Showing papers on "Nitrobenzene published in 1991"
TL;DR: In this article, the reverse sequence of events is observed: chemisorption of Ag(CN)2- on silver particles, producing an excess positive charge inside the particles, followed by complete reduction of the Ag+ ions of the adsorbed complexes by excess electrons that are deposited by a reducing reagent (i.e., organic radicals generated radiolytically).
Abstract: Colloidal silver particles (3-nm diameter) are oxidized in the absence of air by organic and inorganic electron acceptors (such as nitrobenzene, methylviologen, nitropyridine oxide, and hexacyanoferrateIII) when nucleophilic reagents (such as CN- and SH-) are present in the solution. The mechanism of catalyzed metal oxidation proposed previously,2 according to which the interaction of surface atoms with the nucleophiles leads to an excess negative charge in the metal interior which can be picked up by the electron acceptors, explains the observed phenomena. This mechanism contains reversible steps. An experiment is reported in which the reverse sequence of events is observed: chemisorption of Ag(CN)2- on silver particles, producing an excess positive charge inside the particles, followed by complete reduction of the Ag+ ions of the adsorbed complexes by excess electrons that are deposited by a reducing reagent (i.e., organic radicals generated radiolytically). Ag(CN)2- ions in solution are not reduced by radicals. © 1991 American Chemical Society.
194 citations
TL;DR: In this article, the Fenton reaction has been used for the purification of wastewaters contaminated with nitrophenols, which are toxic pollutants, difficult to decompose by other means.
173 citations
TL;DR: Results indicate that the nitrobenzene ring is subject to initial attack by both mono- and dioxygenase enzymes.
Abstract: Nonpolar nitroaromatic compounds have been considered resistant to attack by oxygenases because of the electron withdrawing properties of the nitro group. We have investigated the ability of seven bacterial strains containing toluene degradative pathways to oxidize nitrobenzene. Cultures were induced with toluene vapor prior to incubation with nitrobenzene, and products were identified by high-performance liquid chromatography and gas chromatography-mass spectrometry. Pseudomonas cepacia G4 and a strain of Pseudomonas harboring the TOL plasmid (pTN2) did not transform nitrobenzene. Cells of Pseudomonas putida F1 and Pseudomonas sp. strain JS150 converted nitrobenzene to 3-nitrocatechol. Transformation of nitrobenzene in the presence of 18O2 indicated that the reaction in JS150 involved the incorporation of both atoms of oxygen in the 3-nitrocatechol, which suggests a dioxygenase mechanism. P. putida 39/D, a mutant strain of P. putida F1, converted nitrobenzene to a compound tentatively identified as cis-1,2-dihydroxy-3-nitrocyclohexa-3,5-diene. This compound was rapidly converted to 3-nitrocatechol by cells of strain JS150. Cultures of Pseudomonas mendocina KR-1 converted nitrobenzene to a mixture of 3- and 4-nitrophenol (10 and 63%, respectively). Pseudomonas pickettii PKO1 converted nitrobenzene to 3- and 4-nitrocatechol via 3- and 4-nitrophenol. The nitrocatechols were slowly degraded to unidentified metabolites. Nitrobenzene did not serve as an inducer for the enzymes that catalyzed its oxidation. These results indicate that the nitrobenzene ring is subject to initial attack by both mono- and dioxygenase enzymes.
122 citations
TL;DR: In this paper, detailed mechanisms are outlined for the chemical reactions that contribute to in-situ formation and atmospheric removal of selected aromatic toxic air contaminants. But in this paper, we focus on the removal of xylenes (dimethyl phenols).
77 citations
TL;DR: In this paper, it was shown that palladium metal supported on alumina is an effective catalyst for the formation of phenyl isocyanate, PhNCO, when activated by ortho-phenanthroline or its derivatives, and by 2,4,6-trimethylbenzoic acid (TMBA) (T = 180 °C, P(CO) = 40 atm, in dry benzene).
68 citations
TL;DR: In this paper, the electrocatalytic hydrogenation of benzene, aniline, and nitrobenzene at a Raney nickel powder cathode was investigated at a single phase electrolyte consisting of t-butanol, water, and a hydrotropic salt, either sodium or tetraethylammoniump-toluenesulphonate (TEATS).
Abstract: The electrocatalytic hydrogenation of benzene, aniline, and nitrobenzene was investigated at a Raney nickel powder cathode. The single phase electrolyte consisted of t-butanol, water, and a hydrotropic salt, either sodium or tetraethylammoniump-toluenesulphonate (TEATS). The hydrogenation of benzene was achieved only in the latter case; the only product detected was cyclohexane. The highest current efficiency (73%) was obtained at 50° C, 1.0m benzene, 2.5m TEATS, and at an apparent current density of 4.0 mA cm−2. Aniline was electrocatalytically hydrogenated to cyclohexylamine only in the presence of a quaternary ammonium ion supporting electrolyte (containing either Br− orp-toluenesulphonate anions), with product current efficiencies of ∼40%. When nitrobenzene was hydrogenated with a sodiump-toluenesulphonate supporting electrolyte, only nitro group reduction was observed. When the supporting electrolyte was TEATS, both nitro group reduction and aromatic ring hydrogenation occurred.
35 citations
TL;DR: In this article, N,N'-Diphenylurea has been synthesized from nitrobenzene, aniline, and carbon monoxide in a batch reactor at 80-160 o C and 15-75 bar.
Abstract: N,N'-Diphenylurea has been synthesized from nitrobenzene, aniline, and carbon monoxide in a batch reactor at 80-160 o C and 15-75 bar. Homogeneous catalyst systems consisting of a palladium(II) salt, an onium salt, and triphenylphosphine dissolved in xylene or toluene were found to be highly efficient, giving isolated urea yields up to 98% at 100% nitrobenzene conversion. The effects of catalyst composition and other reaction variables were studied
34 citations
TL;DR: In this paper, a linear free-energy relationship between the ionization potential of the hydrogen donor and the logarithm of the decomposition rate was inferred from kinetic studies and product analysis.
Abstract: Several nitroarenes were decomposed isothermally in dilute supercritical solution in benzene or toluene and in the vapor phase in the temperature range of 290-380°C in sealed glass tubes with pressures up to 100 MPa. The mechanisms of thermolysis are inferred from kinetic studies and product analysis. The intial rate-controlling step for nitrobenzene and p-nitrotoluene decompsition is probably intermolecular hydrogen abstraction to form an ArNO 2 H radical intermediate. The nature of the transition state is deduced from the activation volume (ΔV*), H/D kinetic-isotope effect, and a linear free-energy relationship between the ionization potential of the hydrogen donor and the logarithm of the decomposition rate. A concurrent pathway for o-nitrotoluene is an intramolecular reaction in which anthranil is an intermediate. Activation parameters are given and detailed mechanisms proposed
29 citations
TL;DR: The selectivity of N-phenyl carbamate from reductive carbonylation of nitrobenzene using Rh(CO)4− or Ru3(CO 12Et4N+Cl− as the catalyst is much higher in t-butyl alcohol than in primary or secondary alcohols as discussed by the authors.
25 citations
TL;DR: In this paper, a systematic study has been carried out on the quenching of positronium (Ps) atoms by nitrobenzene in various solvents.
Abstract: A systematic study has been carried out on the quenching of positronium (Ps) atoms by nitrobenzene in various solvents. In order to see the effect of the energy level of Ps, in the localized bubble state, on the quenching capability of nitrobenzene, overall second-order rate constants were plotted against solvent surface tensions. It was found that the rate constant increased with increasing surface tension up to a critical value of ca. 26 dyn cm–1, corresponding to a Ps bubble energy of 1.24 eV. In liquids where the Ps energy is higher than this, the rate constant decreased with increase in solvent viscosity, as is expected for a diffusion-controlled reaction.
24 citations
TL;DR: In this article, the ion-transfer voltammetry of the hexamolybdate ion Mo6O192− at the nitrobenzene (NB)/water (W) interface was studied.
Abstract: Transfer of the hexamolybdate ion, Mo6O192−, at the nitrobenzene(NB)/water(W) interface was studied by ion-transfer voltammetry. The Mo6O192− ion decomposed immediately after being transfered from NB to W. In the presence of orthophosphate ions in the weakly acidic W phase (pH 3.1), molybdophosphate anions, i.e. [H3PMo11O39]4−, were formed at the interface. A well-defined voltammetric wave due to the transfer of complex anions from W to NB was observed; the peak current was proportional to the bulk concentration of orthophosphate ions. Thus, the NB/W interface containing Mo6O192− in NB can function as an ion-selective electrode surface for a voltammetric determination of orthophosphate ions.
Patent•
01 Sep 1991
TL;DR: In this article, a process for the continuous preparation of aniline by hydrogenating nitrobenzene is disclosed which comprises the steps of suspending, in an anilines solvent, a catalyst of palladium or palladium-platinum which is deposited on a lipophilic carbon having an oil absorbency of at least 100.
Abstract: A process for the continuous preparation of aniline by hydrogenating nitrobenzene is disclosed which comprises the steps of suspending, in an aniline solvent, a catalyst of palladium or palladium-platinum which is deposited on a lipophilic carbon having an oil absorbency of at least 100, adding a zinc compound and an alkali metal carbonate or a zinc compound and an alkali metal bicarbonate as promotors to the reaction system, and carrying out reaction at a temperature of from 150 to 250° C. substantially in the absence of water while aniline and water formed in said reaction are continuously distilled off as vapor from the reaction product, and the concentration of nitrobenzene in the reaction solution is maintained at 0.01% by weight or less.
TL;DR: In this article, the extraction of cesium and chemical stability of 14 dicarbollide and 5 dicaraundecaborate extractants were investigated, and it was shown that the hexachlorinated and hexabrominated derivatives are chemically the most stable.
Abstract: The extraction of cesium and chemical stability of 14 dicarbollide and 5 dicarbaundecaborate extractants were investigated. The hexachlorinated and hexabrominated dicarbollides are chemically the most stable. The extraction of the derivatives into nitrobenzene was correlated with HANSCH's hydrophobicity increments.
TL;DR: In this article, the rate of electron transfer between hexacyanoferrate(III) in water and ferrocene in nitrobenzene has been investigated by the ac impedance measurements at an equilibrium potential E dc.
TL;DR: In this article, model liquid mixtures of organic compounds containing nitrogen were burned in a laboratory fluidized bed reactor at temperatures ranging from 700 to 900 °C and oxygen concentrations ranging from 2 to 15 vol%.
TL;DR: In this article, the non-resonant part of the static non-linear susceptibility χ(3)1212 (ω 1,−ω1,o,o) in acetonitrile, benzaldehyde, acetophenone, acetone, ethyl methyl ketone, o-nitrotoluene, nitrobenzene, and benzoylchloride are reported.
TL;DR: The (TPP)FeCl-NaBH4 system performs remarkably efficient catalytic reduction of nitrobenzene to aniline as discussed by the authors, while their catalytic activities are much lower than that of (TPP]FeCl.
Abstract: The (TPP)FeCl–NaBH4 system performs remarkably efficient catalytic reduction of nitrobenzene to aniline. (TPP)Co and (TPP)MnCl also catalyze the reduction of p-chloronitrobenzene to p-chloroaniline, while their catalytic activities are much lower than that of (TPP)FeCl.
TL;DR: In this article, the adsorption of nitrobenzene and benzonitrile on a silver electrode was studied with surface enhanced Raman spectroscopy SERS.
Journal Article•
TL;DR: In this article, the acid-catalysed multi-electron reduction of nitrobenzene derivatives by an acid-stable NADH analogue, 10-methyl-9,10-dihydroacridine, occurs efficiently under mild conditions in the presence of perchloric acid in acetonitrile.
Abstract: Acid catalysed multi-electron reduction of nitrobenzene derivatives by an acid-stable NADH analogue, 10-methyl-9,10-dihydroacridine, occurs efficiently under mild conditions in the presence of perchloric acid in acetonitrile. Observation of CIDNP spectra as well as detailed kinetic studies on the acid catalysed reduction of nitrobenzene derivatives by AcrH2 and on the acid catalysed electron transfer from the excited state of [Ru(bpy)3]2+ to nitrobenzene derivatives has revealed that the multi-electron reduction of nitrobenzene derivatives by AcrH2 proceeds via acid catalysed electron transfer radical-chain reactions in which hydrogen transfer from AcrH2 to radicals produced by the acid catalysed one-electron reduction of nitrobenzene derivatives is the rate determining propagation step.
TL;DR: In this paper, the authors proposed a method to solve the problem of "in-situ" in the context of games, where the game is played in a virtual world.
Abstract: 水/油/水の3層人工液膜から成る化学振動系において,界面張力変化から単分子膜を検出する非接触でin-situな計測法として,準弾性レーザー散乱法を適用するための基礎実験を行った.水/ニトロベンゼン界面にジパルミトイルポスファチジルコリンの単分子膜を展開し,膜の分子密度を変化させ,界面張力波(リプロン)の周波数の変化を測定して界面張力の変化を求めた.理論解析の結果と比較することにより,本方法で単分子膜をモニターできることを示した.
TL;DR: In this paper, the role of aggregation is attributed to the assistance of excess reagent molecules in the product formation process in the reaction of aryliminodimagnesium [ArN(MgBr)2 (IDMg)] with nitrobenzene.
Patent•
31 Jul 1991
TL;DR: In this article, the Ullmann reaction was used to obtain a new diamine compound, useful as a charge transport layer of photoreceptors or electroluminescent elements.
Abstract: PURPOSE:To obtain a new diamine compound, useful as a charge transport layer of photoreceptors or electroluminescent elements, capable of providing the photoreceptors excellent in characteristics such as sensitivity, charge transport properties or initial surface potential and improved in ozone resistance and light stability CONSTITUTION:A diamine compound expressed by formula I (Ar1 and Ar2 are alkyl, aralkyl, etc; R1 to R4 are H, alkyl, etc; X is O, S, etc), eg a compound expressed by formula II The aforementioned compound is obtained by carrying out the Ullmann reaction of, eg an iodide expressed by formula III with an amino compound expressed by formula IV in the presence of a basic compound catalyst such as a carbonate of an alkali metal in an aprotic polar solvent such as nitrobenzene at 100-250 degC under ordinary pressure For example, N-biphenyl-N-p-tolylamine is used as the amino compound expressed by formula IV
TL;DR: In this article, the potential step chronoamperometry and cyclic voltammetry were interpreted in terms of the facilitated transfer of protons from the water to the nitrobenzene phase by the dissociated form.
TL;DR: The dependence of the distribution of Cs, Sr, Ba, Eu, Ce between nitric acid solutions and 0.06M hexabromo derivative of cobalt dicarbollide in dichloroethane has been investigated in this article.
Abstract: The dependence of the distribution of Cs, Sr, Ba, Eu, Ce between nitric acid solutions and 0.06M hexabromo derivative of cobalt dicarbollide (H+BBr
6
−
) in dichloroethane has been investigated upon the concentration of the acid, the extractant and the synergistic additive Slovafol 909. The back-extraction due to the presence of propanol, hydrazine, nitric acid and NH4NO3 has been studied. The results were similar to those observed in analogous systems using nitrobenzene as the solvent.
TL;DR: In this paper, the possibility of using aliphatic alcohols as hydrogen donors for the catalytic transfer reduction of nitro group over MgO was examined, and an effective and selective method was found to be effective and a selective method for reduction of 4-nitrotoluene, 4-chloronitrobenzene,4-nitro-m-xylene, β-nitrogen-styrene, 3-nitropane, 3−nitro benzaldehyde, 1−nitrogenpropane, and 1−butane.
Abstract: Summary The possibility of using of aliphatic alcohols as hydrogen donors for the catalytic transfer reduction of nitro group over MgO was examined. Catalytic hydrogen transfer was found to be effective and selective method for reduction of nitrobenzene, 4–nitrotoluene, 4–chloronitrobenzene, 4–nitro-m-xylene, β–nitro-styrene, 3–nitrobenzaldehyde, 1–nitropropane, and 1–nitrobutane. Conversion of starting nitro compound into desired product depended on the alcohol used as a donor. Adsorption of reactant and catalyst deactivation were studied by esr. New aspects of a role of one-electron donor sites in hydrogen transfer over MgO were demonstrated.
TL;DR: In this paper, UV laser irradiation of mixtures of n-heptane with acetophenone, benzaldehyde or nitrobenzene has been shown to induce C C bond breaking in n-Heptane and a dehydrocyclization reaction occurs to form alkenes, benzene and toluene.
TL;DR: In this article, experimental observations of the variation of Kerr constant in five binary liquid mixtures of acetonitrile in benzene, toluene, nitrobenzene, chlorobenzene and o-nitrotoluene with different molar fractions were reported.
TL;DR: In this paper, radiolysis of nitrobenzene solution of cobalt(III) dicarbollide, which is used for solvent extraction of cesium from fission products results in enhanced extraction of niobium-95.
Abstract: Radiolysis of nitrobenzene solution of cobalt(III) dicarbollide, which is used for solvent extraction of cesium from fission products results in enhanced extraction of niobium-95. The isomeric nitrophenols, 2,4-dinitrophenol, p-nitrosophenol and m-aminophenol exhibit antergism towards extraction of niobium cations. Synergistic effect is exhibited by 2,5-dinitrophenol, o- and p-aminophenol, o-nitroaniline and 2,4,6-trinitrophenol which are among the products of two-phase systems with nitrobenzene radiolysis. Two competing processes, complexation of niobium and protonation of ligand, both depending on the ligand benzene ring substituents, are discussed.