CO 2 reaction heat of amines is also an important section for energy consumption. In this work, CO 2 reaction heat of 7 secondary amines was investigated aiming to reveal structure–activity relationship between CO 2 reaction heat and the length of the carbon chain, methyl side chain and hydroxyl group in secondary amines. The CO 2 reaction heat of 7 secondary amines was directly measured by microcalorimeter with high precision. Results showed that increasing the length of carbon chain, introducing hydroxyl group and removing methyl side chain in secondary amines could increase CO 2 reaction heat. The lengthening of carbon chain and the addition of the hydroxyl group led to an increase in the electronegativity in N atom of the secondary amines, thereby increasing the reactivity and reaction heat of the secondary amine. The steric hindrance caused by methyl side chain reduced the reactivity and reaction heat of secondary amine. This study could help to screen and develop energy-saving secondary amine absorbents for CO 2 capture.
研究领域:
化学工程
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环境科学
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物理化学
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING SCIENCE
·
2024
·
IF 4.1
Ding Wei,Jialuo Xiang,Qinlan Luo,Yu Mao,Xiao Luo,Yangqiang Huang,Zhiwu Liang
To study the reaction kinetic of CO 2 absorption in aqueous secondary amine + tertiary amine blends, 1-Diethylamino-2-propanol (DEA2P) and 1-Dimethylamino-2-propanol (DMA2P) were selected to form aqueous amine blended solutions with 2-(Ethylamino) ethanol (EAE), respectively. The reaction kinetics of CO 2 absorption in aqueous EAE/DEA2P solutions and EAE/DMA2P solutions were explored using the stopped-flow apparatus, and the reaction mechanism was then explored by Density Functional Theory (DFT) calculations. Based on the zwitterion mechanism and the base-catalyzed hydration mechanism, experimental reaction kinetics models were established. It was found that in secondary amine + tertiary amine blends, tertiary amines played the key role of the proton acceptor in step of zwitterion deprotonation. With the increase of the chain length of tertiary amine, the CO 2 absorption rate increased. Through analysis, it was found that the main reason for the increased CO 2 absorption rate was the presence of H-bond or the stronger proton affinity of N atom.
研究领域:
化学工程
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
MACROMOLECULES
·
2022
·
IF 6.057
Fengbiao Chen,Fei Gao,Xinru Guo,Liang Shen,Yangju Lin
Polymer networks embedded with dynamic covalent bonds have been demonstrated to be capable of network reconfiguration. This reprocessability is often related to the network dynamics or flowability, the precise control of which highly depends on the underlying chemistry. Particularly, vitrimer materials flow at a constant crosslinking density because of the associative dynamic chemistry involved. Here, we report the fabrication of enamine-one vitrimers through an amino-yne click reaction using secondary amine substrates. Compared with primary amines, the secondary amine-based amino-yne click reaction is mild and yields less gel content (70 vs 97%) in our curing system. By modulating the substituents of the secondary amine, we show that the activation energy of the exchange reaction increases (52–90 kJ/mol) with increasing steric hindrance (piperidyl ∼ methyl < ethyl < isopropyl < tert-butyl), and a similar trend was observed in the vitrimer networks. Interestingly, piperidine exhibits reactivities (including the yielded gel content and network dynamics) comparable to that of primary amines because of the less steric hindrance related to the constrained cyclic structure. This study not only enriches the scope of amine substrates for vitrimer fabrication but also offers a convenient means to tune the network dynamics through substrate choices or combination strategies (i.e., mixing primary and secondary amines or various secondary amines).
研究领域:
材料科学
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化学
✓ 已验证
产品关联
DOI
高影响因子
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