- Pd-doped Ni nanoparticle-modified N-doped carbon nanocatalyst with high Pd atom utilization for the transfer hydrogenation of nitroarenes
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Palladium (Pd)-based catalysts with maximum utilization of the Pd atoms are attractive for hydrogenation reactions and conserving Pd resources. Herein, the highly dispersed Ni nanoparticle (NP)-modified mesoporous N-doped carbon (Ni/mCN) was successfully prepared by pyrolyzing a mixture of polyacrylonitrile, melamine and Ni(NO3)2·6H2O. Then, the resulting Ni/mCN material with highly dispersed metallic Ni NPs was treated with Pd(AcO)2, and Pd2+ was spontaneously reduced to metallic Pd by the Ni NPs, affording the PdNi NP-based catalyst (PdNi/mCN). The spontaneous reduction process deposits most of the Pd atoms on the surface of the Ni NPs, thus allowing for the maximum utilization of the noble metal Pd. The prepared mesoporous N-doped carbon support can not only provide more surface area to adsorb reaction substrates, but also enhances the accessibility of the active sites of PdNi NPs. The prepared PdNi/mCN nanocatalyst shows a very high catalytic activity for the transfer hydrogenation of nitroarenes using formic acid as the reductant under ambient conditions in aqueous solution, as compared to other Pd-based catalysts, probably because of the highly dispersed PdNi NPs and the maximum utilization of the Pd atoms, as well as the superior structure of mCN. Moreover, the PdNi/mCN nanocatalyst exhibits excellent recyclability and reusability, and the catalytic activity does not obviously decrease after ten reaction cycles. Therefore, we believe that this study should open a new frontier in the preparation of porous N-doped carbon-supported catalysts with maximum utilization of the noble metals for green and sustainable catalysis.
- Cui, Xueliang,Long, Yu,Zhou, Xia,Yu, Guiqin,Yang, Jin,Yuan, Man,Ma, Jiantai,Dong, Zhengping
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- In situ-formed cobalt embedded into N-doped carbon as highly efficient and selective catalysts for the hydrogenation of halogenated nitrobenzenes under mild conditions
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Inhibiting the dehalogenation is the main challenge when halogenated nitrobenzenes are hydrogenated using H2 as hydrogen source by heterogeneous catalysis. Herein, the earth-abundant cobalt embedded into N-doped carbon (Co@CN) catalysts were fabricated via one-pot pyrolysis of tannic acid, Co(NO3)2·6H2O and melamine, which can function as a highly efficient non-noble-metal-based heterogeneous catalyst for selective hydrogenation of halogenated nitrobenzenes. Chloroanilines, bromoanilines, and iodoanilines, including all regioisomers, could be obtained with excellent selectivity (typically >99 %) at 60 °C under 1 MPa H2, at almost complete conversion of the substrates. Additionally, Co@CN demonstrated excellent catalytic stability and could be reused at least five times without obvious loss of catalytic activity and selectivity. Therefore, the Co@CN catalyst exhibits vast potential for future industrial application in the selective hydrogenation of halogenated nitrobenzenes.
- Cao, Yueling,Liu, Kangkai,Wu, Chen,Zhang, Hepeng,Zhang, Qiuyu
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- A robust core-shell nanostructured nickel-iron alloy@nitrogen-containing carbon catalyst for the highly efficient hydrogenation of nitroarenes
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Currently, the catalytic selective hydrogenation of nitroarenes to produce aromatic amines is one of the most important key reactions in many fine chemical processes. In particular, non-noble-metal-catalyzed hydrogenation of nitroarenes represents more sustainable chemical processes. Here, we report a new robust and recyclable core-shell nanostructured nickel-iron alloy@nitrogen-containing carbon (NiFe@NC) catalyst and the beneficial effect of alloying Ni with Fe for the above reaction. The key to this synthetic strategy was thermally transforming the Ni-Fe layered double hydroxide (NiFe-LDH)/melamine mixture to form a fixed NiFe@NC nanostructure. A series of characterization results revealed the formation of NiFe alloy nanoparticles (NPs) coated with the NC overlayer. The as-fabricated NiFe@NC catalyst with a Ni/Fe atomic ratio of 3.0 exhibited superior activity for the reduction of the nitro group in o-chloronitrobenzene, with a 99.5% yield of o-chloroaniline under mild reaction conditions. The initial reaction rate over the catalyst was nearly three times that over the monometallic Ni@NC counterpart, and even one-order magnitude higher than that over pristine NiFe-LDH-derived NiFe alloy NPs. The extraordinary activity of NiFe@NC was reasonably attributed to the unique core-shell nanostructure, where both the NiFe alloy core and the NC overlayer shell could construct a significant promotional effect, being beneficial for the selective cleavage of the N-O bond. Recycling experiments indicated that the catalyst could be easily separated and recovered under an external magnetic field and experienced excellent recyclability during seventeen cycles without an obvious loss of catalytic activity. Furthermore, the present catalyst was also highly active for the chemoselective hydrogenation of other substituted nitroarenes bearing different functional groups to the corresponding anilines.
- Zhang, Yaowen,Liu, Chunling,Fan, Guoli,Yang, Lan,Li, Feng
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- Well-controlled layer-by-layer assembly of carbon dot/CdS heterojunctions for efficient visible-light-driven photocatalysis
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Fluorescent carbon dots have attracted great attention, but their application in photocatalysis has not been well explored. Herein we report a facile layer-by-layer method to fabricate uniform C dot/CdS heterojunction films via an electrophoretic and sequ
- Chai, Na-Na,Wang, Hang-Xing,Hu, Chen-Xia,Wang, Qiang,Zhang, Hao-Li
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- Robust and economic reduction protocol employing immensely stable and leach-proof magnetically separable nanocomposites
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Magnetically recoverable nanocomposites i.e. metal loaded over modified ferrite nanoparticles have been synthesized via a facile three step pathway. Modification of ferrite nanoparticles which serve as the core has been achieved using dopamine hydrogen chloride. Owing to this, introduction of terminal amine groups on the surface of ferrite nanoparticles takes place which provides binding sites for the stabilization of metal nanoparticles providing leach-proof nanocomposites. The synthesized nanocomposites have been characterized using various characterization techniques. Substantiation of the modification of the pristine magnetic ferrite nano particles has been done from the emergence of strong stretching vibration bands of N-H and O-H in the range of 3200-3400 cm-1, N-H stretching band in the range of 1630-1650 cm-1, C-C vibrations of the benzene ring in the range of 1480-1500 cm-1 and C-O stretching vibrations in the range of 1070-1100 cm-1. In the XRD patterns additional peaks corresponding to loaded metals (Cu and Ag) along with peaks corresponding to spinel ferrites have been observed confirming the successful formation of the composite. EDS patterns and FE-SEM elemental mapping confirmed the purity of the samples by displaying the absence of any impurity. Elemental mapping also confirmed the uniform binding of the loaded metals over the surface of modified ferrite nanoparticles. Catalytic efficiency of the synthesized nanocomposites has been explored for the reduction of nitroarenes. Both the Cu and Ag loaded samples exhibited excellent activity and efficient recyclability for the reduction of nitroarenes in the presence of NaBH4 as a reducing agent.
- Goyal, Ankita,Singhal, Sonal
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- Atomically Conformal Metal Laminations on Plasmonic Nanocrystals for Efficient Catalysis
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Despite the enormous application potential, methods for conformal few-atomic-layer deposition on colloidal nanocrystals (NCs) are scarce. Similar to the process of lamination, we introduce a confine and shine strategy to homogeneously modify the different surface curvatures of plasmonic NCs with ultrathin conformal layers of diverse catalytic noble metals. This self-limited epitaxial skinlike metal growth harvests the localized surface plasmon resonance to induce reduction chemistry directly on the NC surface, confined inside hollow silica. This strategy avoids any kinetic anisotropic metal deposition. Unlike the conventional thick, anisotropic, and dendritic shells, which show severe nonradiative damping, the skinlike metal lamination preserves the key plasmonic properties of the core NCs. Consequently, the plasmonic-catalytic hybrid nanoreactors can carry out a variety of organic reactions with impressive rates.
- Acharya, Anubhab,Cho, Yoon-Kyoung,Dubbu, Sateesh,Kim, Yeseul,Kumar, Amit,Kumar, Sumit,Kumari, Nitee,Kwon, Taewan,Lee, In Su,Oh, Sang Ho,Park, Junbeom,Rho, Junsuk,So, Sunae,Wang, Zhipeng
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supporting information
p. 10582 - 10589
(2021/07/26)
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- Method for synthesizing heteroatom- substituted aromatic compound from styrene compound
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The invention discloses a method for synthesizing a heteroatom-substituted aromatic compound from a styrene compound, which comprises the following steps of: mixing a styrene compound with a general formula (I) and a heteroatom-containing compound with a general formula (II), and reacting in the presence of an acid additive and an organic solvent to obtain a heteroatom-substituted compound with ageneral formula (III). According to the synthesis method disclosed by the invention, a large amount of styrene compounds are used as raw materials and react to generate aromatic amine or phenol compounds under the action of no metal catalysis; and compared with the traditional aromatic amine and phenol synthesis method, the method has the advantages of high yield, simple conditions, low waste discharge amount, no metal participation, simple reaction equipment, easiness in industrial production and the like.
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Paragraph 0205-0208
(2021/02/06)
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- In situcreation of multi-metallic species inside porous silicate materials with tunable catalytic properties
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Porous metal silicate (PMS) material PMS-11, consisting of uniformly distributed multi-metallic species inside the pores, is synthesized by using a discrete multi-metal coordination complex as the template, demonstrating high catalytic activity and selectivity in hydrogenation of halogenated nitrobenzenes by synergistically activating different reactant moleculesviaNi and Co transition metal centers, while GdIIILewis acid sites play a role in tuning the catalytic properties.
- Liu, Yang-Yang,Wu, Chuan-De,Zhan, Guo-Peng
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supporting information
p. 6185 - 6188
(2021/06/30)
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- Rhodium nanoparticles supported on 2-(aminomethyl)phenols-modified Fe3O4 spheres as a magnetically recoverable catalyst for reduction of nitroarenes and the degradation of dyes in water
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A magnetic nanostructured catalyst (Fe3O4@SiO2-Amp-Rh) modified with 2-(aminomethyl)phenols (Amp) was designed and prepared, which is used to catalyze the reduction of aromatic nitro compounds into corresponding amines and the degradation of dyes. The 2-aminomethylphenol motif plays a vital role in the immobilization of rhodium nanoparticles to offer extraordinary stability, which has been characterized by using various techniques, including transmission electron microscopy (TEM), thermal gravimetric analyzer (TGA), X-Ray Diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). A variety of nitroaromatic derivatives have been reduced to the corresponding anilines in water with up to yields of 99% within 1?h at room temperature. In addition, the catalyst system is effective in catalyzing the reduction of toxic pollutant 4-nitrophenol and the degradation of MO, MB and RhB dyes. Importantly, this catalyst Fe3O4@SiO2-Amp-Rh can be easily recovered by an external magnetic field because of the presence of magnetic core of Fe3O4, and the activity of Fe3O4@SiO2-Amp-Rh does not decrease significantly after 7 times’ recycling, which indicates that the catalyst performed high reactivity as well as stability. Graphical abstract: [Figure not available: see fulltext.]
- Chen, Tian,Chen, Zhangpei,Hu, Jianshe,Lv, Kexin,Reheman, Aikebaier,Wang, Gongshu
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- Highly efficient hydrogenation reduction of aromatic nitro compounds using MOF derivative Co-N/C catalyst
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The direct hydrogenation reduction of aromatic nitro compounds to aromatic amines with non-noble metals is an attractive area. Herein, the pyrolysis of Co(2-methylimidazole)2 metal-organic framework successfully produces a magnetic Co-N/C nanocomposite, which exhibits a porous structure with a high specific area and uniform Co nanoparticle distribution in nitrogen-doped graphite. In addition, the Co-N/C catalysts possess high cobalt content (23%) with highly active β-Co as the main existing form and high nitrogen content (3%). These interesting characteristics endow the Co-N/C nanocomposite with excellent catalytic activity for the hydrogenation reduction of nitro compounds under mild conditions. In addition, the obtained Co-N/C nanocomposites possess a broad substrate scope and good cycle stability for the reduction of halogen-substituted or carbonyl substituted phenyl nitrates. This journal is
- Dai, Yuyu,Li, Xiaoqing,Wang, Likai,Xu, Xiangsheng
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p. 22908 - 22914
(2021/12/24)
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- NaI/PPh3-Mediated Photochemical Reduction and Amination of Nitroarenes
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A mild transition-metal- and photosensitizer-free photoredox system based on the combination of NaI and PPh3 was found to enable highly selective reduction of nitroarenes. This protocol tolerates a broad range of reducible functional groups such as halogen (Cl, Br, and even I), aldehyde, ketone, carboxyl, and cyano. Moreover, the photoredox catalysis with NaI and stoichiometric PPh3 provides also an alternative entry to Cadogan-type reductive amination when o-nitrobiarenes were used.
- Qu, Zhonghua,Chen, Xing,Zhong, Shuai,Deng, Guo-Jun,Huang, Huawen
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supporting information
p. 5349 - 5353
(2021/07/21)
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- Cyclic (Alkyl)(amino)carbene Ligand-Promoted Nitro Deoxygenative Hydroboration with Chromium Catalysis: Scope, Mechanism, and Applications
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Transition metal catalysis that utilizes N-heterocyclic carbenes as noninnocent ligands in promoting transformations has not been well studied. We report here a cyclic (alkyl)(amino)carbene (CAAC) ligand-promoted nitro deoxygenative hydroboration with cost-effective chromium catalysis. Using 1 mol % of CAAC-Cr precatalyst, the addition of HBpin to nitro scaffolds leads to deoxygenation, allowing for the retention of various reducible functionalities and the compatibility of sensitive groups toward hydroboration, thereby providing a mild, chemoselective, and facile strategy to form anilines, as well as heteroaryl and aliphatic amine derivatives, with broad scope and particularly high turnover numbers (up to 1.8 × 106). Mechanistic studies, based on theoretical calculations, indicate that the CAAC ligand plays an important role in promoting polarity reversal of hydride of HBpin; it serves as an H-shuttle to facilitate deoxygenative hydroboration. The preparation of several commercially available pharmaceuticals by means of this strategy highlights its potential application in medicinal chemistry.
- Zhao, Lixing,Hu, Chenyang,Cong, Xuefeng,Deng, Gongda,Liu, Liu Leo,Luo, Meiming,Zeng, Xiaoming
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supporting information
p. 1618 - 1629
(2021/01/25)
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- A novel water-dispersible and magnetically recyclable nickel nanoparticles for the one-pot reduction-Schiff base condensation of nitroarenes in pure water
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In this work, a heterogeneous nanocatalyst called Ni-Fe3O4@Pectin~PPA ~ Piconal was first synthesized, which was investigated as a bifunctional catalyst containing nickel functional groups. On the other hand, this Ni-Fe3O4@Pectin~PPA ~ Piconal catalyst in aqueous solvents shows a very effective performance at ambient temperature for the nitroarene reduction reaction with sodium borohydride, for which NaBH4 is considered as a reducing agent. This is a novelty magnetic catalyst that was approved by various methods, including Fourier-transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), Dynamic light scattering (DLS), Transmission electron microscopy (TEM), vibrating sample magnetometer (VSM), Inductively coupled plasma (ICP), Energy-dispersive X-ray spectroscopy (EDX), and Field emission scanning electron microscopy (FESEM) analyses. From the satisfactory results obtained from the reduction of nitrogen, this catalytic system is used for a one-pot protocol containing a reduction-Schiff base concentration of diverse nitroarenes. It was corroborated with the heterogeneous catalytic experiments on the one-pot tandem synthesis of imines from nitroarenes and aldehydes. Finally, the novel Ni-Fe3O4@Pectin~PPA ~ Piconal catalyst could function as a more economically desirable and environmentally amicable in the catalysis field. The favorable products are acquired in good to high performance in the attendance of Ni-Fe3O4@Pectin~PPA ~ Piconal as a bifunctional catalyst. This catalyst can be recycled up to six steps without losing a sharp drop.
- Ghamari Kargar, Pouya,Ravanjamjah, Asiye,Bagherzade, Ghodsieh
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p. 1916 - 1933
(2021/07/10)
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- Chemoselective reduction of nitroarenes, N-acetylation of arylamines, and one-pot reductive acetylation of nitroarenes using carbon-supported palladium catalytic system in water
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Developing and/or modifying fundamental chemical reactions using chemical industry-favorite heterogeneous recoverable catalytic systems in the water solvent is very important. In this paper, we developed convenient, green, and efficient approaches for the chemoselective reduction of nitroarenes, N-acetylation of arylamines, and one-pot reductive acetylation of nitroarenes in the presence of the recoverable heterogeneous carbon-supported palladium (Pd/C) catalytic system in water. The utilize of the simple, effective, and recoverable catalyst and also using of water as an entirely green solvent along with relatively short reaction times and good-to-excellent yields of the desired products are some of the noticeable features of the presented synthetic protocols. Graphic abstract: [Figure not available: see fulltext.].
- Zeynizadeh, Behzad,Mohammad Aminzadeh, Farkhondeh,Mousavi, Hossein
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p. 3289 - 3312
(2021/05/11)
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- Magnetically‐recoverable Schiff base complex of Pd(II) immobilized on Fe3O4@SiO2 nanoparticles: an efficient catalyst for the reduction of aromatic nitro compounds to aniline derivatives
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Fe3O4@SiO2/Schiff base/Pd(II) is reported as a magnetically recoverable heterogeneous catalyst for the chemoselective reduction of aromatic nitro compounds to the corresponding amines through catalytic transfer hydrogenation (CTH). In this regard, a small amount of the nanocatalyst (0.52?mol% Pd) and hydrazine hydrate, showing safe characteristics and perfect ability as the hydrogen donor, were added to the nitro substrates. The experiments described the successful reduction of aromatic nitro compounds with good to excellent yields and short reaction times. The catalyst, due to its magnetic property, could be simply separated from the reaction mixture by a permanent magnet and reused in seven consecutive reactions without considerable loss in its activity. Moreover, the leaching of Pd was only 3.6% after the seventh run. Thus, the most striking feature of this method is to use a small amount of the magnetic nanocatalyst along with a cheap and safe hydrogen source to produce the important amine substances selectively, which makes the method economical, cheap, environmentally friendly, and simple. Graphic abstract: [Figure not available: see fulltext.]
- Azadi, Sedigheh,Esmaeilpour, Mohsen,Sardarian, Ali Reza
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p. 809 - 821
(2021/07/20)
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- Activated Mont K10-Carbon supported Fe2O3: A versatile catalyst for hydration of nitriles to amides and reduction of nitro compounds to amines in aqueous media
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The iron oxide was successfully supported on activated clay/carbon through an experimentally viable protocol for both hydrations of nitrile to amide and reduction of nitro compounds to amines. The as-prepared catalyst has been extensively characterised by XPS, SEM-EDX, TEM, TGA, BET surface area measurements and powdered X-ray diffraction (PXRD). A wide variety of substrates could be converted to the desired products with good to excellent yields by using water as a green solvent for both the reactions. The catalyst was recyclable and reusable up to six consecutive cycles without compromising its catalytic proficiency. Graphical abstract: Activated Mont K10 carbon-supported Fe2O3 is a very efficient and versatile heterogeneous catalytic system for hydration of nitriles to amides and reduction of nitro compounds to amines and can be reused up to six consecutive cycles without significant loss in catalytic activity.[Figure not available: see fulltext.].
- Rahman, Taskia,Borah, Geetika,Gogoi, Pradip K
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- Zn(0)-Catalysed mild and selective hydrogenation of nitroarenes
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The hydrogenation of nitroarenes is one of the most important strategies for the preparation of anilines. However, it is still a great challenge to develop mild and efficient synthetic routes toward aniline synthesis, particularly those employing both non-precious metal catalysts and low-pressure H2. Herein, we report a highly efficient protocol for the selective hydrogenation of nitroarenes in neutral H2O using H2 (1 atm) over a heterogeneous Zn(0) catalyst under mild conditions. The nitro groups of an array of nitroarenes can be converted into -NH2 with up to 99percent conversions and a selectivity of >99percent, even when functionalized with easily reducible substituents, or in the presence of aromatic ketones or styrene. This study might open an avenue for the selective hydrogenation of nitroarenes over a zinc catalyst using 1 atm H2.
- Du, Muyao,Hu, Pan,Jv, Xinchun,Sun, Shuting,Wang, Bo,Zhang, Qun,Zhao, Ruixiang
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supporting information
p. 4640 - 4644
(2020/08/10)
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- Tuneable Copper Catalysed Transfer Hydrogenation of Nitrobenzenes to Aniline or Azo Derivatives
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A highly versatile and flexible copper nanoparticle (Cu(0) NPs) catalytic system has been developed for the controlled and selective transfer hydrogenation of nitroarene. Interestingly, the final catalytic product is strongly dependent on the nature of the hydrogen donor source. The yield of nitrobenzene reduction to aniline increased from 20% to an almost quantitative yield over a range of alcohols, diols and aminoalcohols. In glycerol at 130 °C aniline was isolated in 93% yield. In ethanolamine, the reaction was conveniently performed at a lower temperature (55 °C) and gave selectively substituted azobenzene (92% yield). Experimental studies provide support for a reaction pathway in which the Cu(0) NPs catalysed transfer hydrogenation of nitrobenzene to aniline proceeds via the condensation route. The high chemoselectivity of both protocols has been proved in experiments on a panel of variously substituted nitroarenes. Enabling technologies, microwaves and ultrasound, used both separately and in combination, have successfully increased the reaction rate and reaction yield. (Figure presented.).
- Moran, Maria Jesus,Martina, Katia,Baricco, Francesca,Tagliapietra, Silvia,Manzoli, Maela,Cravotto, Giancarlo
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supporting information
p. 2689 - 2700
(2020/05/18)
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- Method for reducing aromatic nitro into arylamine
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The invention relates to a method for reducing aromatic nitro to arylamine. The method comprises the following steps: (1) taking an aromatic nitro compound as a raw material, water as a hydrogen source, a palladium compound, cheap and easy to obtain, as a catalyst and tetrahydroxydiboron as an additive to reduce nitro to obtain a product; (2) taking the aromatic nitro compound as the raw material, a copper salt, cheap and easy to obtain, as the catalyst, the tetrahydroxydiboron as the additive to reduce the nitro to obtain a product; and (3) taking the aromatic nitro compound as the raw material, water as the hydrogen source, and the tetrahydroxydiboron as the additive, without needing a metal catalyst, to reduce the nitro to obtain a product. A preparation method for the arylamine, which is provided by the invention, is mild in reaction condition, low in costs, environment-friendly, high in yield, and suitable for industrial production.
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Paragraph 0105-0108; 0209-0212
(2020/07/15)
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- N,S co-doped hierarchically porous carbon materials for efficient metal-free catalysis
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Metal-free carbon catalysts with excellent catalytic performance have drawn much research attention recently. Herein, polymer-derived N,S co-doped carbon catalysts (PDNSC-X) with a hierarchically porous structure were facilely prepared by a cost-effective and convenient strategy via carbonization of a N- and S atom-containing polymer precursor and were subsequently used as efficient metal-free catalysts. The catalytic activity of the as-fabricated PDNSC-800 was greater than those of other reported heteroatom-doped carbon catalysts in catalytic reduction of various nitroarenes. The high catalytic activity of PDNSC-800 was related to the synergistic effects of a high surface area, a hierarchically porous structure, abundant N- and S-containing active sites, and defect formation. In addition, the close relationship between the N species (especially pyrrolic N) and high selectivity in metal-free catalytic synthesis was investigated in the reduction of nitroarenes and selective oxidation of ethylbenzene. This study may provide a new strategy to fabricate specific heteroatom-doped metal-free carbon catalysts for environmentally friendly efficient organic transformation.
- Hu, Xiwei,Sun, Xun,Song, Qiang,Zhu, Yangyang,Long, Yu,Dong, Zhengping
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supporting information
p. 742 - 752
(2020/02/21)
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- Deacetylative Amination of Acetyl Arenes and Alkanes with C-C Bond Cleavage
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The Br?nsted acid-catalyzed synthesis of primary amines from acetyl arenes and alkanes with C-C bond cleavage is described. Although the conversion from an acetyl group to amine has traditionally required multiple steps, the method described herein, which uses an oxime reagent as an amino group source, achieves the transformation directly via domino transoximation/Beckmann rearrangement/Pinner reaction. The method was also applied to the synthesis of γ-aminobutyric acids, such as baclophen and rolipram.
- Hyodo, Kengo,Hasegawa, Genna,Maki, Hiroya,Uchida, Kingo
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supporting information
p. 2818 - 2822
(2019/04/25)
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- Hydrogenation of Functionalized Nitroarenes Catalyzed by Single-Phase Pyrite FeS2 Nanoparticles on N,S-Codoped Porous Carbon
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Catalytic hydrogenation of nitroarenes is an industrially very important and environmentally friendly process for the production of anilines; however, highly chemoselective reduction of nitroarenes decorated with one or more reducible groups in a nitroarene molecule remains a challenge. Herein, a novel hybrid non-noble iron-based nanocatalyst (named as FeS2/NSC) was developed, which was prepared from biomass as C and N source together with inexpensive Fe(NO3)3 as Fe source through high-temperature pyrolysis in a straightforward and cost-effective procedure. Comprehensive characterization revealed that single-phase pyrite FeS2 nanoparticles with precisely defined composition and uniform size were homogeneously dispersed on N,S-codoped porous carbon with large specific surface area, hierarchical porous channels, and high pore volume. The resultant catalyst FeS2/NSC demonstrated good catalytic activity for hydrogenation of functionalized nitroarenes with good tolerance of various functional groups in water as a sustainable and green solvent. Compared with bulk pyrite FeS2 and other non-noble metal-based heterogeneous catalysts reported in the literature, a remarkably enhanced activity was observed under mild reaction conditions. More importantly, FeS2/NSC displayed exclusive chemoselectivity for the reduction of nitro groups for nitroarenes bearing varying readily reducible groups.
- Duan, Yanan,Dong, Xiaosu,Song, Tao,Wang, Zhaozhan,Xiao, Jianliang,Yuan, Youzhu,Yang, Yong
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- Hydroxyl Assisted Rhodium Catalyst Supported on Goethite Nanoflower for Chemoselective Catalytic Transfer Hydrogenation of Fully Converted Nitrostyrenes
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Control of chemoselectivity is a special challenge for the reduction of nitroarenes bearing one or more unsaturated groups. Here, we report a flower-like Rh/α-FeOOH catalyst for the chemoselective hydrogenation of nitrostyrene to vinylaniline over full conversion, which benefits the new functionalized aminostyrene because the multisubstituted aminostyrenes are usually commercially unavailable. This catalyst does not only show desirable selectivity for the vinylanilines, but also exhibits the inertness to various other reducible groups over wide reaction duration. The catalytic selectivity for the reduction of the nitro group towards vinyl group was investigated by the control experiments and FT-IR analysis. We have found that the abundant hydroxyl groups in the α-FeOOH may contribute to the improvement of catalytic activity and selectivity. Furthermore, the catalyst exhibits excellent stability and keeps its catalytic performance even after 6 cycles. (Figure presented.).
- Hu, Zenan,Ai, Yongjian,Liu, Lei,Zhou, Junjie,Zhang, Gang,Liu, Hongqi,Liu, Xiangyu,Liu, Zhibo,Hu, Jianshe,Sun, Hong-bin,Liang, Qionglin
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supporting information
p. 3146 - 3154
(2019/05/10)
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- Cobalt nanoparticles anchoring on nitrogen doped carbon with excellent performances for transfer hydrogenation of nitrocompounds to primary amines and N-substituted formamides with formic acid
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Cobalt nanoparticles anchoring on nitrogen doped carbon derived from pyrolysis of a cobalt complex and chitosan were developed for reduction of nitrocompounds with neat formic acid to their corresponding amines or N-substituted formamides by switch of solvents. Characterization results revealed that most of the nitrogen atoms are present as graphitic N and pyridinic N as anchoring sites, and the cobalt nanoparticles are wrapped by nitrogen doped carbon layers, endowing the catalyst with excellent activity and superior reusability.
- Zhang, Yuecheng,Cao, Pengwei,Zhang, Hong-Yu,Yin, Guohui,Zhao, Jiquan
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- Green and convenient protocols for the efficient reduction of nitriles and nitro compounds to corresponding amines with NaBH4 in water catalyzed by magnetically retrievable CuFe2O4 nanoparticles
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Abstract: In this study, firstly, CuFe2O4 nanoparticles were prepared by a simple operation. The structure of the mentioned nanoparticles was characterized by Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, inductively coupled plasma-optical emission spectrometry, vibrating sample magnetometer and also Brunauer–Emmett–Teller and Barrett–Joyner–Halenda analyses. The prepared magnetically copper ferrite nanocomposite was successfully applied as a simple, cost-effective, practicable, and recoverable catalyst on the green, highly efficient, fast, base-free, and ligand-free reduction of nitriles and also on the affordable and eco-friendly reduction of nitro compounds with the broad substrate scope to the corresponding amines with NaBH4 in water at reflux in high to excellent yields. Graphical abstract: [Figure not available: see fulltext.].
- Zeynizadeh, Behzad,Mohammad Aminzadeh, Farkhondeh,Mousavi, Hossein
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- Bio-synthesis and structural characterization of highly stable silver nanoparticles decorated on a sustainable bio-composite for catalytic reduction of nitroarenes
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Bio-polymers are the most significant natural alternative stabilizers compared to their synthetic counterparts for fabrication of noble metal nanoparticles because of their higher thermal stability, renewability, low cost, eco-friendliness, strong mechanical capacity, and biodegradability properties. Therefore, a new bio-composite (CMC-Pct-AG), which is consisted of sodium carboxymethyl cellulose, agar, and pectin natural biopolymers, was fabricated as an immobilizing agent in this study. Then, highly stable silver nanoparticles (Ag NPs@CMC-AG-Pct) were successfully decorated on the surface of designed CMC-Pct-AG without the use of any hazardous reducing agents, and their chemical structures were illuminated with Uv–Vis, FT-IR, TG/DTG, SEM, EDS, XRD, and ICP-OES analyses. Subsequently, the catalytic performance of Ag NPs@CMC-AG-Pct was studied in the reduction of various nitroarenes in the presence of NaBH4 at room temperature. These tests indicate that Ag NPs@CMC-AG-Pct is an efficient catalyst which converts nitroarenes to desired amines with good yields and short reaction times. Reproducibility of the catalyst was also investigated, and it is found that Ag NPs@CMC-AG-Pct served several times as a retrievable and reusable catalyst for catalytic reduction of nitroarenes.
- Baran, Talat
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p. 213 - 218
(2019/02/07)
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- Metal-free chemoselective reduction of nitroaromatics to anilines via hydrogen transfer strategy
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A novel protocol for chemoselective reduction of aromatic nitro compounds to aromatic amines has been established. The metal-free reduction goes through a hydrogen transfer process. Various easily reducible functional groups can be well tolerated under the optimized reaction conditions.
- Shuai, Qi,Li, Jun,Zhao, Feng,Su, Weike,Deng, Guojun
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p. 965 - 975
(2019/04/13)
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- One-Pot Synthesis of Heterobimetallic Metal–Organic Frameworks (MOFs) for Multifunctional Catalysis
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A one-pot synthesis of bimetallic metal–organic frameworks (Co/Fe-MOFs) was achieved by treating stoichiometric amounts of Fe and Co salts with 2-aminoterephthalic acid (NH2-BDC). Monometallic Fe (catalyst A) and Co (catalyst F) were also prepared along with mixed-metal Fe/Co catalysts (B–E) by changing the Fe/Co ratio. For mixed-metal catalysts (B–E) SEM energy-dispersive X-ray (EDX) analysis confirmed the incorporation of both Fe and Co in the catalysts. However, a spindle-shaped morphology, typically known for the Fe-MIL-88B structure and confirmed by PXRD analysis, was only observed for catalysts A–D. To test the catalytic potential of mixed-metal MOFs, reduction of nitroarenes was selected as a benchmark reaction. Incorporation of Co enhanced the activity of the catalysts compared with the parent NH2-BDC-Fe catalyst. These MOFs were also tested as electrocatalysts for the oxygen evolution reaction (OER) and the best activity was exhibited by mixed-metal Fe/Co-MOF (Fe/Co batch ratio=1). The catalyst provided a current density of 10 mA cm?2 at 410 mV overpotential, which is comparable to the benchmark OER catalyst (i.e., RuO2). Moreover, it showed long-term stability in 1 m KOH. In a third catalytic test, dehydrogenation of sodium borohydride showed high activity (turnover frequency=87 min?1) and hydrogen generation rate (67 L min?1 g?1 catalyst). This is the first example of the synthesis of bimetallic MOFs as multifunctional catalysts particularly for catalytic reduction of nitroarenes and dehydrogenation reactions.
- Iqbal, Bushra,Saleem, Murtaza,Arshad, Salman Noshear,Rashid, Jamshaid,Hussain, Naveed,Zaheer, Muhammad
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p. 10490 - 10498
(2019/07/15)
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- Electronic Modulation of Palladium in Metal Phosphide Nanoparticles for Chemoselective Reduction of Halogenated Nitrobenzenes
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Tuning the electronic property of a transition metal plays an important role in the selective catalysis. Herein, the control synthesis of (PdxNiy)-P nanoparticles is reported. The binding energy of Pd3d5/2 as a function of
- Zhao, Ming,Feng, Baoming,Qiao, Xiaofei,Zhong, Ning,Ge, Xuemei,Ji, Yuan
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p. 407 - 410
(2019/01/14)
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- Reduction of Nitroarenes to Anilines with a Benzothiazoline: Application to Enantioselective Synthesis of 2-Arylquinoline Derivatives
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The metal-free reduction of nitroarenes to aniline derivatives was accomplished in a short time by using a benzothiazoline as the hydrogen donor in combination with a Bronsted acid. An enantioselective synthesis of 2-arylquinolines was achieved by using 1-aryl-3-(2-nitrophenyl)propan-1-ones as starting materials and a combination of a benzothiazoline and a chiral phosphoric acid.
- Miyagawa, Masamichi,Yamamoto, Ryota,Kobayashi, Nanako,Akiyama, Takahiko
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supporting information
p. 499 - 502
(2019/02/26)
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- Bi-functional catalyst of porous N-doped carbon with bimetallic FeCu for solvent-free resultant imines and hydrogenation of nitroarenes
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The efficient and stable catalyst applied to the transformation of amines into the corresponding imines and hydrogenation of nitroarenes under mild reaction conditions is reported. The catalytic performance of porous N-doped carbon with FeCu (FeCu@NPC) catalyst are tested by aromatic alcohol-based N-alkylated of amines with solvent-free and hydrogenation of nitroarenes via N2H4·H2O. The results proved that the yield of these two reactions are all over 99.9% under optimum condition. Moreover, the synergistic effect of the catalyst for N-alkylated reaction was investigated through the kinetic study. The catalyst can be easily separated from reaction system by an external magnetism, and can be recycled and reutilized for at least 4 runs with conversions are all over 75%. The study of the catalyst indicated that it was suitable for the reactions in industry. Hence, the catalysis process by the inexpensive metals-based catalyst is green and sustainable.
- Wang, Kaizhi,Gao, Wenbing,Jiang, Pengbo,Lan, Kai,Yang, Ming,Huang, Xiaokang,Ma, Lei,Niu, Fang,Li, Rong
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- Fe/Fe2O3@N-dopped Porous Carbon: A High-Performance Catalyst for Selective Hydrogenation of Nitro Compounds
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Herein, we designed and prepared a novel Fe/Fe2O3-based catalyst, in which a remarkable synergistic effect has been revealed between Fe and Fe2O3 encapsulated in N-doping porous carbon. The Fe-based catalysts were fabricated via pyrolysis a mixture of MIL-101(Fe) and melamine. The catalyst exhibits exceptionally high catalytic activity (TOFs up to 8898 h?1 which is about 100 times higher than the similar kinds of catalysts) and chemoselectivity for nitroarene reduction under mild conditions.
- Yun, Ruirui,Hong, Lirui,Ma, Wanjiao,Jia, Weiguo,Liu, Shoujie,Zheng, Baishu
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p. 724 - 728
(2019/01/04)
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- High Selectivity of Hydrogenation Reaction over Co0.15@C/PC Catalyst at Room Temperature
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In the field of catalysis, material scientists pay much attention to tuning the activity and chemoselectivity of metal nanoparticles. Herein, we design and successfully synthesize a series of Co NPs which show high performance on hydrogenation of nitroarenes with both activity and chemoselectivity. Co0.15@C/PC preferentially activates the -C=O bond over -NO2 in water with ammonia borane (AB); however, when the hydrogen source is changes to hydrazine hydrate (HH), the results are the opposite. The Co-based catalyst exhibits exceptionally high catalytic activity (with a TOF value of 10512 h-1, which is approximately 100 times than the akin catalysts) and chemo-selectivity for the hydrogenation of nitro compounds under mild conditions. Additionally, the catalyst can be separated easily by a magnet and shows prominent stabilit, which means that it can be reused for at least 10 cycles.
- Yun, Ruirui,Ma, Wanjiao,Wang, Suna,Jia, Weiguo,Zheng, Baishu
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- Co-MOF-Derived Hierarchical Mesoporous Yolk-shell-structured Nanoreactor for the Catalytic Reduction of Nitroarenes with Hydrazine Hydrate
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Porous nanoreactors demonstrate immense potential for applications in heterogeneous catalysis due to their excellent mass-transfer performance and stability. The design of a simple, universal strategy for fabricating nanoreactor catalysts is of significance for organic transformation. In this study, a nanoreactor with a hierarchical mesoporous yolk-shell structure was successfully prepared by the high-temperature carbonization of a ZIF-67@polymer composite. The core of the resultant Co@ZDC@mC material comprised Co NPs anchored in the ZIF-67-derived carbon framework, while the shell comprised resin-polymer-derived mesoporous carbon. The as-obtained Co@ZDC@mC-700 catalyst enriched reactants, efficiently catalyzed the reaction in the core, and permitted the desorption of the product from the nanoreactor. In the catalytic reduction of nitrobenzene with N2H4?H2O, Co@ZDC@mC-700 exhibited superior catalytic efficiency (TOF=1136.3 h?1). In addition, Co@ZDC@mC-700 exhibited excellent performance for the catalytic reduction of various functionalized nitroarenes, as well as good reusability and recyclability. Hence, a simple, useful approach for fabricating a metal-organic-framework-derived non-noble metal-based yolk-shell nanoreactor for effective catalytic transformation is proposed.
- Yuan, Man,Zhang, Hongbo,Yang, Chen,Wang, Fanhao,Dong, Zhengping
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p. 3327 - 3338
(2019/07/04)
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- One-pot photocalalytic reductive formylation of nitroarenes via multielectron transfer by carbon nitride in functional eutectic medium
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In the past years organic semiconductor photocatalysis has made the remarkable advances in developing efficient synthetic chemical routes to well refined structures. Until now, most efforts were focused on optimizing of the semiconductor photocatalyst, while solvents were largely ignored. Herein, we design a series of functional deep eutectic solvents (DES) with adjustable physicochemical properties – density, viscosity, glass transition temperature, and chemical activity towards reductive formylation of nitroarenes. The DES are prepared from abundant, sustainable resources, which makes them an affordable alternative to the ionic liquids, even on larger industrial scales. By combining the ammonium formate-based DES with carbon nitride photocatalyst, we enable the simultaneous six-electron reduction of nitro-compounds to the corresponding N-substituted formamides and benzimidazoles in one pot.
- Markushyna, Yevheniia,V?lkel, Antje,Savateev, Aleksandr,Antonietti, Markus,Filonenko, Svitlana
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p. 186 - 194
(2019/11/26)
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- Ethyl 6-Hydroxyfulvene-1-Carboxylate: A Reagent Discriminating Primary Amines from Secondary Amines
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A highly chemo-selective reaction was observed when ethyl 6-hydroxyfulvene-1-carboxylate 1 was treated with different nucleophiles such as primary amines, secondary amines, alcohols, and thiols. Among them, only primary amines are reactive toward 1 to afford the condensation products 3, which exhibit good stability under both weakly acidic and basic conditions. The condensation process proved to be reversible between different primary amines. On the basis of this observation, the chemical selectivity of typical primary aromatic amines was evaluated quantitatively by determining equilibrium constants of the condensation reactions with aniline as a reference. Moreover, the primary amines of 3 can be readily released upon treatment with aqueous ammonia, making 6-hydroxyfulvene-1-carboxylate 1 a promising protecting reagent for primary amines.
- Yang, Sen,Lu, Dengfu,Zhu, Yuequan,Shi, Mei,Luo, Fan,Gong, Yuefa
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p. 6681 - 6689
(2018/06/11)
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- Copper mediated C-H amination with oximes: En route to primary anilines
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Here we report an efficient Cu(i)-mediated C-H amination reaction with oximes as amino donors to introduce NH2 groups directly. Various strongly coordinating heterocycles including quinoline, pyrimidine, pyrazine, pyrazole and triazole were tolerated well. The potential utility was further demonstrated in a late-stage modification of telmisartan (an antagonist for the angiotensin II receptor).
- Xu, Lin-Lin,Wang, Xing,Ma, Biao,Yin, Ming-Xing,Lin, Hai-Xia,Dai, Hui-Xiong,Yu, Jin-Quan
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p. 5160 - 5164
(2018/06/21)
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- AMINATION AND HYDROXYLATION OF ARYLMETAL COMPOUNDS
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In one aspect, the present disclosure provides methods of preparing a primary or secondary amine and hydroxylated aromatic compounds. In some embodiments, the aromatic compound may be unsubstituted, substituted, or contain one or more heteroatoms within the rings of the aromatic compound. The methods described herein may be carried out without the need for transition metal catalysts or harsh reaction conditions.
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Paragraph 0098; 0136; 0137; 0210
(2018/03/25)
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- A fragrant amines for the preparation of compounds (by machine translation)
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The invention discloses a fragrant amines preparation method of the compound, the method in a certain amount of supported cobalt-containing catalyst and a certain amount of fragrant nitryl compounds added in the reactor, then adding ammonium formate, and tetrahydrofuran mixed solvent with water, under stirring, the reaction temperature is 80 - 200 °C, reaction 0.5 - 24 h, to get the corresponding sweet-smelling amines compound. According to the preparation method of this invention the use of inexpensive, renewable bamboo shoots as raw materials for preparing carbon precursor, environmental protection, simple and easy to obtain, without adding nitrogen source material; at the same time in order to triphenylphosphine as the phosphorus source, low price. The substituted ammonium hydrogen as the reducing agent, the operation is simple, mild reaction conditions, in particular to an easily reducible functional group containing fragrant nitryl compounds for chemical selectivity can be controlled more easily. (by machine translation)
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Paragraph 0041-0045
(2018/11/10)
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- The Direct Synthesis of Imines, Benzimidazoles and Quinoxalines from Nitroarenes and Carbonyl Compounds by Selective Nitroarene Hydrogenation Employing a Reusable Iron Catalyst
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The “replacement” of noble metals by earth abundant metals is a desirable aim in catalysis and a possible way of conserving rare elements. The “replacement” is especially attractive if novel selectivity patterns are observed permitting the development of novel coupling reactions. Herein, we report on a novel, robust and reusable iron catalyst, which permits the selective hydrogenation of nitroarenes in the presence of hydrogenation-sensitive functional groups. Based on the selectivity pattern observed, the direct iron-catalyzed synthesis of imines and benzimidazoles from nitroarenes and aldehydes becomes feasible. In addition, we introduce the direct synthesis of quinoxalines from nitroarenes and diketones applying our catalyst.
- B?umler, Christoph,Kempe, Rhett
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supporting information
p. 8989 - 8993
(2018/05/30)
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- Metal-free Reduction of Nitro Aromatics to Amines with B 2 (OH) 4 /H 2 O
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A metal-free reduction of nitro aromatics mediated by diboronic acid with water as both the hydrogen donor and solvent under mild conditions has been developed. A series of aromatic amines were obtained with good functional group tolerance and in good yields.
- Chen, Danyi,Zhou, Yanmei,Zhou, Haifeng,Liu, Sensheng,Liu, Qixing,Zhang, Kaili,Uozumi, Yasuhiro
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supporting information
p. 1765 - 1768
(2018/06/26)
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- Unravelling 2-aminoquinazolin-4(3: H)-one as an organocatalyst for the chemoselective reduction of nitroarenes
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A novel, mild and transition metal-free, 2-aminoquinazolin-4(3H)-one-assisted reduction of nitroarenes employing hydrazine hydrate as reducing agent and potassium carbonate as a base is reported. For the first time, the activation of hydrazine hydrate with an organocatalyst has been explored for reduction reactions. Also for the first time, 2-aminoquinazolin-4(3H)-one and its derivatives have been investigated as hydrogen bonding organocatalysts for the reduction of nitroarenes to anilines. Sensitive functional groups such as sulfonamide, carboxyl, amide and halides were well tolerated in this green methodology with scalability and high chemoselectivity.
- Thakur, Maheshwar S.,Nayal, Onkar S.,Rana, Rohit,Kumar, Manoranjan,Sharma, Sushila,Kumar, Neeraj,Maurya, Sushil K.
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supporting information
p. 1373 - 1378
(2018/02/06)
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- Cu-catalyzed reduction of azaarenes and nitroaromatics with diboronic acid as reductant
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A ligand-free copper-catalyzed reduction of azaarenes with diboronic acid as reductant in an aprotic solvent under mild conditions has been developed. Most interestingly, the nitroazaarenes could be reduced exclusively to give the corresponding amines without touching the azaarene moieties. Furthermore, the reductive amination of aromatic nitro compounds and aromatic aldehydes has also been realized. A series of hydrogenated azaarenes and secondary amines were obtained with good functional group tolerance.
- Pi, Danwei,Zhou, Haifeng,Zhou, Yanmei,Liu, Qixing,He, Renke,Shen, Guanshuo,Uozumi, Yasuhiro
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p. 2121 - 2129
(2018/03/23)
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- Enhanced catalytic performance of cobalt nanoparticles coated with a N,P-codoped carbon shell derived from biomass for transfer hydrogenation of functionalized nitroarenes
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The development of abundantly available base metal catalysts for organic transformations remains an important goal of chemical research. Herein, we report the first facile fabrication of active, inexpensive, and reusable cobalt nanoparticles (NPs) coated with a N,P-codoped carbon shell derived from naturally renewable biomass and earth-abundant, low-cost cobalt salt and PPh3. The entire process is operationally simple, straightforward, cost-effective and environmentally benign and can be used in mass production for practical application. The resultant catalysts allow for highly efficient and selective transfer hydrogenation of functionalized nitroarenes to the corresponding anilines using formic acid or ammonium formate as the hydrogen donor. Uniformly incorporated N and P into the carbon lattices exhibited synergistic effects with the encapsulated Co NPs to engineer the structure and composition of the catalyst, thereby substantially boosting the catalytic efficiency. The most active catalyst Co@NPC-800 exhibited outstanding activity and exclusive selectivity for the reduction of functionalized nitroarenes to anilines, especially those decorated with readily reducible functional groups. The catalyst demonstrated high stability and can be easily separated by using an external magnet for successive reuses without significant loss in both activity and selectivity.
- Duan, Yanan,Song, Tao,Dong, Xiaosu,Yang, Yong
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supporting information
p. 2821 - 2828
(2018/06/29)
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- Surfactant Assembly within Pickering Emulsion Droplets for Fabrication of Interior-Structured Mesoporous Carbon Microspheres
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Large-sized carbon spheres with controllable interior architecture are highly desired, but there is no method to synthesize these materials. Here, we develop a novel method to synthesize interior-structured mesoporous carbon microspheres (MCMs), based on the surfactant assembly within water droplet-confined spaces. Our approach is shown to access a library of unprecedented MCMs such as hollow MCMs, multi-chambered MCMs, bijel-structured MCMs, multi-cored MCMs, “solid” MCMs, and honeycombed MCMs. These novel structures, unattainable for the conventional bulk synthesis even at the same conditions, suggest an intriguing effect arising from the droplet-confined spaces. This synthesis method and the hitherto unfound impact of the droplet-confined spaces on the microstructural evolution open up new horizons in exploring novel materials for innovative applications.
- Liu, Dawei,Xue, Nan,Wei, Lijuan,Zhang, Ye,Qin, Zhangfeng,Li, Xuekuan,Binks, Bernard P.,Yang, Hengquan
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supporting information
p. 10899 - 10904
(2018/08/01)
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- Shape Engineering of Biomass-Derived Nanoparticles from Hollow Spheres to Bowls through Solvent-Induced Buckling
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The realization of asymmetric hollow carbonaceous nanostructures remains a great challenge, especially when biomass is chosen as the carbon resource through hydrothermal carbonization (HTC). Herein, a simple and straightforward solvent-induced buckling strategy is demonstrated for the synthesis of asymmetric spherical and bowl-like carbonaceous nanomaterials. The formation of the bowl-like morphology was attributed to the buckling of the spherical shells induced by the dissolution of the oligomers. The bowl-like particles prepared through this solvent-driven approach demonstrated a well-controlled morphology and a uniform particle size of approximately 360 nm. The obtained nanospheres and nanobowls were loaded with CoS2 nanoparticles to act as heterogeneous catalysts for the selective hydrogenation of aromatic nitro compounds. As expected, the CoS2/nanobowls catalyst showed good tolerance to a wide scope of reducible groups and afforded both high activity and selectivity in almost all the tested substrates.
- Chen, Chunhong,Li, Xuefeng,Deng, Jiang,Wang, Zhe,Wang, Yong
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p. 2540 - 2546
(2018/08/01)
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- Metallo-supramolecular polymer engineered porous carbon framework encapsulated stable ultra-small nanoparticles: A general approach to construct highly dispersed catalysts
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The development of a general approach for fabricating stable ultra-small heterogeneous nanocatalysts has been intensively pursued. However, issues related to complex synthesis processes and structural stability have restricted their investigation and application. Here we report a facile organometallic conjunction strategy for the large-scale fabrication of porous carbon framework encapsulated highly dispersed sub-3 nm ultra-small nanoparticles (USMNPs@PCF). This methodology is based on the convenient aldol condensation reaction to manufacture a metallo-supramolecular polymer precursor and then consequent annealing to form the target nanocomposite. This technique was successfully applied to the preparation of varieties of USMNPs@PCF, including Fe, Co, Ni, Mo, Ru, Rh, Pd and Pt. As a representative application, the PCF encapsulated sub-3 nm Pd nanoparticles demonstrated remarkable durability and efficiency for chemoselective hydrogenation of nitroarenes to their corresponding anilines under ambient conditions with low catalyst loading. All hydrogenation reactions can complete in 4 min with >99% conversion and >99% chemoselectivity. The turnover frequency (TOF) was up to 11:400 h-1 for p-nitrophenol. This work provides a general, scalable and economical route for the manufacture of sub-3 nm and highly dispersed nanocomposites, which can be used in many other important fields, such as electrochemistry, energy science and environmental protection.
- Ai, Yongjian,He, Mengqi,Zhang, Feng,Long, Yang,Li, Yunzheng,Han, Qiang,Ding, Mingyu,Sun, Hong-Bin,Liang, Qionglin
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p. 16680 - 16689
(2018/09/10)
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- Ultrafine FeCu Alloy Nanoparticles Magnetically Immobilized in Amine-Rich Silica Spheres for Dehalogenation-Proof Hydrogenation of Nitroarenes
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A novel core–shell structured nanocatalyst (Fe3O4@SiO2-NH2-FeCu nanoparticles) with ultrafine FeCu alloy NPs magnetically immobilized in porous silica has been fabricated. The obtained catalyst revealed excellent activity and chemoselectivity for catalyzing the hydrogenation of nitroarenes to corresponding anilines using hydrazine hydrate as the hydrogen source, and the reaction could be carried out smoothly in water, which is an environmentally friendly solvent. The FeCu alloy effectively prevented the dehalogenation of halonitroarenes, and X-ray photoelectron spectroscopy (XPS) study showed that it resulted from the electron-enrichment of Fe from Cu. A kinetics study indicated that the reaction order was about 1.5 towards 4-CNB and the apparent active energy (Ea) was 48.1 kJ mol?1, which is a relatively low value. Furthermore, the FeCu NPs are magnetically immobilized in the silica spheres (Fe3O4@SiO2), therefore the catalyst can be easily recovered by use of an external magnet and also possesses a long life time.
- Bao, Hongjie,Li, Yunong,Liu, Lei,Ai, Yongjian,Zhou, Junjie,Qi, Li,Jiang, Ruihang,Hu, Zenan,Wang, Jingting,Sun, Hongbin,Liang, Qionglin
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supporting information
p. 14418 - 14424
(2018/09/12)
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- Selective Photocatalytic Synthesis of Haloanilines from Halonitrobenzenes over Multifunctional AuPt/Monolayer Titanate Nanosheet
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Bimetallic alloy AuPt nanoclusters supported on monolayer H1.07Ti1.73O4·H2O nanosheets (AuPt/TN) jointly complete a rapid catalytic reaction toward hydrogenation of halonitrobenzene to haloaniline in methanol under ambient conditions using HCOONH4 as a hydrogen source. Especially, AuPt/TN with a Au/Pt molar ratio of 1:2 exhibits the high catalytic conversion efficiency for halonitrobenzene (>99%) with a high selectivity of haloaniline (>99%). In situ FTIR spectra suggest that the TN affords surface Br?nsted acid sites to chemisorb and activate the halonitrobenzene molecules via the surface hydrogen bond coordination. In situ ESR experiments indicate that HCOONH4 would be decomposed to H+ and a ?CO2- radical by photogenerated holes, serving as the hydrogen source and reducing species for the reduction of the -NO2 group, respectively. Experimental results reveal that atom Pt in alloy is responsible for the hydrogenation, while Au represses the dehalogenation of haloanilines. Finally, a possible synergetic mechanism is discussed. This work highlights that the multifunctional AuPt/TN catalyst with multiple active sites exerts the respective functions to cooperatively catalyze organic transformations toward desired target products.
- Song, Yujie,Wang, Huan,Wang, Zhitong,Guo, Binbin,Jing, Kaiqiang,Li, Yanjun,Wu, Ling
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p. 9656 - 9664
(2018/10/02)
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- Aminal-based Hypercrosslinked Polymer Modified with Small Palladium Nanoparticles for Efficiently Catalytic Reduction of Nitroarenes
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Fabrication of heterogeneous catalysts with excellent activity, selectivity and stability is significant for various catalytic applications. Here, we prepared a hypercrosslinked polymer (HCP) via a facile and cost-effective strategy using ferrocenecarboxaldehyde and melamine as building blocks. Then, the HCP was modified with highly dispersed ultrafine Pd nanoparticles (Pd/HCP). The obtained Pd/HCP shows excellent catalytic activity in the catalytic reduction of nitroarenes under mild reaction conditions. It′s worth mentioning that the N atoms in the HCP can efficiently coordinate Pd ions to form small Pd nanoparticles (NPs) and subsequently prevent the aggregation and leaching of Pd NPs during the reaction, so the Pd/HCP catalyst is highly stable and can be reused at least eight cycles without loss of catalytic activity. Therefore, this work may provide possibilities for using HCPs as ideal supporting materials for fabricating highly stable and efficient heterogeneous catalysts.
- Xu, Dan,Wang, Fushan,Yu, Guiqin,Zhao, Hong,Yang, Jing,Yuan, Man,Zhang, Xiaoyun,Dong, Zhengping
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p. 4569 - 4577
(2018/09/11)
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- Biomass Sucrose-Derived Cobalt@Nitrogen-Doped Carbon for Catalytic Transfer Hydrogenation of Nitroarenes with Formic Acid
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Fabrication of non-noble metal-based heterogeneous catalysts by a facile and cost-effective strategy for ecofriendly catalytic transfer hydrogenation (CTH) is of great significance for organic transformations. A cobalt@nitrogen-doped carbon (Co@NC) catalyst was prepared from renewable biomass-derived sucrose, harmless melamine, and earth-abundant Co(AcO)2 as the precursor materials by hydrothermal treatment and carbonization. Co nanoparticles (NPs) were coated with NC shells and uniformly embedded in the NC framework. The as-obtained Co@NC-600 (carbonized at 600 °C) catalyst exhibited excellent catalytic efficiency for CTH of various functionalized nitroarenes with formic acid (FA) as hydrogen donor in aqueous solution. The uniformly incorporated N atoms in the C matrix and the encapsulated Co NPs showed synergistic effects in the CTH reactions. A mechanistic analysis indicated that the protons from FA were activated by Co sites after being captured by N atoms, and then reacted with nitroarenes adsorbed on the surface of the catalysts to generate the corresponding aromatic amines. Moreover, the catalyst showed excellent durability and reusability without obvious decrease in activity even after five reaction cycles. Thus, the study reported herein provides a cost-effective, sustainable strategy for fabrication of biomass-derived non-noble metal-based catalysts for green and efficient catalytic transformations.
- Yuan, Man,Long, Yu,Yang, Jin,Hu, Xiwei,Xu, Dan,Zhu, Yangyang,Dong, Zhengping
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p. 4156 - 4165
(2018/11/01)
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- Stabilisation of gold nanoparticles by N-heterocyclic thiones
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Gold nanoparticles (Au-NPs) have been prepared using N-heterocyclic thiones (NHTs) as ligand stabilisers. These Au-NPs have been shown to be very stable, even in air, and have been characterized by a combination of several techniques (TEM, HR-TEM, STEM-HAADF, EDX, DLS, elemental analysis and 1H NMR). These nanoparticles are active in the catalytic reduction of nitroarenes to anilines.
- Moraes, Leonardo C.,Lacroix, Bertrand,Figueiredo, Rute C.,Lara, Patricia,Rojo, Javier,Conejero, Salvador
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supporting information
p. 8367 - 8371
(2017/07/12)
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