Showing papers on "Nitrobenzene published in 1989"
TL;DR: In this paper, the electrochemical reduction of nitrobenzene, azoxybenzenes, azobenzene, phenylhydroxyl-amine and hydrazobenzenes was studied at polycrystalline copper and nickel electrodes in neutral and basic aqueous methanolic solutions.
51 citations
TL;DR: In this paper, a new approach for the determination of solvent strength and selectivity in gas chromatography based on thermodynamic considerations is proposed, where the solvent strength is defined as the partial molar Gibbs free energy of solution for a methylene group per unit solvent volume.
49 citations
39 citations
TL;DR: The temperature required for the anodic conversion of an organo-solv spruce lignin, in aqueous alkaline solution, may be lowered by the addition of nitrobenzene or 1,3-dinitrobenzinene.
Abstract: The temperature required for the anodic conversion of an organo-solv spruce lignin, in aqueous alkaline solution, may be lowered by the addition of nitrobenzene or 1,3-dinitrobenzene. The additives cause significant and reproducible changes in the Tafel plot for the reaction. Preparativescale experiments are less reproducible although the range of phenolic products is generally similar to that produced by conventional nitrobenzene oxidation or by anodic oxidation at higher temperatures.
37 citations
TL;DR: In this paper, the rate constants for electrochemical exchange, k ex, have been measured for the cobalt clathrochelate couples Co(dmg) 3 (BF) 2 +/0 and Co[dmg] 3 (BC 4 H 9 ) 2 + /0 (dmg = double deprotonated dimethylglyoxime) at gold and mercury electrodes in six solvents to ascertain whether the solvent relaxation dynamics provide a significant contribution to the solvent-dependent reaction rates.
31 citations
TL;DR: In this article, the electrochemical detector was not affected by nitrobenzene interference and allowed the direct injection of nitron-bene hydrolysates into HPLC, resulting in a simplified analytical procedure with quantitative results and improved detection limits.
Abstract: Results showed that solvent partitioning with CH 2 Cl 2 was biased by losses of phenolics ranging from 10% for vanillin and syringaldehyde to 75% for p-coumaric acid. Yields improved by saturating the water phase with sodium chloride yet remained nonquantitative. The electrochemical detector was not affected by nitrobenzene interference and allowed the direct injection of nitrobenzene hydrolysates into HPLC, resulting in a simplified analytical procedure with quantitative results and improved detection limits
30 citations
TL;DR: In this paper, a multi-step catalytic reduction scheme is proposed for the reduction of nitro-benzene to anilines by CO and H 2 O. Analysis of the reaction solution in the reaction involving nitrobenzenes has revealed the presence of several complexes, including (η 4 -Ph 4 −Ph 4 C 4 4 C=O)(CO) 2 Ru(H 2 NPh) (5 ), which was prepared independently; the behaviour of 5 under catalysis conditions was studied.
24 citations
TL;DR: The electrochemical reduction of nitrobenzene and phenylhydroxylamine on rotating (bulk or electrodeposited) copper electrodes has been investigated as a function of the pH in water + ethanol solutions as discussed by the authors.
24 citations
TL;DR: In this paper, a method of experimental estimation of the differences of surface potentials between organic solvents and water, Δswχ, by means of voltaic cells with transport (using the dynamic condenser method) is presented.
22 citations
TL;DR: In this paper, the formation yields of phenol and nitrobenzene (from benzene) and of the products (III)-(VII) were determined by means of gas chromatography with flame ionization detection.
Abstract: The formation yields of phenol and nitrobenzene (from benzene) and of the products (III)-(VII) are determined by means of gas chromatography with flame ionization detection.
20 citations
TL;DR: The biodegradation of nitrobenzene and 2,4-dinitrophenol in NB plant wastewater has been studied using acclimated activated sludge in a batch bioreactor and the gas chromatographic monitoring shows simultaneous utilization of these two substrates.
TL;DR: In this article, the response characteristics of several ions, usually considered as electroinactive, were investigated at the thin-layer amperometric detector based on ion transfer across the interface of water/nitrobenzene solidified by polyvinyl chloride and agar.
Abstract: The response characteristics of several ions, usually considered as electroinactive, were investigated at the thin-layer amperometric detector based on ion transfer across the interface of water/nitrobenzene solidified by polyvinyl chloride and agar. The influence of some factors, such as applied potential, flow rate of mobile phase, and organic solvent in mobile phase, was studied by flow injection analysis of cations (choline, acetylcholine, tetramethylammonium, tetrabutylammonium, and cesium) and anions (ClO, IO, and ReO). The detection limit of the flow injection amperometric detector is in the range of 4 to 40 ng of these ions. Reversed-phase chromatographic separation of choline and acetylcholine with amperometric detection was demonstrated.
TL;DR: Identification du nitrobenzene lors de la reduction electrochimique du nitronzene is described in this article, where the chromatographie HPLC couplee a un reacteur electrochemique a ecoulement.
Patent•
12 May 1989TL;DR: In this article, Nitrobenzenes are prepared by nitrating benzenes in vapor phase using nitric acid as a nitrating agent and under continuous or intermittent feeding of sulfuric acid as the catalyst.
Abstract: Nitrobenzenes are prepared by nitrating benzenes in vapor phase using nitric acid as a nitrating agent and under continuous or intermittent feeding of sulfuric acid as a catalyst in the presence of a catalyst comprising sulfuric acid supported on a carrier or in the presence of only a carrier. This process can provide very high and prolonged nitration activity.
TL;DR: Several hydrocarbons reacted with caesium fluoroxysulphate in acetonitrile at 35°C yielding mono and disubstituted products as discussed by the authors.
TL;DR: In this article, a new explanation is proposed of the anomalous magnetic quenching of positronium found by others for solutions of nitrobenzene in hexane, but not benzene and cyclohexane.
TL;DR: The ruthenium cluster [Ph4P][Ru3(CO)10(PhNCHO)] has been structurally characterised and shown to play an important role in the hydroxide- or methoxide-promoted reductive carbonylation of nitrobenzene as discussed by the authors.
Abstract: The ruthenium cluster [Ph4P][Ru3(CO)10(PhNCHO)] has been structurally characterised and shown to play an important role, along with its precursor [Ph4P][HRu3(CO)9(PhNCO)], in the hydroxide- or methoxide-promoted reductive carbonylation of nitrobenzene
TL;DR: In this article, the luminescence quenching of uranyl ion with cyclohexane, benzene, toluene, anisole and nitrobenzene during its photochemical reduction with triphenylphosphine was studied.
Abstract: The luminescence quenching of uranyl ion with cyclohexane, benzene, toluene, anisole and nitrobenzene during its photochemical reduction with triphenylphosphine was studied. The results show that the substituents have a remarkable effect on the aromatic ring which operates in accordance with the inductive effect. Because of the positive inductive effect of the methyl and methoxy groups on the phenyl ring, there is an increased electron density for exciplex formation, and this results in a high value for physical quenching of optically excited uranyl ion with anisole; the value is low with nitrobenzene owing to the negative inductive effect of the nitro group.
TL;DR: In this paper, preliminary results of ATR/FTIR experiments indicate that thinly coating the ATR elements with suitable polymers improves the ability to detect test analytes in aqueous solutions.
Abstract: Preliminary results of ATR/FTIR experiments indicate that thinly coating the ATR elements with suitable polymers improves the ability to detect test analytes in aqueous solutions. Experiments were performed using the test analyte, nitrobenzene, in aqueous solutions containing a range of methanol concentrations. the time dependence and effect of methanol concentration on the nitrobenzene IR absorbance was investigated.
TL;DR: In this paper, a number of new solvents used as the organic phase of electrochemical measurement at liquid-liquid interfaces, including phenyl isothiocyanate, o-dichlorobenzene, benzyl cyanide, propiophenone, methyl cyclohexanone and methyl amyl ketone, have been studied.
Abstract: Solvents used as the organic phase of electrochemical measurement at liquid-liquid interfaces, including phenyl isothiocyanate, o-dichlorobenzene, benzyl cyanide, propiophenone, methyl cyclohexanone, cyclohexanone, and methyl amyl ketone, have been studied. Mixing solvents of different polarities in different ratios gives a number of new solvent systems that are suitable for showing a useful “potential window,” including the mixed-solvent systems with nitrobenzene plus phenyl isothiocyanate, nitrobenzene plus o-dichlorobenzene, nitrobenzene plus ketones, and the mixed solvent without nitrobenzene, such as phenyl isothiocyanate plus benzyl cyanide, phenyl isothiocyanate plus benzonitrile, o-dichlobenzene plus benzyl cyanide, and chlorobenzene plus benzonitrile. Supporting electrolytes such as cetylpyridinium tetraphenylborate, ethyl violet tetraphenylborate, and triheptyl dodecylammonium tetraphenylborate are also introduced as the organic phase in order to extend the potential range in the negative direction.
TL;DR: A nitrate-sensitive electrode based on the ionic associates between bis(triphenylphosphine)iminium and nitrate ions in nitrobenzene solution is proposed and can be used for determinations of 10(-5) 0.1M nitrate in aqueous solutions.
TL;DR: In this article, the reduction of nitrobenzene to aniline by Fe3(CO)12 under triphase conditions has been investigated and the efficiency of the polymer-supported phase transfer agents compared.
TL;DR: Friedel-Crafts acetylation of phenanthrene (1a) in sym-tetrachloroethane yields mixtures of 2-, 3- and 9-acetylphenanthrenes (2a, 3a, 4).
Abstract: Friedel-Crafts acetylation of phenanthrene (1a) in sym-tetrachloroethane yields mixtures of 2-, 3- and 9-acetylphenanthrenes (2a, 3a, 4). The distribution of isomers is found to depend strongly upon the method of mixing the reagents. Acetylation of 9-chlorophenanthrene (1b), performed by a variety of methods and solvents, led mainly to 3-acetyl-9-chlorophenanthrene (3b) (≥85%). Previously unreported 2-acetyl-9-chlorophenanthrene (2b) was found to form up to a maximum 11% in nitrobenzene.
TL;DR: In this article, three commercial Kieselguhr-supported copper, nickel and coppernickel catalysts were investigated under severe conditions in the hydrogenation of nitrobenzene to aniline.
TL;DR: In this article, the effects of the concentrations of base and rhodium complex, and the presence of substituents in the phosphine ligand on the rate and selectivity of the reaction were studied.
TL;DR: Acid-catalysed multi-electron reduction of nitrobenzene derivatives by a dihydronicotinamide adenine dinucleotide (NADH) model compound proceeds efficiently under mild conditions in the presence of perchloric acid in acetonitrile.
Abstract: Acid-catalysed multi-electron reduction of nitrobenzene derivatives by a dihydronicotinamide adenine dinucleotide (NADH) model compound proceeds efficiently under mild conditions in the presence of perchloric acid in acetonitrile.
Patent•
19 Jun 1989TL;DR: In this article, a process for the preparation of concentrated storage-stable aqueous solutions of yellow azo-and azoxystilbene dyes which are obtained by self-condensation of 4-nitrotoluene-2-sulfonic acid in the presence of an alkali metal hydroxide was described.
Abstract: The invention relates to a process for the preparation of concentrated storage-stable aqueous solutions of yellow azo- and azoxystilbene dyes which are obtained by self-condensation of 4-nitrotoluene-2-sulfonic acid in the presence of an alkali metal hydroxide, by converting the sparingly soluble alkali metal salt of the dye into a water-soluble ammonium salt by double cation exchange via a lipophilic ammonium salt, which process comprises carrying out the double ion exchange in a two-phase system of nitrobenzene/water and using, for the first ion exchange a di- or trialkylamine containing a total of 12 to 40 carbon atoms and, for the second ion exchange, a mono-, di- or trialkanolamine containing 2 to 4 carbon atoms in each alkyl moiety. The concentrated storage-stable dye solutions so obtained are particularly suitable for dyeing paper.
TL;DR: In this paper, the catalyseur est prepare par reaction de la H-montmorillonite avec la triethoxysilyl-3 propylamine suivie d'une complexation avec Pd(PhCH 2 CH) 2 Cl 2
TL;DR: In this article, the authors measured the high resolution Raman spectra of a multilayer of nitrobenzene (1000 L) absorbed on a well characterized surface of Ni(111) prepared in ultrahigh vacuum, and investigated the nature of the thin film formed by gaseous exposure.
TL;DR: In this article, a method was developed for the extraction of rhenium/VII/ with methylene blue with Nitrobenzene and the stoichiometry of metal to reagent determined by the method of substoichiometric extraction and slope-ratio method was found to be 1∶1.
Abstract: A method has been developed for the extraction of rhenium/VII/ with methylene blue. Nitrobenzene was found to be the most effective extractant for Re/VII/. The stoichiometry of metal to reagent determined by the method of substoichiometric extraction and slope-ratio method was found to be 1∶1.