Showing papers on "Nitrobenzene published in 1986"

On the mechanism of transfer of sodium ion across the nitrobenzene/water interface facilitated by dibenzo-18-crown-6

Abstract: The question of the site of ionophore–ion complex formation, whether it is in the organic phase (EC), in the aqueous phase (CE), or at the interface (E), in the transfer facilitated by dibenzo-18-crown-6 of sodium ion across the nitrobenzene/water interface was studied by kinetic analysis of the ion transfer using a.c. polarographic method. The results indicate that the interface reaction mechanism (E) is the most probable of the three.

Liquid-phase hydrogenation of nitrobenzene in a slurry reactor

Abstract: This article deals with studies of the liquid-phase hydrogenation of nitrobenzene to aniline in a discontinuous laboratory-scale stirred reactor with suspended Ni catalyst. The influence of temperature, pressure, nitrobenzene concentration and pH value on the reaction rate was investigated. Apart from the kinetics, a series of technically relevant effects which are not covered by the kinetic model are studied. A rate equation of the Langmuir—Hinshelwood type was selected on the basis of the reaction scheme and the experimental data. The kinetic model was examined by checking with the experimental data in an agitated reactor and in an industrial reactor.

Process for the production of nitrobenzene

Abstract: In the production of nitrobenzene by subjecting benzene to nitration with a mixture of nitric acid and sulfuric acid, separating off the nitrobenzene formed, concentrating the sulfuric acid by evaporation and returning the concentrated sulfuric acid to the bezene nitration stage, the improvement which comprises concentrating sulfuric acid to a concentration of from 75 to 92% by evaporation in vacuo at temperatures in the range from 130° to 195° C. Thereby the energy per kg of water evaporated is drastically reduced compared to processes wherein the sulfuric acid is concentrated to a higher level, without a corresponding loss in efficiency or capacity.

Vapor-phase nitration of benzene over polyorganosiloxanes bearing sulfo groups

Abstract: Polyorganosiloxanes with sulfo groups have the high catalytic activity for vapor-phase nitration of benzene. The polysiloxane with sulfophenyl groups showed the highest activity. The reaction rate depended greatly on the partial pressures of both benzene and nitrogen dioxide. The nitrobenzene yield of 80% was obtained at 443 K under the partial pressures of benzene and nitrogen dioxide of 20 and 40 kPa, respectively.

Polycondensation of squaric acid with N-alkylcarbazoles

Abstract: 1,2-Dihydroxycyclobutene-3,4-dione (squaric acid) was polycondensed with N-ethyl- and N-(1-butyl)carbazole in polyphosphoric acid to give polymers having 36–43% of 1,2-oriented squarate units. The polymers are insoluble in organic solvents or sulfuric acid. Condensation of 1,2-dichlorocyclobutene-3,4-dione (squaryl dichloride) with N-1-butyl-carbazole in nitrobenzene gave 100% of 1,2-oriented squarate units. This polymer is soluble in most organic solvents, and the molecular weight (¯Mw) is 1900 (DP=6). The electrical conductivity was low, <10−9 (ohm cm)−1, and did not increase on treatment with iodine.

Production of carboxylic acid from aqueous solution of ammonium carboxylate

Abstract: PURPOSE: In producing the titled compound useful as a raw material for various higher esters by heating an aqueous solution of ammonium carboxylate, to improve yield advantageously by the use of thermal decomposition distillation, by adding an organic solvent capable of extracting a carboxylic acid to the aqueous solution of ammonium carboxylate. CONSTITUTION: An aqueous solution of ammonium carboxylate is thermally decomposed in an organic solvent (e.g., acetophenone, mesityl oxide, octyl aldehyde, trioctylamine, nitrobenzene, etc., especially preferably ketone, etc.) capable of extracting a carboxylic acid at 70W120°C, ammonia is distilled away and removed out of the system, the carboxylic acid is extracted with an organic solvent phase, and the aimed compound is recovered from the organic solvent phase. When ammonium acrylate or ammonium methacrylate is used as the ammonium carboxylate and subjected to thermal decomposition distillation, addition of polymerization inhibitor is required, and an amount added is preferably 0.01W0.5wt%. COPYRIGHT: (C)1986,JPO&Japio

Europium and cerium extraction by the nitrobenzene solution of dicarbolide in the presence of polyethylene glycols

Abstract: Extraction a partir d'acide perchlorique. Extraction sous forme ML 3+ , ML 2 3+ , ML 3 3+ , MLH −1 2+ (L=polyethylene oxyde)

Raman spectroscopic observation of adsorbates on Ag during electrochemical reduction of nitrobenzene

Abstract: Raman spectroscopic observation of the surface of a silver electrode during potentiostatic reduction of nitrobenzene in neutral and alkaline aqueous solutions has revealed adsorption of at least four chemical species at different potentials. At –0.5 V (vs. SCE), where the reduction starts, trans-azobenzene was detected with two other species. Raman bands of adsorbed aniline were observed at more cathodic potentials. When aniline was adsorbed from its aqueous solution, three of the above four species except azobenzene were detected on the electrode. Adsorbed aniline lies flat on the surface.

3,3'-dimethylbenzidine derivative

Abstract: NEW MATERIAL:A compound of formula I (R1, R2 are H, lower alkyl, lower alkoxy, Cl). USE:A photoconductive material which is used for electrophotography. It can provide a photosensitive substance with high flexibility and sensitivity. It can be sensitized optically or chemically using a sensitizing agent such as a dye or Lewis acid. PREPARATION:The reaction between 3,3'-dimethylbenzidine of formula II and a compound of formula III (X is I, Br) is carried out in the presence of a copper powder, copper oxide or copper halide and a base such as sodium hydroxide and potassium carbonate, when needed, in a solvent such as nitrobenzene at 150-250 deg.C to give the compound of formula I.

Relationship between physical parameters of the solvent and its influence in stereocomplex formation

Abstract: An extensive study on the influence of the solvent on the PMMA stereocomplex formation was made by means of laser light scattering and viscometry for the following solvents: nitroethane, cyclohexanone, aniline, 1,1,2,2-tetrachloroethane, ethyl benzoate, 1,2-dimethoxyethane, N,N-dimethylacetamide, ethyl and propyl acetate, ethyl methyl and isobutyl methyl ketone, 1,2-dichloroethane, 1,4-dioxane, DMF, bromoform, chloroform, chlorobenzene, 1,2-dichlorobenzene, 1,3-dichlorobenzene, 1,1,1-trichloroethane, and trans-1,2-dichloroethane. It was found that a variation in the polymer tacticity causes a change in the influence of the solvents on stereocomplex formation, e.g. in the case of chlorobenzene, 1,2-dichlorobenzene and nitrobenzene. Further, the influence of the solvent was related with the non-polar, polar and hydrogen bonding components of the solubility parameter, δd, δp and δh.

Titrations in non-aqueous media. Part I. Determination of factors influencing the basicity of schiff bases in nitrobenzene solvent

Abstract: Potentiometric titrations of Schiff bases with perchloric acid in nitrobenzene solvent were carried out in order to obtain information about the factors that influence the basicities of the Schiff bases. The Schiff bases were synthesised from aromatic aldehydes and amines bearing an aromatic ring. Some contained a methylene group between the aromatic ring and the imino group and others contained a hydroxy group ortho to the imino group. For each Schiff base, an S-shaped potentiometric titration curve was obtained. From these curves half-neutralisation potentials were determined and from the latter the pKa′ values. In these determinations the half-neutralisation potential of 0.001 M hexa(p-toluidino)cyclotriphosphazatriene [N3P3(NH-p-tol)6] in nitrobenzene with perchloric acid was taken as the standard.

Reduction of nitroarenes to anilines in basic alcoholic media

Abstract: Substituted nitrobenzenes are reduced by alkoxide ions in alcohols to the corresponding azoxy and aniline derivatives. The reaction leading to anilines has been investigated in detail. Two different processes have been identified, both initiated by the condensation between the nitrosoarene intermediate (the first product of the reduction reaction) and the product of oxidation of the solvent. The imino derivative thus formed (ArNCH–COR) may either undergo hydrolysis (to aniline) or form, through a series of redox processes, compounds containing the ArNH–CO moiety. These are also hydrolysed to anilines in a slower reaction.

Isotopic enrichment by electron exchange

Abstract: The importance of isotope separation has increased due to the wide use of isotopes in both energy- and life-science-oriented applications1 This, coupled with our observation2 that the solution electron affinities3 of perdeuterated hydrocarbons are less than those of corresponding undeuterated species, led us to investigate the possibility of isotopic enrichment through electron exchange equilibria Here we report the observation that nitrobenzene containing 15N has a higher affinity for solvated electrons in liquid ammonia than does nitrobenzene containing the most common isotope of nitrogen (14N) When an equal-molar mixture of 14N-nitrobenzene (PhNO2-14N) and 15N-substituted nitrobenzene (PhNO2-15N) is added to a solution of solvated electrons in liquid ammonia, the anion radical of PhNO2−15N is formed predominantly over that of PhNO2-14N Furthermore, as the chemical and physical properties of the resulting anion radicals (PhNO2-15N− and PhNO2-14N−) are very different from those of the neutral molecules, the electron exchange equilibrium between these two isotopic species can be utilized to enrich samples selectively with respect to the two isotopic species Analogous results have been observed for the case of benzophenone-12C and benzophenone-13C (carbonyl 13C)

A Time-Resolved ESR Study on the Photochemical Reduction of Nitrobenzene Derivatives in Alcoholic Solution

Abstract: Time-resolved ESR experiments have been carried out to elucidate the initial process in the photochemical reduction of aromatic nitro compounds The first observation of CIDEP due to nitrobenzene anion radicals in the presence of an electron donor proved that radical generation takes place through a triplet mechanism

Titrations in non-aqueous media. Part III. Basicity order of aniline, N-Alkyl- and N-aryl-substituted anilines and pyridine in nitrobenzene solvent

Abstract: The relative basicity order of ammonia, pyridine, aniline and N-methyl-, N,N-dimethyl-, N-ethyl-, N,N-diethyl-, N-aryl- and N,N-diaryl-substituted anilines have been determined potentiometrically with perchloric acid in nitrobenzene solvent and found to be NH3 > Py > PhNEt2 > PhNMe2 > PhNHEt > PhNHMe > PhNH2 > Ph2NH > Ph3N. This order in general conflicts with the results observed by other workers in either the gas phase or in the condensed phase. N-Alkyl substitution increases the basicity of the aniline, and N-aryl substitution decreases its basicity. Moreover, the number and size of the substituent influence the basicity of aniline. N-Ethyl-substituted anilines are more basic than the corresponding N-methyl-substituted anilines. The position of pyridine in the order is surprising and difficult to interpret.

A 14C Balance on Nitrobenzene Oxidized Kenaf Lignin

Abstract: Kenaf, containing unlabeled or 14C-labeled lignin was oxidized by nitrobenzene. Reaction products were separated, the 14C-content measured, and the products identified by mass spectroscopy (MS) and high pressure liquid chromatography (HPLC). Principal products and their approximate percentage of “original-lignin-14C-content” were: syringaldehyde 20%, oxalic acid 20%, high-molecular-weight species 16%, vanillin 8.2%, benzoic acid and 4-hydroxy-azobenzene 10.7%, neutral species 3% or less, syringic acid 2.4%, vanillic acid 1.5%, and malic acid (trace). Numerous aromatic products at about the 1% concentration level remain unidentified.

Production of modified polycyclic aromatic condensate and its resin

Abstract: PURPOSE: To obtain the title condensate which can economically give a modified polycyclic aromatic resin excellent in moldability and heat resistance, by using a polycyclic aromatic hydrocarbon, formaldehyde and a specified aromatic compound as starting materials and condensing these materials in two stages. CONSTITUTION: A polycyclic aromatic hydrocarbon (e.g., naphthalene or anthracene oil) is condensed with formaldehyde or a formaldehyde-generating substance (e.g., methylal) in the presence of an acid catalyst (e.g., a Lewis acid) in a polar organic compound (e.g., nitrobenzene) as the solvent. A modified polycyclic aromatic condensate can be obtained by condensing the obtained primary condensate with an aromatic compound of the formula (wherein Ar is an aromatic hydrocarbon, X is an acidic group and n is 1W4), e.g., α,α'-dihydroxy-p-xylene. A modified polycyclic aromatic resin can be obtained by curing this condensate by heating. COPYRIGHT: (C)1988,JPO&Japio