Showing papers on "Nitrobenzene published in 1978"

Photochemical Oxidation of Benzene, Toluene, and Ethylbenzene Initiated by OH Radicals in the Gas Phase

Abstract: Photochemical oxidation of benzene, toluene, and ethylbenzene initiated by OH radicals in the presence of NO and NO2 was studied in the air by using a 67 dm3 reaction chamber made of Pyrex glass. OH radicals were produced by photochemical decomposition of nitrous acid, the products being phenol and nitrobenzene for benzene; cresols, benzaldehyde, m- and p-nitrotoluenes, and benzyl nitrate for toluene; ethylphenols, benzaldehyde, acetophenone, and m- and p-nitroethylbenzene for ethylbenzene. The reaction mechanisms are proposed based on the addition of OH radicals to aromatic rings and the hydrogen abstraction of OH radicals from alkyl groups.

Solvated electron reactions in water--alcohol solutions

Abstract: Rate constants for solvated electron reactions with oxygen, hydrogen peroxide, benzoquinone, nitrobenzene, and iodine in aqueous binary solutions of methanol and ethanol were determined by pulse radiolysis. The measured rate constants were used in conjunction with known diffusion coefficients to calculate reaction radii from the Debye--Smoluchowski equation. The calculated radii for the electron--oxygen reaction are found to be independent of the water--alcohol ratio for both solvent systems. The radii for the electron reaction with hydrogen peroxide show a similar behavior. For electron reactions with nitrobenzene, benzoquinone, iodine, and carbon tetrachloride the reaction radii increase with the increasing alcohol content in the solution, while the sums of diffusion coefficients of the reactants decrease. A correction for tunneling is suggested to explain the large reaction radii (6 to 15 A) for solvated electron reactions with several effective solutes. 1 figure; 3 tables; 24 references.

Effect of organic additives on micellar systems studied by positron annihilation techniques

Abstract: The rate constants for the reactions of positronium with nitrobenzene and cupric chloride in various aqueous micellar systems, such as sodium dodecylsulfate, hexadecyltrimethylammonium bromide, sodium octylsulfonate, hexadecylpyridinium chloride, and Tergitol-NPX, were measured in the presence of organic additives, such as benzene, benzyl alcohol, n-hexane, and 1-hexanol. The results show that the positronium reactivity toward nitrobenzene or cupric chloride substantially increases, when benzene or benzyl alcohol are added to sodium dodecylsulfate, hexadecyltrimethylammonium bromide, and hexadecylpyridinium chloride solutions, whereas only a slight increase was observed in Tergitol-NPX and no increase in sodium octylsulfonate solutions. In the former systems the rate constants are generally higher in the presence of benzene or benzyl alcohol than in aqueous solutions of nitrobenzene or cupric chloride and approach in the case of nitrobenzene values obtained for positronium reactions with nitrobenzene in benzene solution, whereas n-hexane or 1-hexanol generally exhibit only a small effect. A possible explanation for the observed behavior may be that the aromatic additives become incorporated into the micelle, possibly close to the micelle-water interface where they form clusters or aggregates in which the nitrobenzene probe molecules resides. In this benzene-like microenvironment the nitrobenzene molecule exhibits the same reactivity toward positronium as in benzene solutions.more » By the same token in the case of n-hexane or 1-hexanol additives, the corresponding rates slightly decrease with additive concentration and approach rate constants observed in a n-hexane-like environment. It appears that the positron annihilation technique can provide a sensitive method of studying the microenvironment of probe molecules in micellar systems.« less

Emulsified fuel composition and surfactant useful therein

Abstract: An emulsified fuel composition comprising fuel oil, water, and a surfactant. The surfactant comprises nitrobenzene, benzene, a fatty monocarboxylic acid, an alkylene oxide condensate, and a hydrocarbon oil.

Infrared study of the adsorption of anisoles on silica immersed in heptane

Abstract: Infrared spectra have been reported of silica immersed in solutions of anisole, six substituted anisoles (4-nitro, 4-chloro, 4-bromo, 4-methyl, 2-fluoro and 2,6-dimethyl), nitrobenzene and 4-nitrotoluene in heptane. Surface silanol groups were perturbed by hydrogen bonding interactions with either methoxy-groups or the benzene nuclei of adsorbed anisole molecules. Electron with drawing substituents in the anisole ring weakened both types of interaction. The proportion of perturbed silanol groups involved in interactions with benzene nuclei decreased with increasing electron withdrawing power of 4-substituents. Surface silanol groups formed hydrogen bonds with the nitro-groups of adsorbed nitrobenzene and 4-nitrotoluene molecules. An adsorptive interaction involving hydrogen-bond acceptance by nitro-group probably also occurred for 4-nitroanisole.

Process for producing aniline with a permselective palladium and ruthenium catalyst

Abstract: A process for producing aniline, residing in a catalytic hydrogenation of nitrobenzene by using hydrogen in a gaseous phase at a temperature of from 20° to 260° C. and under atmospheric pressure, using a membrane catalyst which is essentially an alloy of palladium and ruthenium taken in a mass percent ratio of 88-98:12-2, respectively, permselective to hydrogen; hydrogenation being carried out by feeding nitrobenzene on the one side of the membrane catalyst and hydrogen, on the other side thereof. The process enables one to obviate purification of the end product from the residual catalyst and thereby to avoid losses of metals of the platinum group, as well as to effect hydrogenation under milder conditions without the formation of any by-products.

Process for preparing p-aminophenol in the presence of dimethyldodecylamine sulfate

Abstract: The preparation of p-aminophenol by the catalytic hydrogenation of nitrobenzene in an acid reaction medium containing an aqueous isopropyl alcohol solution of trimethyldodecylammonium chloride leads to the formation of chloro- and isopropoxyaniline impurities These end up in the by-product aniline The substitution of dimethyldodecylamine sulfate for the quaternary salt eliminates these impurities without significant adverse effect on the yield, production rate or purity of the p-aminophenol

Ready hydrogenation of nitrobenzene and benzonitrile with a polymer-bound palladium catalyst

Abstract: A polymer-bound catalyst has been discovered which provides the first example of hydrogenation of nitro and nitrile functional groups with a PdII catalyst.

2,4,5-Trichlorophenol process

Abstract: A method of making 2,4,5-trichlorophenol by chlorinating 2,5-dichlorophenol is characterized by reacting 2,5-dichlorophenol with chlorine in the presence of a liquid inert polar aprotic reaction medium such as nitrobenzene or a chlorinated hydrocarbon reaction medium, particularly 1,2-dichloroethane, and preferable a Lewis acid catalyst, particularly aluminium chloride. The product contains a higher ratio of 2,4,5-trichlorophenol to 2,3,6-trichlorophenol than has been obtainable previously.

Para-aminophenol derivatives

Abstract: A process for the preparation of diaryl para-phenylenediamines from a crude para-aminophenol solution such as obtained by the catalytic hydrogenation of nitrobenzene in an aqueous acid reaction medium The process comprises contacting the para-aminophenol containing acidic solution, after neutralization with ammonia, with an aromatic amine selected from the group consisting of aniline, mixed toluidines, ortho-toluidine, mixed xylidines, and mixtures thereof under conditions whereby the aromatic amine extracts the para-aminophenol from the crude feed solution and is separated therefrom The separated solution comprised essentially of the aromatic amine extractant, para-aminophenol, and minor amounts of impurities is then contacted with an alkylation catalyst to produce the diaryl para-phenylenediamines

Preparation of substituted diphenyl ether

Abstract: PURPOSE: To obtain the title compound useful as pesticides, medicines and functional high polymer materials, in high yield and purity, by reacting a substituted nitrobenzene in the presence of an alkali metal salt or hydroxide in an organic polar solvent under relatively mild conditions. CONSTITUTION: One mole of a compound of formula I (X is halogen, trihalomethyl, cyano, acyl, carbamoyl, nitro group, etc.; n is an integer 1W5) is reacted in the presence of 1W10 equivalents of an alkali metal salt or hydroxide, e.g. Na 2 CO 3 or NaOH, in an organic aprotic polar solvent, e.g. DMF, at 60W200°C for 30 minW 30 hr to give the objective compound of formula II. EFFECT: High yield due to little by-product and slight discoloration because of the low reaction temperature. COPYRIGHT: (C)1980,JPO&Japio

The production of hydroxamic acid metabolites of nitrosobenzene by Chlorella pyrenoidosa.

Abstract: The ability of the green alga Chlorella pyrenoidosa to convert nitrosobenzene (I), phenylhydroxylamine (VI), aniline, and nitrobenzene to hydroxamic acid metabolites was investigated. Only nitrosobenzene and phenylhydroxylamine were partially converted to N-phenylacetohydroxamic acid (Va) and N-phenylglycolhydroxamic acid (Vb), with the latter compound being the major product. The possible mechanisms for the formation of these hydroxamic acid metabolites are discussed. The most plausible explanation for their production is through the interaction of the nitroso group with certain intermediates of thiamine-dependent enzymes. The conversion of phenylhydroxylamine to the hydroxamic acids probably is the result of initial oxidation to nitrosobenzene. Apparently, C. pyrenoidosa lacks nitroreductase and aniline hydroxylase activities, since no metabolic conversions of aniline or nitrobenzene were observed. The potential environmental significance of hydroxamic acid production from nitrosoaromatics is discussed.

Positrons bound to nitrobenzene molecules

Abstract: The time spectrum of positrons annihilated in benzene, in nitrobenzene and in their solutions was analysed. The main results attained through the measurements of the intensity and of the decay rate of the various components, as a function of the concentration, as well as through a magnetic-quenching experiment are the following: i) orthopositronium in benzene is localized in two regions differently exposed to the action of quenching and inhibiting agents, ii) the nitrobenzene molecule captures a positron giving rise to a bound system whose lifetime in nitrobenzene is τ = (0.395 ± 0.005) ns.

Novel technique for reacting vinyl cyclohexene with nitrobenzene in the presence of a hydrogen-transfer catalyst

Abstract: Vinyl cyclohexene is reacted with nitrobenzene to produce ethylbenzene, aniline, and styrene at 170° C.-360° C. in the presence of a hydrogen transfer catalyst typified by palladium acetylacetonate optionally containing cobalt acetylacetonate or copper oxide.

Studies on the reduction of nitrobenzene to aniline catalysed by pd(acac)2‐pyridine system

Abstract: The complex, bis(acetylacetonato)palladium(II) in pyridine, is used as a homogeneous catalyst for the conversion of nitrobenzene to aniline. From a study of various operational parameters the optimum reduction was found to occur at 1 atm pressure and at room temperature in petroleum ether (b.p. 100–120°C) solvent, yielding 90% of aniline on input nitrobenzene basis. The complex [Pd11(acac)H(C6H5NO2)Py] was isolated under similar experimental conditions and was characterised by elemental analysis, magnetic, thermal and spectral studies. Formation of a phenylnitrene metal complex has been suggested as a hypothetical intermediate in the reduction process.

Process for producing a linear trimer of paraisopropenyl phenol

Abstract: A novel trimer of p-isopropenyl phenol of the structure ##STR1## which is useful as a material or a curing agent for epoxy resins. The linear trimer includes a cis-isomer (m.p. 225.5°-227° C.) and a trans-isomer (m.p. 167°-168° C.). It is prepared by reacting p-isopropenyl phenol or its linear polymer in the presence of an acid catalyst such as sulfuric acid, boron fluoride or activated clay in an aromatic hydrocarbon, halogenated hydrocarbon, substituted aromatic hydrocarbon or aprotic polar solvent (e.g., benzene, carbon tetrachloride, nitrobenzene or dioxane).

Novel process for preparing aniline by catalytic reaction of vinyl cyclohexene and nitrobenzene

Abstract: A nitrohydrocarbon, typified by nitrobenzene, is reacted with a hydrocarbon such as 4-vinyl-1-cyclohexene at 70° C.-360° C. and 0-500 psig to give product stream containing aniline, ethylbenzene, and styrene; heterogeneous catalyst contains Group VIII noble metal, Group I B metal and optionally Group VI B metal, typically 0.5% platinum and 5% cuprous oxide on gamma alumina.

Chemistry of sulphenates in acidic media

Abstract: Methyl toluene-p-sulphenate is hydrolysed rapidly in moist solvents (dioxan, benzene, chloroform, or nitrobenzene) yielding methyl toluene-p-sulphinate, di-p-tolyl disulphide, and methanol. The reaction is acid catalysed. At higher concentration of water (>1%) the products are: p-tolyl toluene-p-thiolsulphonate, di-p-tolyl disulphide, and methanol. A mechanism is suggested where thiolsulphinate, which is usually suggested as the intermediate in the hydrolysis of sulphenyl derivatives, combines with unchanged sulphenate ester to yield an intermediate sulphonium salt. The sulphonium slat then rapidly reacts with either methanol or water to yield the products. Some implications for the chemistry of sulphenic acids are also discussed.

Preparation of urethane

Abstract: PURPOSE: To prepare the title compound useful as a raw material of polyurethane, in high yield, by reacting an aromatic nitro compound with an organic OH-containing compound in the presence of Se- or Se-compound catalyst, a base and hydrogen gas. CONSTITUTION: A urethane is prepared by reacting an aromatic nitro compound (e.g. nitrobenzene) with an organic OH-containing compound (e.g. monohydric alcohol, such as methanol, ethanol, etc.) and CO (atmospheric pressure to 200 kg/cm 2 G) in the presence of a catalyst comprising Se or Se compound (e.g. Se, SeO 2 , etc.), a base (e.g. Li acetate, Na acetate) and H 2 , pref. at 120W200°C. EFFECT: Urethane can be obtained in high yield even by recycling and reusing the catalyst. COPYRIGHT: (C)1979,JPO&Japio

Gas Phase Photochemical Reactions of Nitrogen Dioxide. Effect of Oxygen on the Conversion of Benzene into Nitrobenzene

Abstract: Gas phase photochemical nitration of benzene with nitrogen dioxide in the presence of oxygen was studied. Conversion of benzene into nitrobenzene was drastically accelerated by oxygen.

Process for producing pentachloro-nitrobenzene

Abstract: An improvement is disclosed in the preparation of pentachloronitrobenzene by the nitration of pentachlorobenzene. The improvement, which is primarily aimed at reducing the residual level of the undesirable starting material, pentachlorobenzene, in the product, includes a two-stage reactant mixing step wherein the pentachlorobenzene is first mixed with sulfuric acid and then concentrated nitric acid is added to this mixture.

Radical gas-phase decomposition of nitrobenzene derivatives

Abstract: 1. Kinetic characteristics for C-N bond rupture, the first elementary step in gas-phase decomposition, have been estimated for 13 derivatives of nitrobenzene. 2. A correlation equation relating molecular structures and rate constants has been developed for p- and m-derivatives with donor-type substituents.