- Reaction of aniline with ammonium persulphate and concentrated hydrochloric acid: Experimental and DFT studies
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In this paper, the reaction of aniline with ammonium persulphate and concentrated HCl was studied. As a result of our experimental studies, 2,4,6-trichlorophenylamine was identified as the main product. This shows that a high concentration of HCl does not favour oxidative polymerisation of phenylamine, even though the ammonium persulphate/HCl system is widely used in polyaniline synthesis. On the basis of the experimental data and density functional theory for reaction path modelling, we proposed a mechanism for oxidative chlorination of aniline. We assumed that this reaction proceeded in three cyclically repeated steps; protonation of aniline, formation of singlet ground state phenylnitrenium cation, and nucleophilic substitution. In order to confirm this mechanism, kinetic, thermochemical, and natural bond orbital population analyses were performed.
- Przybylek, Maciej,Gaca, Jerzy
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- Cobalt in N-doped carbon matrix catalyst for chemoselective hydrogenation of nitroarenes
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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
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p. 158 - 166
(2019/06/03)
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- Cobalt-based nanoparticles prepared from MOF-carbon templates as efficient hydrogenation catalysts
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The development of efficient and selective nanostructured catalysts for industrially relevant hydrogenation reactions continues to be an actual goal of chemical research. In particular, the hydrogenation of nitriles and nitroarenes is of importance for the production of primary amines, which constitute essential feedstocks and key intermediates for advanced chemicals, life science molecules and materials. Herein, we report the preparation of graphene shell encapsulated Co3O4- and Co-nanoparticles supported on carbon by the template synthesis of cobalt-terephthalic acid MOF on carbon and subsequent pyrolysis. The resulting nanoparticles create stable and reusable catalysts for selective hydrogenation of functionalized and structurally diverse aromatic, heterocyclic and aliphatic nitriles, and as well as nitro compounds to primary amines (>65 examples). The synthetic and practical utility of this novel non-noble metal-based hydrogenation protocol is demonstrated by upscaling several reactions to multigram-scale and recycling of the catalyst.
- Murugesan, Kathiravan,Senthamarai, Thirusangumurugan,Sohail, Manzar,Alshammari, Ahmad S.,Pohl, Marga-Martina,Beller, Matthias,Jagadeesh, Rajenahally V.
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p. 8553 - 8560
(2018/11/30)
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- An efficient method for reduction of nitroaromatic compounds to the corresponding aromatic amines with NH2NH2·H2O catalysed by H2O2-treated activated carbon
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An efficient and green protocol for the reduction of nitroaromatic compounds to the corresponding amines has been developed. The reduction catalyst system includes NH2NH2·H2O and H2O2-treated activated carbon. Without adding additional metals, the H2O2-treated activated carbon could be reused for many cycles without decreasing catalytic efficiency. The aromatic amines could be obtained in good to excellent yields.
- Jiang, Yuqin,Suo, Huajun,Zhang, Dandan,Li, Xiyong,Sun, Yamin,Ren, Baoqi,Zhang, Weiwei,Xu, Guiqing
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p. 509 - 512
(2017/10/03)
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- Story of an Age-Old Reagent: An Electrophilic Chlorination of Arenes and Heterocycles by 1-Chloro-1,2-benziodoxol-3-one
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By the use of 1-chloro-1,2-benziodoxol-3-one, an age-old reagent, the practical and efficient chlorination method is achieved. This hypervalent iodine reagent is amenable not only to the chlorination of nitrogen-containing heterocycles but also to selected classes of arenes, BODIPY dyes, and pharmaceuticals. In addition, the advantages, such as easy preparation and recyclable, air- and moisture-stable, in combination with the success in a gram-scale experiment grant this reagent great potential for industrial application.
- Wang, Mengzhou,Zhang, Yanyan,Wang, Tao,Wang, Chao,Xue, Dong,Xiao, Jianliang
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supporting information
p. 1976 - 1979
(2016/06/01)
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- A Doubly Biomimetic Synthetic Transformation: Catalytic Decarbonylation and Halogenation at Room Temperature by Vanadium Pentoxide
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The halogenation of the C?H bond by metal-oxo-peroxo species and the decarbonylation of aldehydes by metal-peroxo species are performed routinely in biological systems. However, metal-mediated decarbonylative halogenation is unknown in nature. In this work, we have shown that widely available V2O5 and VO(acac)2 (acac=acetylacetonate) can catalyze decarbonylative halogenation through the generation of an intermediate vanadium-oxo-peroxo species, which was characterized by using 51 V NMR, UV/Vis, and resonance Raman spectroscopy. Further detection of formic acid from the reaction mixture confirmed the biomimetic aspects of decarbonylative halogenation. A detailed experimental and DFT study indicated a concerted mechanism for this decarbonylative halogenation performed under simple and mild reaction conditions.
- Rana, Sujoy,Pandey, Bhawana,Dey, Aniruddha,Haque, Rameezul,Rajaraman, Gopalan,Maiti, Debabrata
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p. 3367 - 3374
(2016/11/16)
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- Nitrogen-doped graphene-activated iron-oxide-based nanocatalysts for selective transfer hydrogenation of nitroarenes
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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
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p. 1526 - 1529
(2015/03/14)
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- CFBSA: a novel and practical chlorinating reagent
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A structurally simple, highly reactive chlorinating reagent, N-chloro-N-fluorobenzenesulfonylamine (CFBSA), was conveniently prepared from inexpensive Chloramine B in high yield. A wide range of substrates were chlorinated with it to obtain products in good to high yields and appropriate selectivity.
- Lu, Zehai,Li, Qingwei,Tang, Minghua,Jiang, Panpan,Zheng, Hao,Yang, Xianjin
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supporting information
p. 14852 - 14855
(2015/10/06)
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- A quantitative assessment of the production of OH and additional oxidants in the dark Fenton reaction: Fenton degradation of aromatic amines
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This paper reports the results of a kinetic study into the transformation of 2,4- and 3,4-dichloroaniline (2,4-DCA, 3,4-DCA) and of methyl yellow (MY) with the Fenton reagent in aqueous solution. All the substrates can be degraded in the presence of Fe(II) + H2O2, but the reaction between Fe(II) and H2O2 causes substrate degradation and Fe(II) oxidation within seconds under the adopted conditions. The HPLC, GC-MS and IC analyses only allow the monitoring of the reaction after all Fe(II) has been consumed, when degradation proceeds more slowly via Fe(III) reduction to Fe(II). Substrate degradation in the first part of the reaction was studied by stopped-flow spectrophotometry, using MY as substrate. The results are consistent with a reaction involving OH, where both Fe(II) and H 2O2 compete with MY for the hydroxyl radical. However, the experimental data indicate that OH is unlikely to be the only product of the reaction between Fe(II) and H2O2. Another species, possibly the ferryl ion (FeO2+), is formed as well but has a negligible role in MY degradation. The Fenton reaction would thus yield both OH (about 60% at pH 2) and ferryl (about 40%), and the 60:40 branching ratio between OH and the other species is compatible with additional data here reported concerning the degradation of 2,4-DCA and 3,4-DCA in the first ferrous step of the Fenton reaction. The reported findings will hopefully indicate a way out of a long-lasting controversy concerning the mechanism of the Fenton process, also suggesting an approach to quantitatively determine the formation yields of the reactive species as well as a strategy to identify the reactant that is actually involved in substrate transformation.
- Minero, Claudio,Lucchiari, Mirco,Maurino, Valter,Vione, Davide
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p. 26443 - 26450
(2013/12/04)
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- Decarbonylative halogenation by a vanadium complex
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Metal-catalyzed halogenation of the C-H bond and decarbonylation of aldehyde are conventionally done in nature. However, metal-mediated decarbonylative halogenation is unknown. We have developed the first metal-mediated decarbonylative halogenation reaction starting from the divanadium oxoperoxo complex K3V5+2(O 22-)4(O2-)2(μ-OH) (1). A concerted decarbonylative halogenation reaction was proposed based on experimental observations.
- Rana, Sujoy,Haque, Rameezul,Santosh, Ganji,Maiti, Debabrata
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p. 2927 - 2932
(2013/04/24)
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- A new class of heterogeneous platinum catalysts for the chemoselective hydrogenation of nitroarenes
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A new series of nanostructured platinum catalysts able to catalyze the selective reduction of nitroarenes has been developed. The materials, made of organosilica physically doped with nanostructured platinum(0), are stable and efficient. Reactions in general proceed with high yield and often go to completion, while the catalysts can be reused in further reaction runs. This establishes a new class of relevant solid catalysts for synthetic organic chemistry named SiliaCat Platinum-Hydrogel.
- Pandarus, Valerica,Ciriminna, Rosaria,Beland, Francois,Pagliaro, Mario
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scheme or table
p. 1306 - 1316
(2011/06/25)
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- The use of sodium chlorate/hydrochloric acid mixtures as a novel and selective chlorination agent
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Sodium chlorate/hydrochloric acid mixtures were used to chlorinate activated arenes and the α-position of ketones. This chlorination method was used to produce selectively mono-, di-, and trichlorinated compounds by controlling the molarity of sodium chlorate. This reagent proved to be much more efficient and easier to handle than chlorine gas.
- Moon, Byung Seok,Choi, Han Young,Koh, Hun Yeong,Chi, Dae Yoon
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experimental part
p. 472 - 476
(2011/12/04)
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- Preparation of 2,4,6,-trichloroaniline from aniline using N-chloro reagents
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A product-by-process and method of manufacturing 2,4,6-trichloroanailine intermediates. The method of manufacturing 2,4,6-trichloroanailine intermediates by utilizing solvents and N-chlorinating reagents.
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Page/Page column 2-3
(2010/08/08)
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- Chlorination of aniline and methyl carbanilate by N-chlorosuccinimide and synthesis of 1,3,5-trichlorobenzene
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Aniline undergoes regioselective trichlorination by N-chlorosuccinimide (NCS) in acetonitrile in good yield. The product 2,4,6-trichoroaniline was converted into 1,3,5-trichlorobenzene by reduction of its diazonium salt. Reaction of the methyl carbamate of aniline with NCS gave only the 2,4-dichlorophenyl carbamate. Copyright Taylor & Francis Group, LLC.
- Davis, Matthew C.
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experimental part
p. 1100 - 1108
(2009/09/08)
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- Molecular rearrangement. 36. Selective α-CH oxidation of alkylarenes by nitrogen dioxide on thermolysis with nitramines
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Thermolysis of 2,4,6-trichloro-N-nitroaniline 1 and N-methyl-2,4-dinitro-N- nitroaniline 2 each with primaryl alkylbenzenes led to the formation of acylbenzenes. Similar reactions with secondary alkylbenzenes afforded a mixture of acetophenone and aliphatic aldehydes. Use of tert-butylbenzene in this reaction yielded formaldehyde and 2,3-diphenyl-2,3-dimethylbutane. The mechanisms of the studied reactions are discussed.
- Badr, Mahmoud Z. A.
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p. 6706 - 6710
(2007/10/03)
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- Oxidative halogenation of aromatic compounds with metal halides and sodium bismuthate
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A new mild and efficient method for aromatic halogenation with a wide variety of halides in the presence of sodium bismuthate NaBO3 in AcOH is reported. Metal halides of groups Ia, IIa, IIIa, IVa, Va, and the first row of transition elements are suitable for this method.
- Muathen, Hussni A.
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p. 164 - 168
(2007/10/03)
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- A newly developed synthesis of 1,3,5-trichlorobenzene (sym. TCB) from aniline
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1,3,5-Trichlorobenzene (sym. TCB) has been synthesised by diazotisation of 2,4,6-trichloroaniline (sym. TCA) (by converting aniline into anilinium chloride followed by its chlorination) in the presence of H2SO4/NaNO2 and H3PO2. The reaction parameters for the synthesis of both sym, TCA as well as sym. TCB have also been established in order to get better purity and higher yields, sym. TCA and sym. TCB have been characterized by elemental analysis, Fourier Transform Infra Red (FTIR) and NMR spectroscopy. Further, different reaction parameters for the nitration of sym. TCB to get 1,3,5- trichloro-2,4,6-trinitrobenzene (TCTNB) and its amination to get pure 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) have also been established. A comparison of properties of TATB obtained from imported sym. TCB and from laboratory prepared sym. TCB validates the product.
- Mehilal,Salunke,Agrawal
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p. 604 - 607
(2007/10/03)
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- Synthesis and characterization of 1,3-bis-(2,4,6-trichlorophenyl)-1H-triazene (BTCPT)
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1,3-Bis (2,4,6-trichlorophenyl)-1H-triazene (BTCPT) has been obtained as a by-product during the synthesis of 1,3,5-trichlorobenzene (Sym.TCB) by diazotization of 2,4,6-trichloroaniline in the presence of NaNO2/HCl and ethyl alcohol at 0-5°C and characterized by elemental analysis, IR, NMR and mass spectra.
- Mehilal,Salunke, Rajendra B.,Agrawal
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p. 1727 - 1729
(2007/10/03)
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- Synthesis of 2,6-disubstituted and 2,3,6-trisubstituted anilines
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A number of 2,6-disubstituted and 2,3,6-trisubstituted anilines have been prepared via the selective para dehalogenation of the corresponding anilines. Modification of the substituents on the amino nitrogen demonstrates that the selectivity is derived from steric rather than electronic effects. The effects of the choice of formate hydrogen donor, Pd catalyst, solvent, and temperature upon the efficiency and selectivity of the dehalogenation are discussed.
- Pews,Hunter,Wehrmeyer
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p. 4809 - 4820
(2007/10/02)
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- Direct determination of chlorination products of organic amines using membrane introduction mass spectrometry
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Direct analysis of organic chloramines in low concentrations in aqueous solutions is achieved by membrane introduction mass spectrometry. Tandem mass spectrometry allows structures of the chlorination products to be determined and shows that nitrogen chlorination occurs for aliphatic amines and ring chlorination for aniline. Monochlorination of aniline occurs mainly at the ortho position, while dichlorination yields 20-35% diortho and 80-65% ortho-para substitution products. Depending on the reaction conditions, the actual chlorination reagent can be chloramine, hypochlorous acid, and possibly chlorine. The high ortho chlorination yields of aniline are explained by a mechanism in which chlorination occurs first at the nitrogen atom with subsequent intramolecular rearrangement to the ortho position in analogy to rearrangement of the nitro group in N-nitro aromatic amines. Using flow injection analysis procedures, it is possible to follow in an on-line fashion reactions that yield (or remove) organic chloramines at sub parts per million levels.
- Kotiaho,Hayward,Cooks
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p. 1794 - 1801
(2007/10/02)
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- Highly Selective Aromatic Chlorinations. Part 2. The Chlorination of Substituted Phenols, Anisoles, Anilines, and Related Compounds with N-Chloroamines in Acidic Solution
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Phenols, anisoles, anilines, and related compounds are chlorinated in trifluoroacetic acid at room temperature by N-chlorodialkylamines and N-chlorotrialkylammonium salts.With monsubstituted compounds and their 2- and 3-substituted derivatives the reaction occurs efficiently and selectively at the 4-position.The reactivity of these substrates and the selectivity of their chlorinations are determined by electronic rather than steric effects of the substituent.Blocking the reaction with a substituent at the 4-position generally leads to only poor or moderate yields of the 2-chlorinated product.Evidence for radical and cation radical intermediates has been obtained in the reactions of some of the 4-substituted reactants and the mechanism of chlorination is discussed in the light of these findings.The reactions of selected substrates have been scaled up to give laboratory syntheses.
- Smith, John R. Lindsay,McKeer, Linda C.,Taylor, Jonathan M.
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p. 385 - 392
(2007/10/02)
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- New Azoolefines and their Acidic Cleavage to Aryldiimines
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3-Amino-1-aryl-3',3'-dimethyl-pyrazolin-4-spiro-2'-oxiran-5-ones (3a-c) undergo ring opening with methoxide forming methyl 3-amino-3-arylazo-propenoates (5a-c). 5a-c are cleaved under acidic conditions.The main products of the cleavage of 5c with methanolic hydrochloric acid are nitrogen, 2,4,6-trichloro-benzene (6), 2,4,6-trichloro-aniline (9) and 2,4,6-trichloro-phenylhydrazine (10).Intermediates of the cleavage of 5 are aryldiimines trapped with benzaldehyde as the corresponding benzhydrazides (12a,b).
- Kirschke, Klaus,Moeller, Angela,Schmitz, Ernst
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p. 893 - 898
(2007/10/02)
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- Process for the preparation of 2,4,6-trichloroaniline
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2,4,6-Trichloroaniline is prepared by reaction of aniline, which is optionally substituted by halogen, with a chlorinating agent in the presence of inert organic solvents and/or diluents at elevated temperatures.
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- CATALYTIC REDUCTION OF NITROSOBENZENE BY CARBON MONOXIDE USING NITROSOBENZENE COMPLEXES OF TRANSITION METALS
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New nitrosoarene complexes of ruthenium(II), palladium(II), platinum(II) and rhodium(I) have been synthesized.Their reactions with carbon monoxide have been studied in the solid state and in ethanol suspension.The results suggest formation of a nitrene intermediate.The catalytic reduction of nitrosobenzene has been also studied; azoxybenzene and urethane ate the main products in ethanol whereas azoxybenzene, phenyl isocyanate and diphenyl urea are obtained in benzene.Increase in the temperature and the carbon monoxide pressure results in increase of the yields of the carbonylated products.
- Vasapollo, G.,Nobile, C. F.,Giannoccaro, P.,Allegretta, F.
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p. 417 - 422
(2007/10/02)
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