Hydrogenation Of Aromatic Nitro Compounds Research Articles

Liquid phase catalytic transfer hydrogenation of aromatic nitro compounds on La1−xSrxFeO3 perovskites prepared by microwave irradiation

Abstract A series of La1−xSrxFeO3 (x = 0.0–1.0) oxides were prepared to study the influence of A-site substitution in perovskite-type mixed oxides LaFeO3 (ABO3-type perovskites) on the catalytic transfer hydrogenation of aromatic nitro compounds using propan-2-ol as hydrogen donor and KOH as promoter. The conventional method for the preparation of perovskites requires conductive heating for extended periods at elevated temperatures. We have used microwave irradiation method for the rapid synthesis of La1−xSrxFeO3 (x = 0.0, 0.2, 1.0) perovskites and the catalytic activity of these samples has been tested for the reduction of nitrobenzene. Kinetic studies have also been performed for nitrobenzene reduction.

Liquid phase catalytic transfer hydrogenation of aromatic nitro compounds on perovskites prepared by microwave irradiation

Preparation of specific tailor-made mixed oxides is one of the major topics of research in the field of heterogeneous catalysis. Perovskites are a class of mixed oxides, which have interesting catalytic and physicochemical properties. We have successfully developed a method using microwave irradiation to synthesize perovskites of the type LaMO 3 (M=Mn, Fe, Co, Cr, Al) in just 15 min. The LaMO 3 perovskites were used as catalysts for reduction of aromatic nitro compounds with propan-2-ol as hydrogen donor and KOH as promoter. Kinetics of the nitrobenzene reduction has also been studied.

Palladium colloids from an organometallic route: redox reaction between [VCp2] and [(Pd(η3-allyl)2Cl]2. Catalytic application to the hydrogenation of aromatic nitro compounds

[Pd(η3-C3H5)2Cl]2 reacts in THF in the presence of poly(vinylpyrrolidone) (PVP), with the 15-electron complex vanadocene [V(C5H5)2], to give PVP-protected palladium particles. High resolution electron microscopy (HREM) and wide angle X-ray scattering (WAXS) experiments were carried out on the PVP-protected palladium particles as obtained when exposed to H2 and O2 and after hydrogenation catalysis. In each case, the particles display the fcc lattice of bulk palladium and a narrow size distribution centred near 2–3 nm. Catalytic hydrogenation reactions of nitrotoluene and 2,4-dinitrotoluene into their corresponding aniline and 2,4-diaminotoluene were performed in CH2Cl2 and in H2O/CH2Cl2 biphasic conditions. The catalytic reactions were found to be zero order with respect to the substrate and first order with respect to dihydrogen and catalyst.

Palladium complex of poly(4-vinylpyridine- co-acrylic acid) for homogeneous hydrogenation of aromatic nitro compounds

Copolymers, poly(4-vinylpyridine- co-acrylic acid) (PVPA), with different composition were synthesized, and their palladium complexes were prepared. The catalytic properties of the palladium complex for the hydrogenation of aromatic nitro compounds were investigated. The palladium complex of PVPA can form a homogeneous system in ethanol. The optimum catalytic activity for hydrogenation of nitrobenzene was obtained when the molar content of 4-vinylpyridine (VPy) units in PVPA was 57.5% and VPy/Pd molar ratio was 6. The presence of 0.1 mol/l KOH can promote the catalytic activity to a great extent. In most cases, the hydrogenation of aromatic nitro compounds yields the corresponding aniline compounds almost quantitatively. The catalyst shows especially good activity for the hydrogenation of nitrophenols and nitroanisoles. The catalytic stability was also examined.

ChemInform Abstract: Catalytic Transfer Hydrogenation of Aromatic Nitro Compounds by Employing Ammonium Formate and 5% Platinum on Carbon.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Catalytic Liquid-Phase Reduction of Aromatic Nitro Compounds Containing Highly Reactive Functional Groups.

Improved procedures have been proposed for fast and selective hydrogenation of aromatic nitro compounds with the goal of obtaining practically important amines.

Catalytic Transfer Hydrogenation of Aromatic Nitro Compounds by Employing Ammonium Formate and 5% Platinum on Carbon

Aromatic nitro compounds were reduced to respective amines in high yields by using 5% platinum on carbon with ammonium formate or formic acid as hydrogen donor. It was observed that the former was more efficient donor than the later. Further we have found that reduction of nitro groups occurs without hydrogenolysis of halogens and the reducible substituents which remains unchanged under the reaction conditions.

A homogeneous catalyst made of poly(4-vinylpyridine- co- N-vinylpyrrolidone)-Pd(0) complex for hydrogenation of aromatic nitro compounds

Poly(4-vinylpyridine- co- N-vinylpyrrolidone)(VPy- co-NVP) and its palladium complex (VPy–NVP–Pd) were prepared. The palladium complex was used as catalyst for the hydrogenation of some nitroaromatics. The molar content of VPy units in VPy- co-NVP was determined as 31.25% by 1H NMR. VPy–NVP–Pd can be easily resolved in ethanol forming a homogeneous catalytic hydrogenation system together with substrates. The optimum catalytic activity for hydrogenation of nitrobenzene appeared when VPy/Pd molar ratio was 2. The catalytic behavior of the catalyst was found to be greatly affected by the type and concentration of added alkalies. The highest hydrogenation rate for nitrobenzene was found in a 0.1 mol/l ethanol solution of potassium hydroxide. The catalytic stability was examined by using nitrobenzene and 4-nitroanisole as substrates.

Catalytic Hydrogenation of Aromatic Nitro Compounds by Non-noble Metal Complexes of Chitosan

Silica-supported mono-metal (such as Ni, Cu) complexes and mixed metal (such as Cu/Zn, Cu/Cr) complexes of chitosan have been prepared. It is found that these non-noble metal complexes could be used as efficient catalysts for the hydrogenation of aromatic nitro compounds. The effects of type of metal, reaction temperature and pressure, solvent, nitrogen/metal molar ratio in the complex catalysts on the yields from nitrobenzene to aniline have been examined. It was also found that catalysts are active for the catalytic hydrogenation of other aromatic nitro compounds such as 2-nitroanisole, 2-nitroaniline, 2-nitrotoluene and 1-chloro-4-nitrobenzene.

Catalytic Hydrogenation of Aromatic Nitro Compounds by Non‐noble Metal Complexes of Chitosan

Catalytic Hydrogenation of Aromatic Nitro Compounds by Non‐noble Metal Complexes of Chitosan

Catalytic Activities of Poly-Schiff Base Pd (Ⅱ) Complexes in Hydrogenation of Aromatic Nitro-Compounds

Catalytic Activities of Poly-Schiff Base Pd (Ⅱ) Complexes in Hydrogenation of Aromatic Nitro-Compounds

Catalytic Activities of Poly-Schiff Base Pd (Ⅱ) Complexes in Hydrogenation of Aromatic Nitro-Compounds

Catalytic Activities of Poly-Schiff Base Pd (Ⅱ) Complexes in Hydrogenation of Aromatic Nitro-Compounds

Experimental study of thermal hazards during the hydrogenation of aromatic nitro compounds

Abstract Catalytic hydrogenations of aromatic nitro compounds are known to be potentially hazardous reactions. Their safety depends both on the properties of compounds and on the operating conditions. The focus of this paper is on thermal hazards. Firstly, the thermal stability of the reaction mixtures determines the temperature range in which the reaction can be run safely. Secondly, accumulation of hydroxylamine is a potential hazard as it can lead to undesired side-reactions, which are highly exothermic and, in contrast to the hydrogenation, cannot be controlled by the hydrogen supply. Using a reaction calorimeter, the thermal data of the reactions, i.e. overall heat and heat flow during the reaction, can be measured. Conclusions on the accumulation of intermediates in the reaction mixture can also be drawn from these data. Finally, the thermal behaviour of the reactor in the case of a cooling failure can be predicted with a high accuracy.

Nickel(II) and cobalt(II) phthalocyanines containing hindered phenols as redox catalysts in transfer hydrogenation of nitroaromatic compounds

Metallophthalocyanines (PcM) have been studied as catalysts for oxidation or reduction of different organic substrates. Much less attention has been directed to the catalytic processes under reducing conditions, when PcM serve as electron transer catalysts. In the transfer hydrogenation of nitroaromatic compounds by NaBH 4 in the presence of unsubstituted cobalt(II) phthalocyanine it was proposed that the catalyst undergoes one electron reduction at the metal centre to form PcCo which is the key-intermediate in the catalytic cycle

ChemInform Abstract: Selective Hydrogenation of Aromatic Nitro Compounds in the Presence of a Platinum Polyethylenimine Complex.

ChemInformVolume 21, Issue 5 Preparative Organic Chemistry ChemInform Abstract: Selective Hydrogenation of Aromatic Nitro Compounds in the Presence of a Platinum Polyethylenimine Complex. E. N. IZAKOVICH, E. N. IZAKOVICH Otd. inst. khim. fiz. im. Semenova AN SSSR, ChernogolovkaSearch for more papers by this authorA. N. SHUPIK, A. N. SHUPIK Otd. inst. khim. fiz. im. Semenova AN SSSR, ChernogolovkaSearch for more papers by this authorYU. M. SHUL'GA, YU. M. SHUL'GA Otd. inst. khim. fiz. im. Semenova AN SSSR, ChernogolovkaSearch for more papers by this author E. N. IZAKOVICH, E. N. IZAKOVICH Otd. inst. khim. fiz. im. Semenova AN SSSR, ChernogolovkaSearch for more papers by this authorA. N. SHUPIK, A. N. SHUPIK Otd. inst. khim. fiz. im. Semenova AN SSSR, ChernogolovkaSearch for more papers by this authorYU. M. SHUL'GA, YU. M. SHUL'GA Otd. inst. khim. fiz. im. Semenova AN SSSR, ChernogolovkaSearch for more papers by this author First published: January 30, 1990 https://doi.org/10.1002/chin.199005104AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume21, Issue5January 30, 1990 RelatedInformation

Selectivity in the hydrogenation of aromatic nitro-compounds in the presence of a platinum-polyethyleneimine complex

1. Complexes of platinum with polyethyleneimine have been synthesized and characterized by spectroscopic methods. 2. It has been shown that the complex Pt(II)-PEI, reduced with sodium borohydride, is an active and selective catalyst for the hydrogenation of aromatic nitro-compounds.

ニッケル触媒による水素化に関する研究 ＩＶ コロイド状の金属ニッケル触媒を用いる水素化反応 ニトロおよびハロゲン化合物の接触水素化

Colloidal nickel was easily prepared by reaction of nickel bromide with zinc powder. It was an active catalyst for hydrogenation of aromatic nitro compounds and of halobenzenes. Aromatic nitro compounds were hydrogenated to give the corresponding amines in high yields in the presence of the colloidal nickel under an atmospheric pressure of hydrogen. p-Bromonitrobenzene was hydrogenated successively to afford aniline via p-bromoaniline. p-Bromoaniline and p-chloroaniline were reduced to aniline in good yields. It is suggested that the amino moiety assists the adsorption of the substrate on the surface of the metal and that it acts as an acceptor of hydrogen halide. The hydrogenation of halobenzenes gave benzene in the presence of aniline. The reactivity of halobenzenes was in the following order;1>Br>Cl.kn-abstract=

Conversion of N-arylhydroxylamines in the presence of metal complexes and heterogeneous catalysts

The nature of the component distribution and the transformations in the catalytic hydrogenation of aromatic nitro compounds are analogous for the use of metal complex, colloidal, and heterogeneous catalysts. The hydrogenation features the formation of amino compounds due to disproportionation of intermediate N-arylhydroxylamines.

Catalytic transfer hydrogenation of aromatic nitro compounds in the presence of nickel thiolato-complexes

Transfer hydrogenation of aromatic nitro compounds by hydrazine to the corresponding anilines is catalyzed by (Bu4N)[Ni(tdt)2] (tdt=toluene-3,4-dithiolate) and analogous NiIII complexes in refluxing THF; hydroxylamine derivatives are formed as intermediates.

Hydrogenation of Aromatic Nitro Compounds with A Pt/SiO2–AlPO4 Catalyst

Abstract In this work we have carried out the reduction of aromatic nitro compounds bearing different substituents with gaseous hydrogen, over a Pt catalyst (3% by weight) supported on a SiO2–AlPO4 system. The catalyst was obtained by impregnation, the impregnating metal salt being reduced with α-phellandrene. The kinetic data found allow us to describe the reduction of nitrobenzene as a Langmuir–Hinslwood kinetic. The sequence of reaction rates for the different nitro compounds assayed conforms to the Hammett–Taft equation, which allows relating the electron density of the aromatic ring to the reduction rate of the nitro group. Finally, we propose mechanism for the process, characterized by the absence of intermediates with net charges.