- Nickel–Ruthenium Bimetallic Species on Hydrotalcite Support: A Potential Hydrogenation Catalyst
-
Nickel–ruthenium loaded on magnesium–aluminium hydrotalcite materials were prepared by a post-synthetic method. The textural and physicochemical properties of the materials were systematically characterised by Fourier transform infra-red (FT–IR), powder X-ray diffraction (XRD), scanning electron microscope (SEM), nitrogen sorption, and X-ray photoelectron spectroscopy (XPS) analysis. The uniform distribution of bimetallic Ni-Ru on hydrotalcite support was evident from the powder XRD and HRTEM analysis of the used catalysts. The hydrogen temperature-programmed reduction profile reveals strong adsorption of hydrogen on the surface of the catalysts. The resultant materials show promising catalytic activity for nitrobenzene reduction under ambient reaction conditions. The formation of metallic nickel and ruthenium on the surface of hydrotalcite under the reaction conditions was evident through powder XRD analysis of the sample obtained under reaction condition. The reaction showed first order kinetics with respect to nitrobenzene. Furthermore, the catalytic activity remained intact for several cycles, and the catalysts also showed promising activity for the reduction of several substituted nitroarene molecules. Graphical Abstract: [Figure not available: see fulltext.].
- Ahammed, Shabas,Ganesh, V.,Ramachandran, Arya,Sakthivel, A.,Sreenavya, A.
-
-
Read Online
- Efficient and recyclable bimetallic Co–Cu catalysts for selective hydrogenation of halogenated nitroarenes
-
Silica supported N-doped carbon layers encapsulating Co–Cu nanoparticles (Co1Cux@CN/SiO2) were prepared by a one-step impregnation of Co(NO3)2·6H2O, Cu(NO3)2·3H2O, urea and glucose, following in situ carbothermal reduction. Effects of Cu contents on the catalytic performance of the Co1Cux@CN/SiO2 catalysts were investigated for selective hydrogenation of p-chloronitrobenzene to p-chloroaniline. The Co1Cu0.30@CN/SiO2 with Cu/Co molar ratio of 0.30:1 presented much higher activity and stability than the monometallic Co@CN/SiO2 catalyst. The addition of Cu into Co1Cux@CN/SiO2 catalysts had favorable effects on the formation of highly active Co–N sites and N-doped carbon layer. The role of the N-doped carbon layer was to protect the Co from oxidation by air, and the Co1Cu0.30@CN/SiO2 could be reused for at least 12 cycles without decrease in catalytic efficiency. Mechanistic and in situ infrared studies revealed that the interaction effect between the Co and Cu atoms made the surface of Co highly electron rich, which decreased adsorption of halogen groups and resulting in the enhanced selectivity during chemoselective hydrogenation of halogenated nitroarenes for a wide scope of substrates.
- Lu, Xionggang,Ren, Jiaan,Sheng, Yao,Wang, Xueguang,Wu, Baoqin,Zou, Xiujing
-
-
- In situcreation of multi-metallic species inside porous silicate materials with tunable catalytic properties
-
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
-
supporting information
p. 6185 - 6188
(2021/06/30)
-
- NaI/PPh3-Mediated Photochemical Reduction and Amination of Nitroarenes
-
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
-
supporting information
p. 5349 - 5353
(2021/07/21)
-
- A suitable modified palladium immobilized on imidazolium supported ionic liquid catalysed transfer hydrogenation of nitroarenes
-
The first well-defined modified palladium immobilized on imidazolium supported ionic liquid catalyst has been developed for the transfer hydrogenation of nitroarenes to anilines in good to excellent yields with formic acid as reducing agent. This methodology applies eco-friendly a reducing agent which is non-toxic, water soluble, more stable and simpler to handle. Particularly, the process constitutes a rare model of base-free transfer hydrogenations. The catalyst was reused up to nine consecutive cycles without any significance loss in its activity.
- Atheeswari, Alagudurai,Kanimozhi, Nallusamy,Karthikeyan, Parasuraman,Shanmugapriya, Ramasamy
-
-
- Microwave-assisted reduction of aromatic nitro compounds with novel oxo-rhenium complexes
-
The reduction of several aromatic nitro compounds to amines by means of the two novel catalytic systems ([IMes]2ReOBr3)/PhSiH3 and ([Py]3ReNOBr2)/PhSiH3 under microwave irradiation is here reported. These two systems were able to perform the reduction of nitro groups with higher TON and TOF when compared with previously reported systems based on oxo-rhenium core under standard heating, although they showed a lesser broad reaction scope compared with the known systems.
- Blacque, Olivier,Grieco, Gabriele
-
-
- Tuning acylthiourea ligands in Ru(II) catalysts for altering the reactivity and chemoselectivity of transfer hydrogenation reactions, and synthesis of 3-isopropoxy-1H-indole through a new synthetic approach
-
Ru(II)-p-cymene complexes (1–3) containing picolyl based pseudo-acylthiourea ligands (L1-L3) were synthesized and characterized. The crystallographic study confirmed the molecular structures of all the ligands (L1-L3) and complex 3. The catalytic activity of the complexes was tested mainly towards TH of carbonyl compounds and nitroarenes. The influence of steric and electronic effects of the ligands on the chemoselectivity and reactivity were reported. The catalytic activity was enhanced and chemoselectivity was switched after tuning the ligands in the catalysts, compared to their corresponding unmodified Ru(II)-p-cymene complexes. The catalysis was extended to a broad range of substrates including some challenging systems like furfural, benzoylpyridine, benzoquinone, chromanone, etc. The strategy of tuning the bifunctional ligands in the catalysts for effective and selective catalysis worked nicely. Further, the catalysis was extended to one pot synthesis of 3-isopropoxyindole from 2-nitrocinnamaldehyde, the first synthetic route similar to Baeyer Emmerling indole synthesis. All the catalytic experiments exhibited high conversion and selectivity.
- Sathishkumar, Pushpanathan N.,Prabha, Padinhattath Sachind,Bhuvanesh, Nattamai S.P.,Karvembu, Ramasamy
-
-
- In situ-formed cobalt embedded into N-doped carbon as highly efficient and selective catalysts for the hydrogenation of halogenated nitrobenzenes under mild conditions
-
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
-
-
- Direct Hydrogenation of Nitroaromatics at Room Temperature Catalyzed by Magnetically Recoverable Cu@Fe2O3 Nanoparticles
-
Metal embedded in metal oxide nanoparticles are active as catalyst in plethora of industrially important reactions. Herein, embedded Cu@Fe2O3 nanoparticles was synthesized via a one step hydrothermal strategy which selectively catalyzes the hydrogenation of diverse nitroaromatics in H2O at room temperature. The remarkable catalytic performance is due to the successful hybridization of metallic Cu and Fe2O3 which in turn allows easy electroflipping between various oxidation states of Cu and Fe. Azo- and azoxy-compounds are not formed during the catalyzed process. This evidently establish that the hydrogenation of nitroaromatics proceeds via direct route with >99percent selectivity to the corresponding anilines.
- Borah, Biraj Jyoti,Bharali, Pankaj
-
-
- In Situ Synthesized Silica-Supported Co@N-Doped Carbon as Highly Efficient and Reusable Catalysts for Selective Reduction of Halogenated Nitroaromatics
-
Silica-supported Co@N-doped carbon (Co@CN/SiO2) catalysts were first prepared by a one-step impregnation with a mixed solution of cobalt nitrate, glucose and urea, followed by in situ carbonization and reduction. The Co@CN/SiO2 catalysts were investigated for the selective reduction of nitro aromatics to the corresponding anilines using hydrazine hydrate. The Co@CN/SiO2-500 carbonized at 500 °C exhibited the highest catalytic activity and excellent stability without any decay of activity after 6 cycles for the reduction of nitrobenzene. Both metallic Co atoms and Co?N species formed in the Co@CN/SiO2 catalysts were active, but the Co?N species were dominant active sites. The high activities of the Co@CN/SiO2 catalysts were attributed to the synergistic effect between the Co and N atoms, promoting heterolytic cleavage of hydrazine to form H+/H? pairs. Representative examples demonstrated that the Co@CN/SiO2-500 could completely transform various halogen-substituted nitro aromatics to the corresponding halogenated anilines with high TOFs and selectivity of '99.5 percent.
- Sheng, Yao,Wang, Xueguang,Yue, Shengnan,Cheng, Gonglin,Zou, Xiujing,Lu, Xionggang
-
p. 4632 - 4641
(2020/07/30)
-
- Bio-synthesis and structural characterization of highly stable silver nanoparticles decorated on a sustainable bio-composite for catalytic reduction of nitroarenes
-
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
-
p. 213 - 218
(2019/02/07)
-
- Photocatalytic hydrogenation of nitroarenes: supporting effect of CoOx on TiO2 nanoparticles
-
Cobalt oxide visible light-active photo-catalysts supported on TiO2 nanoparticles with varying amount of cobalt oxide [3% CoOx/TiO2 (A), 4% CoOx/TiO2 (B), 5% CoOx/TiO2 (C)] were synthesized by solid-state method followed by calcination. The as-synthesized catalysts were characterized by various techniques such as powder XRD, TEM, EDX, UV-Vis-DRS and XPS analysis. The photocatalytic activity of the as-synthesized materials was studied for the reduction of nitroarenes to the corresponding amines using hydrazine monohydrate as the reductant. Cobalt(ii) oxide is responsible for the reduction of nitroarenes and then, cobalt(iii) is reduced back to the original compound by hydrazine hydrate, thus ascertaining the catalytic nature of this hydrogenation process. XPS suggests the presence of Co(ii) in CoOx/TiO2.
- Amanchi, Srinivasa Rao,Ashok Kumar,Lakshminarayana, Bhairi,Satyanarayana,Subrahmanyam
-
p. 748 - 754
(2019/01/10)
-
- Metal-free chemoselective reduction of nitroaromatics to anilines via hydrogen transfer strategy
-
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
-
p. 965 - 975
(2019/04/13)
-
- Cobalt in N-doped carbon matrix catalyst for chemoselective hydrogenation of nitroarenes
-
Anilines as important intermediates for both organic synthesis and industrial manufactory are densely substituted with a variety of functional moieties, and the transformation of nitroarenes into corresponding anilines requires catalytically selective hydrogenation catalyst. Herein, we describe a simple pyrolysis strategy to prepare cobalt catalysts in nitrogen-doped carbon matrix applied in the selective hydrogenation of nitroarenes with molecular hydrogen. The Co/NC catalysts are obtained through thermal treatment of mixed precursors of cobalt phthalocyanine and melamine. The surface-modified Co particles with Co3O4 and CoNx sites are surrounded by N-doped carbon layers according to a series of structural characterization results. These Co/NC catalysts are capable of efficiently selective hydrogenation of nitrobenzene and various substituted nitroarenes into corresponding anilines under relatively mild reaction conditions. The optimal catalytic hydrogenation performance is contributed to the fast rate of H2 dissociated activation on the CoNx active sites and the facile adsorption of the reactant substances, which is verified by the isotopic H2-D2 exchange experiments, reactant adsorption and the ORR reaction tests. Furthermore, the heterogeneous Co/NC catalyst is highly stable without the Co leaching and deactivation issues during the recycling reaction runs.
- Dai, Yihu,Jiang, Chunyang,Xu, Min,Bian, Bo,Lu, Di,Yang, Yanhui
-
p. 158 - 166
(2019/06/03)
-
- Co-MOF-Derived Hierarchical Mesoporous Yolk-shell-structured Nanoreactor for the Catalytic Reduction of Nitroarenes with Hydrazine Hydrate
-
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
-
p. 3327 - 3338
(2019/07/04)
-
- MOF-Derived Cobalt Phosphide/Carbon Nanocubes for Selective Hydrogenation of Nitroarenes to Anilines
-
Transition-metal phosphides have received tremendous attention during the past few years because they are earth-abundant, cost-effective, and show outstanding catalytic performance in several electrochemically driven conversions including hydrogen evolution, oxygen evolution, and water splitting. As one member of the transition-metal phosphides, CoxP-based materials have been widely explored as electrocatalyts; however, their application in the traditional thermal catalysis are rarely reported. In this work, cobalt phosphide/carbon nanocubes are designed and their catalytic activity for the selective hydrogenation of nitroarenes to anilines is studied. A high surface area metal-organic framework (MOF), ZIF-67, is infused with red phosphorous, and then pyrolysis promotes the facile production of the phosphide-based catalysts. The resulting composite, consisting of Co2P/CNx nanocubes, is shown to exhibit excellent catalytic performance in the selective hydrogenation of nitroarenes to anilines. To the best of our knowledge, this is the first report showing catalytic activity of a cobalt phosphide in nitroarenes hydrogenation.
- Yang, Shuliang,Peng, Li,Oveisi, Emad,Bulut, Safak,Sun, Daniel T.,Asgari, Mehrdad,Trukhina, Olga,Queen, Wendy L.
-
supporting information
p. 4234 - 4238
(2018/03/30)
-
- Metal–Organic-Framework-Derived Co3S4 Hollow Nanoboxes for the Selective Reduction of Nitroarenes
-
MOF-derived Co3S4/CN hollow nanoboxes (CN=nitrogen-doped carbon) was used to catalyze the chemoselective reduction of nitroarenes to anilines under mild reaction conditions with H2 as the reducing agent. The catalyst provides high conversion efficiencies and selectivities for a variety of nitroarene substrates that contain electron-donating or electron-withdrawing substituents under mild reaction conditions (in methanol at 60 °C). Further, the nanobox inhibits both dehalogenation and vinyl hydrogenation reactions, which are common limitations of state-of-the-art Pd-based catalysts. Because the reactions result in pure aniline products, the need for separation by column chromatography is eliminated. The resulting anilines are easily separated from the methanolic reaction solution in just three simple steps (centrifugation, decantation, and drying). If employed in industrial processes, catalysts of this kind would significantly reduce the amount of waste organic solvent generated and thus satisfy the need for sustainable chemical processes.
- Yang, Shuliang,Peng, Li,Sun, Daniel T.,Oveisi, Emad,Bulut, Safak,Queen, Wendy L.
-
p. 3131 - 3138
(2018/09/06)
-
- Selective Photocatalytic Synthesis of Haloanilines from Halonitrobenzenes over Multifunctional AuPt/Monolayer Titanate Nanosheet
-
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
-
p. 9656 - 9664
(2018/10/02)
-
- Highly efficient and durable platinum nanocatalysts stabilized by thiol-terminated poly(N-isopropyl acrylomide) for selective hydrogenation of halonitrobenzene to haloaniline
-
In this paper, the selective hydrogenation of halonitrobenzenes (HNBs) to haloanilines (HANs) under mild conditions catalyzed by well-dispersed Pt nanoparticles protected by thiol-terminated poly(N-isopropyl acrylomide) (PNIPAM-SH) was firstly investigated. The polymer not only protected the Pt nanoparticles, but also inhibited the highly active Pt catalyst from producing undesired hydrodehalogenation products through anchoring the thiol groups to the surface of Pt nanoparticles. Thus high selectivities to HANs were achieved over this modified Pt catalyst for a variety of HNBs with satisfactory catalytic activities. Especially, the selectivity to HANs showed no obvious loss with the prolonging of the reaction time. Moreover, the recycling experiment showed that this Pt nanocatalyst was easier to recover and reuse based on the cononsolvency of PNIPAM-SH. Excellent stability and reusability were presented over this catalyst, and both the catalytic activity and selectivity were well maintained after fourteen runs.
- Yu, Wenjun,Lou, Lan-Lan,Li, Shanshan,Ma, Tianyuan,Ouyang, Lezi,Feng, Li,Liu, Shuangxi
-
p. 751 - 757
(2017/01/12)
-
- A Pd@Zeolite Catalyst for Nitroarene Hydrogenation with High Product Selectivity by Sterically Controlled Adsorption in the Zeolite Micropores
-
The adsorption of molecules on metal nanoparticles can be sterically controlled through the use of zeolite crystals, which enhances the product selectivity in hydrogenations of reactants with more than one reducible group. Key to this success was the fixation of Pd nanoparticles inside Beta zeolite crystals to form a defined structure (Pd@Beta). In the hydrogenation of substituted nitroarenes with multiple reducible groups as a model reaction, the Pd@Beta catalyst exhibited superior selectivity for hydrogenation of the nitro group, outperforming both conventional Pd nanoparticles supported on zeolite crystals and a commercial Pd/C catalyst. The extraordinary selectivity of Pd@Beta was attributed to the sterically selective adsorption of the nitroarenes on the Pd nanoparticles controlled by the zeolite micropores, as elucidated by competitive adsorption and adsorbate displacement tests. Importantly, this strategy is general and was extended to the synthesis of selective Pt and Ru catalysts by fixation inside Beta and mordenite zeolites.
- Zhang, Jian,Wang, Liang,Shao, Yi,Wang, Yanqin,Gates, Bruce C.,Xiao, Feng-Shou
-
supporting information
p. 9747 - 9751
(2017/08/08)
-
- Catalytic application of 1,3,5-triazine-pentaethylenehexamine polymer-supported palladium nanoparticles in the convenient reduction of nitroarenes with sodium borohydride or hydrazine
-
The catalytic activity of 1,3,5-triazine-pentaethylenehexamine (TAPEHA) polymer-supported Pd nanoparticles was investigated in the reduction of nitro arenes to the corresponding amines by NaBH4 or N2H4 .H2 O. Optimized reaction conditions for both systems were successfully tested on 20 nitroarenes with different characteristics. Considerably high yields (80%-98% in NaBH4 and 85%-98% in N2H4) were obtained in a short time and at ambient temperature. In addition to these methods being selective against other reducible functionalities such as -CN, -Br, -Cl, and -I, the catalyst can be recovered easily and reused more than ten times.
- Gen?, Hayriye,Zengin, Mustafa,Kü?ükislamo?lu, Mustafa,Imamoglu, Mustafa,Toplan, Hüseyin ?zkan,Arslan, Mustafa
-
p. 784 - 792
(2017/11/20)
-
- Chemoselective Hydrogenation of Nitroarenes Catalyzed by Molybdenum Sulphide Clusters
-
Herein, we describe an atom efficient and general protocol for the chemoselective hydrogenation of nitroarenes to anilines catalyzed by well-defined diimino and diamino cubane-type Mo3S4 clusters. The novel diimino [Mo3S4Cl3(dnbpy)3]+ ([5]+) (dnbpy=4,4′-dinonyl-2,2′-dipyridyl, L1) trinuclear complex was synthesized in high yields by simple ligand substitution reactions starting from the thiourea (tu) [Mo3S4(tu)8(H2O)]Cl4?4 H2O (3) precursor. This strategy has also been successfully adapted for the isolation of the diamino [Mo3S4Cl3(dmen)3](BF4) ([6](BF4)), (dmen=N,N′-dimethylethylenediamine) salt. Applying these catalysts, high selectivity in the hydrogenation of functionalized nitroarenes has been accomplished. Over thirty anilines bearing synthetically functional groups have been synthesized in 70 to 99 % yield. Notably, the integrity of the cluster core is preserved during catalysis. Based on kinetic studies on the hydrogenation of nitrobenzene and other potential reaction intermediates, the direct reduction to aniline is the preferential route.
- Pedrajas, Elena,Sorribes, Iván,Gushchin, Artem L.,Laricheva, Yuliya A.,Junge, Kathrin,Beller, Matthias,Llusar, Rosa
-
p. 1128 - 1134
(2017/03/27)
-
- Co-based heterogeneous catalysts from well-defined Α-diimine complexes: Discussing the role of nitrogen
-
Ar-BIANs and related α-diimine Co complexes were wet impregnated onto Vulcan XC 72 R carbon black powder and used as precursors for the synthesis of heterogeneous supported nanoscale catalysts by pyrolysis under argon at 800?°C. The catalytic materials feature a core-shell structure composed of metallic Co and Co oxides decorated with nitrogen-doped graphitic layers (NGr). These catalysts display high activity in the liquid phase hydrogenation of aromatic nitro compounds (110?°C, 50 bar H2) to give chemoselectively substituted aryl amines. The catalytic activity is closely related to the amount and type of nitrogen atoms in the final catalytic material, which suggests a heterolytic activation of dihydrogen.
- Formenti, Dario,Ferretti, Francesco,Topf, Christoph,Surkus, Annette-Enrica,Pohl, Marga-Martina,Radnik, J?rg,Schneider, Matthias,Junge, Kathrin,Beller, Matthias,Ragaini, Fabio
-
-
- Metal–Organic Framework Mediated Cobalt/Nitrogen-Doped Carbon Hybrids as Efficient and Chemoselective Catalysts for the Hydrogenation of Nitroarenes
-
A Co@N-doped carbon (Co@NC) hybrid was synthesized by thermal decomposition of the metal–organic framework (MOF) ZIF-67 under N2 atmosphere. These hybrid materials exhibit outstanding catalytic activity and chemoselectivity for the conversion of a wide range of substituted nitroarenes to their corresponding anilines under relatively mild reaction conditions. The high catalytic performance is attributed to the formation of cobalt nanoparticles and to the presence of atomically dispersed Co species in close interaction with nitrogen-doped graphene. Both active species are formed in situ during the pyrolytic transformation of ZIF-67. The catalysts could be reused in consecutive runs, exhibiting a slightly lower activity ascribed to blockage of the active sites by strongly adsorbed reaction species. These results open up a pathway for the design of noble-metal-free solid catalysts for industrial applications.
- Sun, Xiaohui,Olivos-Suarez, Alma I.,Oar-Arteta, Lide,Rozhko, Elena,Osadchii, Dmitrii,Bavykina, Anastasiya,Kapteijn, Freek,Gascon, Jorge
-
p. 1854 - 1862
(2017/05/29)
-
- An abnormal N-heterocyclic carbene based nickel complex for catalytic reduction of nitroarenes
-
Herein we report the synthesis of a nickel(ii) dichloro complex bearing an abnormal N-heterocyclic carbene (aNHC). The NiCl2(aNHC)2 complex has been used as an efficient catalyst for the reduction of nitroarenes with hydrosilanes to give aromatic amines in good to excellent yields. This catalytic protocol can tolerate functional groups such as halides, alkenes or nitriles. Furthermore, the longevity of the catalyst was tested in successive catalytic cycles, which indicates a sustained catalytic activity over multiple catalytic cycles.
- Vijaykumar, Gonela,Mandal, Swadhin K.
-
p. 7421 - 7426
(2016/06/01)
-
- Metal-Free Reduction of Aromatic Nitro Compounds to Aromatic Amines with B2pin2 in Isopropanol
-
A metal-free reduction of aromatic nitro compounds to the corresponding amines has been achieved by a combination of B2pin2 and KOtBu in isopropanol. A series of nitro compounds containing various reducible functional groups were chemoselectively reduced in good to excellent yields.
- Lu, Hongtao,Geng, Zhiyue,Li, Jingya,Zou, Dapeng,Wu, Yusheng,Wu, Yangjie
-
supporting information
p. 2774 - 2776
(2016/06/15)
-
- Base-Free Transfer Hydrogenation of Nitroarenes Catalyzed by Micro-Mesoporous Iron Oxide
-
An efficient and practical protocol for the transfer hydrogenation of nitroarenes was developed, which uses flower-shaped micro-mesoporous iron oxide (MMIO) with formic acid as the reducing agent and tris[(2-diphenylphosphino)-ethyl]phosphine as the ligand in the absence of an additional base. The recyclable catalytic system enables the reduction of the nitro group in a broad range of substrates to yield valuable amines and shows a high tolerance to sensitive functional groups.
- Datta, Kasibhatta J.,Rathi, Anuj K.,Gawande, Manoj B.,Ranc, Vaclav,Zoppellaro, Giorgio,Varma, Rajender S.,Zboril, Radek
-
p. 2351 - 2355
(2016/07/28)
-
- Efficient Catalytic System for Chemoselective Hydrogenation of Halonitrobenzene to Haloaniline Using PtZn Intermetallic Compound
-
Nanoparticulate intermetallic PtZn acts as a highly efficient heterogeneous catalyst for chemoselective hydrogenation of halonitrobenzenes to haloanilines. Chloroanilines, bromoanilines, and iodoanilines, including all regioisomers, were obtained with excellent yields (typically >99%) under 1 atm H2 at 40°C. A gram-scale reaction afforded a turnover number (TON) of 8600. PtZn/SiO2 could be reused at least four times without significant loss of catalytic performance. PtZn/SiO2 afforded 7-fold higher TOF than Pt/SiO2. A combination of kinetic analysis, X-ray photoelectron spectroscopy (XPS) studies, and density functional theory (DFT) calculations revealed that electron-enriched Pt by Zn not only promotes nitro-hydrogenation but also effectively inhibits the carbon-halogen bond scission.
- Iihama, Sho,Furukawa, Shinya,Komatsu, Takayuki
-
p. 742 - 746
(2016/02/18)
-
- Non-noble metal catalysts for hydrogenation: A facile method for preparing Co nanoparticles covered with thin layered carbon
-
Metallic cobalt nanoparticles with surface CoOx patches covered by thin layered carbon (named Co@C) have been directly synthesized by thermal decomposition of Co-EDTA complex. Raman spectra and HRTEM images suggest that discontinuities can be found in the disordered layered carbon. XPS shows that the CoOx patches in the Co@C nanoparticles can reduced to metallic Co by H2 under reaction conditions (7 bar at 120 °C), and H2-D2 exchange experiments show that the reduced metallic Co nanoparticles covered by carbon layers can dissociate H2. The Co@C nanoparticles show excellent activity and selectivity during chemoselective hydrogenation of nitroarenes for a wide scope of substrates under mild reaction conditions. Based on the results from DRIFTS adsorption experiments, we propose that metallic Co in the Co@C nanoparticles is the active phase. The role of the carbon layers is to protect the Co from overoxidation by air, leading to the chemoselective hydrogenation of nitroarenes.
- Liu, Lichen,Concepción, Patricia,Corma, Avelino
-
-
- A highly active non-precious metal catalyst based on Fe-N-C@CNTs for nitroarene reduction
-
Research on transition metal-nitrogen-carbon (M-N-C) materials revealed their potential as catalysts in several important traditional reactions. However, the activity of M-N-C still needs to be further improved and the real active center of M-N-C catalysts is still under debate. In this work, an efficient Fe-N-C@CNTs for the hydrogenation of nitroarenes was prepared by pyrolysis of FeCl3, phenanthroline and CNTs. Fe-N-C supported on CNTs is much more active than that supported on activated carbon, showing the promotion effect of CNTs. The characterization results suggest that the high activity of Fe-N-C is mainly attributed to the formation of ?-Fe3N, which is the active site for the hydrogenation reaction. Nitrogen/carbon atoms contacted to the active centers could serve as bridges to transport the dissociated hydrogen atoms via spillover effect. The catalytic performance of Fe-N-C was also tested on fixed bed reactor under continuous flow condition for the first time and could smoothly catalyze the reaction for over 300 hours.
- Chen, Jian,Yao, Yi,Zhao, Jiao,Zhao, Yaopeng,Zheng, Yuanyuan,Li, Mingrun,Yang, Qihua
-
p. 96203 - 96209
(2016/10/22)
-
- Reduction of nitroarenes using CO and H2O in the presence of a nanostructured cobalt oxide/Nitrogen-Doped Graphene (NGr) catalyst
-
The most common route to anilines is based on the reduction of the corresponding nitroarenes. In general, hydrogen is preferred as reducing agent and numerous catalytic systems are known to achieve such transformations. Besides, the use of CO/H2O as hydrogen source offers interesting possibilities for reductions. Carbon monoxide is a cheap and abundant chemical used on industrial scale for a variety of transformations. Although the reduction of nitroarenes with CO/H2O is known in the presence of noble-metal catalysts, earth-abundant inexpensive catalysts showing high selectivity have not yet been developed. In this respect, herein we present the use of a heterogeneous cobalt oxide catalyst (Co3O4/NGr@C), which is modified by nitrogen-doped graphene layers. Using this non-noble metal catalyst nitroarenes are reduced in high yields and good chemoselectivities.
- Westerhaus, Felix A.,Sorribes, Ivn,Wienh?fer, Gerrit,Junge, Kathrin,Beller, Matthias
-
supporting information
p. 313 - 317
(2015/03/05)
-
- Synthesis of a yolk/shell Fe3O4@poly(ionic liquid)s-derived nitrogen doped graphitic porous carbon materials and its application as support for nickel catalysts
-
The synthesis of yolk/shell spheres including a movable magnetic core, a poly(ionic liquid)s-derived porous carbon shell, and nickel nanoparticles confined within the porous shell is reported. The as-prepared carbon shell is graphitic and porous, as proven by X-ray diffraction, Brunauer-Emmett-Teller equation, and transmission electron microscopy characterizations. The ensuing catalyst has been employed for the tandem dehydrogenation of sodium borohydride and hydrogenation of several nitro/nitrile compounds in aqueous media, which resulted in high yields with a very low amount of the catalyst.
- Nabid, Mohammad Reza,Bide, Yasamin,Habibi, Zahra
-
p. 2258 - 2265
(2015/02/02)
-
- Efficient reductions of various nitroarenes with scrap automobile catalyst and NaBH4
-
The effect of scrap automobile catalyst (SAC), a waste material, was investigated as a catalyst for the reduction of nitroarenes to the corresponding amines with sodium borohydride in aqueous ethanol at 5-25 °C. Along with the observed high conversions, the SAC and NaBH4 combination also exhibits a selectively catalyzed reduction in compounds containing other reducible functionalities, such as CN, Br, Cl and I. Recycling automobile wastes into a catalyst for organic reactions will offer both environmental protection and economic advantages. As a result, an effective, easy to use, low-priced and reliable method has been developed.
- Genc, Hayriye
-
-
- Highly selective transfer hydrogenation of functionalised nitroarenes using cobalt-based nanocatalysts
-
Anilines are important feedstock for the synthesis of a variety of chemicals such as dyes, pigments, pharmaceuticals and agrochemicals. The chemoselective catalytic reduction of nitro compounds represents the most important and prevalent process for the manufacture of functionalized anilines. Consequently, the development of selective catalysts for the reduction of nitro compounds in the presence of other reducible groups is a major challenge and is crucial. In this regard, herein we show that the cobalt oxide (Co3O4-NGr@C) based nano-materials, prepared by the pyrolysis of cobalt-phenanthroline complexes on carbon constitute highly selective catalysts for the transfer hydrogenation of nitroarenes to anilines using formic acid as a hydrogen source. Applying these catalysts, a series of structurally diverse and functionalized nitroarenes have been reduced to anilines with unprecedented chemo-selectivity tolerating halides, olefins, aldehyde, ketone, ester, amide and nitrile functionalities.
- Jagadeesh, Rajenahally V.,Banerjee, Debasis,Arockiam, Percia Beatrice,Junge, Henrik,Junge, Kathrin,Pohl, Marga-Martina,Radnik, J?rg,Brückner, Angelika,Beller, Matthias
-
supporting information
p. 898 - 902
(2015/03/04)
-
- Nitrogen-doped graphene-activated iron-oxide-based nanocatalysts for selective transfer hydrogenation of nitroarenes
-
Nanoscaled iron oxides on carbon were modified with nitrogen-doped graphene (NGr) and found to be excellent catalysts for the chemoselective transfer hydrogenation of nitroarenes to anilines. Under standard reaction conditions, a variety of functionalized and structurally diverse anilines, which serve as key building blocks and central intermediates for fine and bulk chemicals, were synthesized in good to excellent yields.
- Jagadeesh, Rajenahally V.,Natte, Kishore,Junge, Henrik,Beller, Matthias
-
p. 1526 - 1529
(2015/03/14)
-
- In Situ-Generated Co0-Co3O4/N-Doped Carbon Nanotubes Hybrids as Efficient and Chemoselective Catalysts for Hydrogenation of Nitroarenes
-
The earth-abundant nanohybrids Co0/Co3O4@N-doped carbon nanotubes were fabricated via an efficient thermal condensation of d-glucosamine hydrochloride, melamine, and Co(NO3)2·6H2O. The hybrids furnish excellent catalytic activity and perfect chemoselectivity (>99%) for a wide range of substituted nitroarenes (21 examples) under relatively mild conditions. The high catalytic performance and durability is attributed to the synergistic effects between each component, the unique structure of graphene layers-coated Co0, and the electronic activation of doped nitrogen. Density functional calculations indicate that the inner Co0 core and N species on the carbon shell can significantly decrease the dissociation energies of H2, giving evidence of the ability of carbon shell in the hybrids to enable H2 activation. These results open up an avenue to design more powerful low-cost catalysts for industrial applications.
- Wei, Zhongzhe,Wang, Jing,Mao, Shanjun,Su, Diefeng,Jin, Haiyan,Wang, Yihe,Xu, Fan,Li, Haoran,Wang, Yong
-
p. 4783 - 4789
(2015/08/18)
-
- Trinuclear {Co2+-M3+-Co2+} complexes catalyze reduction of nitro compounds
-
This work presents synthesis and characterization of trinuclear {Co2+-Co3+-Co2+} and {Co2+-Fe3+-Co2+} complexes with accessible peripheral Co(ii) ions. Both trinuclear complexes function as efficient reusable heterogeneous catalysts for the selective reduction of assorted nitro compounds to the corresponding amines. The mechanistic investigations suggest the involvement of a Co(ii)-Co(i) cycle in the catalysis.
- Srivastava, Sumit,Dagur, Manvender S.,Ali, Afsar,Gupta, Rajeev
-
p. 17453 - 17461
(2015/10/19)
-
- Sodium hydroxide-catalyzed transfer hydrogenation of carbonyl compounds and nitroarenes using ethanol or isopropanol as both solvent and hydrogen donor
-
The development of a clean and renewable energy carrier has become a subject of high priority, and new catalytic system that involves both abundant and cheap catalysts and green solvents is highly desirable in terms of practical and sustainable chemistry. In this spirit, sodium hydroxide-catalyzed transfer hydrogenation of carbonyl compounds using ethanol as both hydrogen source and solvent is developed in this report. The process is successfully utilized in the hydrogenation of various ketones and aldehydes, and the corresponding primary and secondary alcohols are synthesized with excellent conversions. Furthermore, sodium hydroxide also smoothly promotes the transfer hydrogenation of nitroarenes providing anilines and azobenzenes. For both carbonyl compounds and nitroarenes, results in ethanol and isopropanol are compared, and a remarkable change of selectivity between these two solvents is disclosed for the NaOH-catalyzed transfer hydrogenation to nitroarenes.
- Wang, Dong,Deraedt, Christophe,Ruiz, Jaime,Astruc, Didier
-
-
- One-pot synthesis of aluminum oxyhydroxide matrix-entrapped Pt nanoparticles as an excellent catalyst for the hydrogenation of nitrobenzene
-
Aluminum oxyhydroxide matrix-entrapped Pt nanoparticles (Pt/AlO(OH)) were synthesized via a one-pot procedure, by the reduction of Pt4+ followed by the hydrolysis of Al(O-sec-Bu)3. Small and well-dispersed Pt nanoparticles were entrapped into an aluminum oxyhydroxide matrix and confirmed by TEM characterization. FTIR analysis indicated that the Pt/AlO(OH) catalyst had a large amount of surface hydroxyl groups, which potentially improves its dispersibilty in aqueous solution. The as-prepared catalyst was used for the hydrogenation of nitrobenzene to aniline at 30 °C and atmospheric hydrogen pressure. Compared with other alcohol-water media, the hydrogenation reaction in a methanol-water medium exhibited a maximum turnover frequency (TOF) of 3620 h-1. A complete conversion of nitrobenzene with a selectivity of 99.0% was obtained with an increase of time to 150 min.
- Fan, Guangyin,Wang, Yinhu,Wang, Chenyu
-
p. 10997 - 11002
(2014/03/21)
-
- Room-temperature chemoselective reduction of nitro groups using non-noble metal nanocatalysts in water
-
Purely aqueous-phase chemoselective reduction of a wide range of aromatic and aliphatic nitro substrates has been performed in the presence of inexpensive Ni- and Co-based nanoparticle catalysts using hydrazine hydrate as a reducing agent at room temperature. Along with the observed high conversions and selectivities, the studied nanoparticle catalysts also exhibit a high tolerance to other highly reducible groups present in the nitro substrates. The development of these potential chemoselective reduction catalysts also provides a facile route for the synthesis of other industrially important fine chemicals or biologically important compounds, where other highly reducible groups are present in close proximity to the targeted nitro groups.
- Rai, Rohit K.,Mahata, Arup,Mukhopadhyay, Sushobhan,Gupta, Sampa,Li, Pei-Zhou,Nguyen, Kim T.,Zhao, Yanli,Pathak, Biswarup,Singh, Sanjay K.
-
p. 2904 - 2909
(2014/04/03)
-
- Heterogenized cobalt oxide catalysts for nitroarene reduction by pyrolysis of molecularly defined complexes
-
Molecularly well-defined homogeneous catalysts are known for a wide variety of chemical transformations. The effect of small changes in molecular structure can be studied in detail and used to optimize many processes. However, many industrial processes require heterogeneous catalysts because of their stability, ease of separation and recyclability, but these are more difficult to control on a molecular level. Here, we describe the conversion of homogeneous cobalt complexes into heterogeneous cobalt oxide catalysts via immobilization and pyrolysis on activated carbon. The catalysts thus produced are useful for the industrially important reduction of nitroarenes to anilines. The ligand indirectly controls the selectivity and activity of the recyclable catalyst and catalyst optimization can be performed at the level of the solution-phase precursor before conversion into the active heterogeneous catalyst.
- Westerhaus, Felix A.,Jagadeesh, Rajenahally V.,Wienhoefer, Gerrit,Pohl, Marga-Martina,Radnik, Joerg,Surkus, Annette-Enrica,Rabeah, Jabor,Junge, Kathrin,Junge, Henrik,Nielsen, Martin,Brueckner, Angelika,Beller, Matthias
-
p. 537 - 543
(2013/07/19)
-
- Transition metal based ionic liquid (bulk and nanofiber composites) used as catalyst for reduction of aromatic nitro compounds under mild conditions
-
Ionic liquid (1,1′-hexane-1,6-diylbis (3-methylpyridinium) tetrachloronickelate (II)) and PVDF-IL ([C6(mpy)2] [NiCl4]2-) nanofiber composites are synthesized and used as catalysts for the reduction of nitroarenes with NaBH4/H 2O system at ambient temperature. Ionic liquid containing nickel halide anion well dispersed on the PVDF nanofibers. It efficiently catalyzes the reduction of functionalized nitroarenes to the corresponding substituted anilines, avoiding the need for inert atmosphere, and additional base or other additives. The catalytic system gives good yields with other functional groups remaining intact.
- Chinnappan, Amutha,Kim, Hern
-
p. 3399 - 3406
(2013/03/29)
-
- Hydrogenation of nitroarenes using defined iron-phosphine catalysts
-
A novel iron-catalyzed hydrogenation of nitroarenes to the corresponding amines is reported. An in situ combination of Fe(BF4) 2·6H2O and phosphine allows for highly selective hydrogenation of a broad range of aromatic and nitroarenes tolerating different functional groups.
- Wienhoefer, Gerrit,Baseda-Krueger, Mario,Ziebart, Carolin,Westerhaus, Felix A.,Baumann, Wolfgang,Jackstell, Ralf,Junge, Kathrin,Beller, Matthias
-
supporting information
p. 9089 - 9091
(2013/09/24)
-
- Selective reduction of nitroarenes with molybdenum disulfide
-
Commercial MoS2 was found to be a highly selective catalyst for the reduction of nitrobenzenes to the corresponding anilines with hydrazine under mild conditions. MoS2 is not only much cheaper, but also more selective than noble metal catalysts for the reduction of functional nitrobenzenes to the corresponding anilines. Nitrobenzenes with halides (F, Cl, Br and I) were reduced selectively, and the corresponding anilines were obtained in excellent yields, and no dehalogenation was detected. Functional groups such as NH2, OH, alkene groups were tolerated during the reduction of the nitro compounds. The reduction of p-chloronitrobenzene was studied over MoS2 and Pd/C respectively with hydrazine. The yield of p-chloroaniline was much higher with MoS2 than that with Pd/C at full conversion. MoS2 was used as a catalyst for the reduction of nitrobenzene under mild conditions. Nitroarenes with halides (F, Cl, Br and I) were reduced selectively without dehaloganation, and functional groups such as NH2, OH, alkene groups were tolerated during the reduction of the nitro compounds. The reduction of p-chloronitrobenzene was studied over MoS 2 and Pd/C respectively with hydrazine. p-Chloroaniline was obtained quantitively with MoS2, but some aniline formed by dehaloganation with Pd/C. Copyright
- Huang, Lei,Luo, Pingfei,Xiong, Man,Chen, Rizhi,Wang, Yong,Xing, Weihong,Huang, Jun
-
p. 987 - 991
(2013/09/02)
-
- Selective hydrogenation of nitroarenes and olefins over rhodium nanoparticles on hydroxyapatite
-
We have demonstrated a highly active and selective nanocatalyst, Rh/HAP (rhodium supported on hydroxyapatite), for the reduction of nitroarenes with hydrazine and for the hydrogenation of olefins with hydrogen gas under mild conditions. Nitroarenes were hydrogenated selectively to the corresponding anilines over the Rh/HAP catalyst with hydrazine as reducing agent, and reducible groups, such as halides (fluorine, chlorine, bromine and iodine), cyano and alkene were untouched. Moreover, olefins can be hydrogenated selectively to the corresponding alkanes in good yields over the Rh/HAP catalyst in the presence of reducible nitro, carbonyl and cyano groups when H 2 was used.
- Huang, Lei,Luo, Pingfei,Pei, Weige,Liu, Xiaoyun,Wang, Yong,Wang, Jun,Xing, Weihong,Huang, Jun
-
supporting information
p. 2689 - 2694
(2013/01/15)
-
- Convenient and selective hydrogenation of nitro aromatics with a platinum nanocatalyst under ambient pressure
-
A convenient and highly selective platinum nanocatalyst was developed for the hydrogenation of nitro aromatics into the corresponding anilines at room temperature under ambient pressure. The platinum catalyst was highly active and selective for the hydrogenation of nitro aromatic compounds. Reducible groups such as aldehyde, ketone and nitrile were untouched during the hydrogenation of the corresponding nitro compounds, and the corresponding anilines were obtained quantitatively.
- Xu, Kunling,Zhang, Yuan,Chen, Xiaorong,Huang, Lei,Zhang, Rui,Huang, Jun
-
supporting information; experimental part
p. 1260 - 1264
(2011/06/25)
-
- General and selective iron-catalyzed transfer hydrogenation of nitroarenes without base
-
The first well-defined iron-based catalyst system for the reduction of nitroarenes to anilines has been developed applying formic acid as reducing agent. A broad range of substrates including other reducible functional groups were converted to the corresponding anilines in good to excellent yields at mild conditions. Notably, the process constitutes a rare example of base-free transfer hydrogenations.
- Wienhoefer, Gerrit,Sorribes, Ivan,Boddien, Albert,Westerhaus, Felix,Junge, Kathrin,Junge, Henrik,Llusar, Rosa,Beller, Matthias
-
experimental part
p. 12875 - 12879
(2011/10/03)
-
- Selective hydrogenation of nitroarenes using gum acacia supported Pt colloid an effective reusable catalyst in aqueous medium
-
An efficient green synthesis of Pt nanoparticles in water has been developed using gum acacia, both as reducing and stabilizing agent. The colloidal platinum efficiently catalyzes hydrogenation of nitroarenes to arylamines employing molecular hydrogen as the reductant. Excellent yields of products were obtained with a wide range of substrates and the catalyst was reused for several cycles with consistent activity.
- Sreedhar,Devi, D. Keerthi,Yada, Deepthi
-
experimental part
p. 1009 - 1014
(2012/01/06)
-
- Approaches to the synthesis of 2,3-dihaloanilines. Useful precursors of 4-functionalized-1 H-indoles
-
2,3-Dihaloanilines have been proved as useful starting materials for synthesizing 4-halo-1H-indoles. Subsequent or in situ functionalization of the prepared haloindoles allows the access to a wide variety of 2,4- or 2,3,4-regioselectively functionalized indoles in good overall yields. As no efficient synthetic routes to 2,3-dihaloanilines have been described in the literature, different approaches to the preparation of these 1,2,3-functionalized aromatic precursors are now presented. The most general one involves a Smiles rearrangement from the corresponding 2,3-dihalophenols and allows the preparation of 2,3-dihaloanilides in a straightforward and synthetically useful manner.
- Guilarte, Veronica,Castroviejo, M. Pilar,Garcia-Garcia, Patricia,Fernandez-Rodriguez, Manuel A.,Sanz, Roberto
-
p. 3416 - 3437
(2011/06/28)
-
- Selective reduction of nitro compounds using CeY zeolite under microwaves
-
Aliphatic and aromatic nitro compounds were selectively reduced to their corresponding amino derivatives in good yields using formic acid and CeY zeolite under monomode reactor. This system is found to be compatible with several sensitive functionalities. Beside the recycling result showed it had a long catalyst lifetime and could maintain activity even after being used for 20 cycles.
- Arya, Kapil,Dandia, Anshu
-
experimental part
p. 55 - 58
(2010/09/05)
-