Showing papers on "Nitrobenzene published in 1969"

Studies of the Interaction between the Hexyl Anion and Alkali Metal Ions

Abstract: The Hexyl(2,4,6,2′,4′,6′-hexanitrodiphenylamine) anion forms ion-pairs with alkali metal cations to some extent in an aqueous solution. The association constants of these ion-pairs were determined both in nitrobenzene by conductivity measurements and in water by the solvent extraction method. The association constants in nitrobenzene (KoMR) decrease in the following order: Li>Na>K>Rb>Cs. The plot of log KoMR against the ionic potential of the alkali metal ions was found to be linear. In nitrobenzene saturated with water, however, the constants vary from 2 to 4. In water the asscoiation constants (KaMr) vary from about 10 to 400, and the value increases as follows: Li

Reduction of nitro- and nitroso-compounds by tervalent phosphorus reagents. Part IV. Mechanistic aspects of the reduction of 2,4,6-trimethyl-2′-nitrobiphenyl, 2-nitrobiphenyl, and nitrobenzene

Abstract: Reduction of 2′,4′,6′-trimethyl-2-nitrobiphenyl by triethyl phosphite gives 2-amino-2′,4′,6′-trimethylbiphenyl and triethyl N-(2′,4′,6′-trimethylbiphenyl-2-yl)phosphorimidate. The same reduction, carried out in cumene or in t-butylbenzene gives, additionally, 8,10-dimethylphenanthridine, and, in cumene, 2,3-dimethyl-2,3-diphenyl-butane, indicating the intermediacy of a triplet nitrene. Reduction of nitrobenzene by diethyl methylphosphonite in an excess of diethylamine gives 2-diethylamino-3H-azepine (83%), while the corresponding reaction with 2-nitrobiphenyl gives 2-diethylamino-3-phenyl-3H-azepine (13%) in addition to carbazole (63%), pointing to an intermediate similar to that present in decompositions of azides, i.e. a nitrene or nitrenoid species, the nature of which is discussed.The order of reducing reactivity of a series of tervalent phosphorus reagents towards 2-nitrobiphenyl is (EtO)2PMe (Et2N)3P ∼(EtO)P(NEt2)2 > (EtO)3P ∼(PriO)3P ⋙ PCl3(inactive).

Salting-in and salting-out of polar nonelectrolytes

Abstract: The solubility of toluene and benzaldehyde was measured in NaBr and (n-Pr)4NBr aqueous solutions at 25 °C, and the solubility of benzoic acid and nitrobenzene was measured in the same systems at 10...

Study of the Mechanism of Electroadsorption at the Water-Nitrobenzene Interface

Abstract: When an electric field is applied between two solutions of octadecyl trimethyl ammonium bromide in water and in nitrobenzene in partition equilibrium, modifications in the interfacial tension can be observed. From the law of variation of these modifications as a function of time, Blank proposed to explain this effect by an accumulation of matter due to the difference in the transport numbers of the ions in the two media of the salt used. It is shown, by direct measurement, that there is in fact accumulation of matter in the water in the vicinity of the interface. Besides, when octadecyl trimethyl ammonium picrate is employed, very large variations in the interfacial tension are observed although its ions have the same transport number in each medium. Because of the behavior of the curve (interfacial tension-applied potential) it does not seem possible to explain the phenomenon by electrocapillary adsorption, a hypothesis suggested by Blank, when the material studied is hardly soluble in one of the two media.

Photolysis of Nitrosobenzene

Abstract: The mechanism of the photochemical reaction of nitrosobenzene (I) has been investigated. The irradiation of I leads to the formation of a phenyl radical and nitric oxide. The reaction of the phenyl radical with I yields diphenylnitroxide, which is then easily reduced to diphenylamine. The reaction of diphenylamine with the nitric oxide gives C-nitrosodiphenylamines, which are then photochemically oxidized to C-nitrodiphenylamines. On the other hand, I is oxidized to nitrobenzene and is, at the same time, reduced to azoxybenzene and azobenzene. Azoxybenzene is photochemically rearranged to 2-hydroxyazobenzene.

Oxidation of hydrazine derivatives. Part I. Oxidation of phenyl-hydrazine with lead tetra-acetate

Abstract: The oxidation of phenylhydrazine with lead tetra-acetate in the solvents benzene, chlorobenzene, nitrobenzene, and dichloromethane has been investigated. At low temperatures in dichloromethane the benzenediazonium ion was formed. At room temperature, benzene, azobenzene, biphenyl, and, where aromatic solvents were used, biaryls, were isolated and identified. The formation of these products can be explained in terms of the formation of phenyldi-imide and its subsequent homolytic and heterolytic breakdown.

Reduction of nitro- and nitroso-compounds by tervalent phosphorus reagents. Part V. Reduction of alkyl- and methoxy-nitrobenzenes, and nitrobenzene by trialkyl phosphites

Abstract: Reactions of triethyl- and trimethyl-phosphites with o-, m-, and p-nitrotoluene, o- and p-ethylnitrobenzene, o- and p-nitroanisole, and nitrobenzene give the corresponding dialkyl N-arylphosphoramidates, and dialkyl N-alkyl-N-arylphosphoramidates, and, in some cases, trialkyl N-arylphosphorimidates, the probable precursors of the above amidates. In some cases low (⩽18%) yields of dialkyl alkyl-3H-azepin-7-ylphosphonates are formed, indicating the intermediacy of nitrenoid species. Reaction of triethyl phosphite with p-ethyl-, p-methyl-, and p-methoxynitrobenzenes, and of trimethyl phosphite with o-nitroanisole and p-nitrotoluene give low yields of the corresponding dialkyl arylphosphonates, representing the first recorded instances of displacement of a simple aromatic nitrogroup unactivated by either electronic influences or special steric factors.

Selenium tetrafluoride adducts. I. Trifluoroselenium fluorosulfate

Abstract: The structure of the adduct between selenium tetrafluoride and sulfur trioxide in the solid state, in the molten state, and in solution has been investigated using infrared, Raman, nuclear magnetic resonance spectroscopy, conductivity measurements in fluorosulfuric acid and nitrobenzene, and cryoscopic measurements in nitrobenzene. The data can be best interpreted in terms of a polymeric bridged fluorosulfate structure for the solid and the melt, which is broken down in solution to form mainly a dimeric species.

Field distribution in nitrobenzene using the Kerr effect

Abstract: Electric field distributions have been measured in nitrobenzene using the Kerr electro-optical effect. Both metal and composite electrodes have been used to investigate their charge-injection properties. From the field-distribution measurements it has been shown that positive injection readily occurs when two metal electrodes are used with a space charge near the cathode. When two dissimilar electrodes are used (composite and metal), injection from the composite electrode is always suppressed in comparison with the injection from the metal electrode, this phenomenon being independent of polarity. From the space-charge thickness, estimates of mobility are 1·33 cm2v−1s−1 for the positive carriers and 0·28 cm2v−1s−1 for the negative carriers.

Thermodynamic Properties of the Solvent Extraction of Anions with TRIS(1,10-Phenanthroline)iron(II) Chelate Cations

Abstract: Thermodynamic quantities were determined for the extraction of ion pairs of tris(1,10-phenanthroline) iron(II) chelate cations with halide, thiocyanate and perchlorate anions from aqueous phase into nitrobenzene. Ion pairs with larger anions have more negative enthalpy changes with higher extractability. For bromide, the enthalpy change was found to be almost zero and a positive change was observed for chloride. Entropy changes are also discussed.

Electrical conductivity studies of fluorosulfuric acid and tetramethylammonium fluorosulfate in nitrobenzene

Abstract: Electrical conductivity data for solutions of tetramethylammonium fluorosulfate and fluorosulfuric acid in nitrobenzene are reported. The dissociation constant of the tetramethylammonium salt is 2....

Some reactions of the nitrobenzene radical-anion and of its halogenated derivatives

Abstract: A technique for preparing and handling stable solutions of the nitrobenzene radical-anion, (PhNo2·)–, in dry methyl cyanide is described. The first-order decay of this radical in the presence of a small percentage of an aqueous buffer is ascribed to the diffusion-controlled rate of neutralisation of the anion.E.s.r. measurements show that the electron-transfer reactions of (PhNO2·)– with quinones, diketones, and aromatic nitro-compounds of higher oxidation potential than nitrobenzene are rapid. The anions of ortho-chlorinated nitrobenzenes are unstable and undergo a first-order decay in which the labile chlorine is replaced by hydrogen.

Cyclo- and Cyclized Diene Polymers. XXI. Polymerization of Isoprene by Stable Carbonium Ion Salt Catalysts

Abstract: The cyclopolymerization of isoprene was readily effected with the stable carbonium ion salts C7H7 +SbCl6 − and (C6H5)3C+SbCl6 − in nitrobenzene. Little or no polymerization occurred when n-heptane, benzene, toluene, acetonitrile, methylene chloride, or nitromethane were used as reaction media. The molecular weights of the polymers obtained by light-scattering were in the range of 6,000–70,000 although the intrinsic viscosities in benzene were extremely low, i.e., 0.03–0.06. Triphenylmethyl groups were detected in cyclopolyisoprene prepared with (C6H5)3C+SbCl6 − as catalyst. No tropylium residues were detected in polymers prepared with C7H7 +SbCl6 −. All polymers contained 10–45% unsaturation (trans-1,4 and 3,4). The unsaturation decreased with increasing trityl ion concentration but was independent of tropylium ton concentration. At constant isoprene concentration, a limiting conversion was reached; polymerization resumed on the addition of monomer. SbCl5 in nitrobenzene was an effective catalyst...

Catalytic process for epoxidation of olefinic compounds in the presence of molecular oxygen

Abstract: 1,216,645. Epoxides. INSTITUT FRANCAIS DU PETROLE DES CARBURANTS ET LUBRIFIANTS. 12 Sept., 1969 [16 Sept., 1968], No. 45081/69. Heading C2C. An aliphatic or cycloaliphatic olefin is epoxidized by treating in the liquid phase with molecular oxygen at 20-250‹ C. under an oxygen partial pressure between 0A05 and 60 kg./cm. 2 , in the presence of a catalyst comprising molybdenum, tungsten or vanadium or a compound thereof deposited on a zeolite, the pores of which have an opening diameter between 6 and 10S, the molybdenum, tungsten or vanadium content of the catalyst being between 0A02 and 20% by weight with respect to the weight of the carrier and the catalyst being used in an amount of from 10 -1 to 10 -3 gram-atom of metal per kilogram of feedstock. If desired a solvent may be used and suitable solvents are, for example, benzene, chlorobenzene, o-dichlorobenzene, diphenyl, nitrobenzene, phenyl oxide, phenyl polyoxides, or esters, e.g. of acetic, benzoic, phthalic, isophthalic, terephthalic acids or of various trialkyl acetic acids, alcohols, glycols, and ketones.

Polymers with quinoxaline units. V. Polymers with quinoxaline and dioxin units

Abstract: Ladder or partly ladder polymers have been prepared by condensation of tetraphenols with tetrachloroquinoxaline compounds in melt, or in pyridine, naphthalene, and nitrobenzene reaction media. The polymers are dark-colored, powdery materials with good thermal stability. Some of the samples are slightly soluble in sulfuric acid, while others are completely insoluble. No other solvents were found.

Effect of solvent mixtures on the ν(CO) bands of some metal carbonyl complexes

Abstract: The ν(CO) spectra of Mo(CO)4 bipy (bipy = 2,2′-bipyridyl), cis-[W(CO)2{o-C6H4(PEt2)2}2],Cr(CO)3(π-mesitylene), and Cr(CO)3(π-C6H5·CO2Me) are examined in solution in n-hexane–chloroform or –nitrobenzene mixtures; the ν(NO) spectrum of Fe(NO)(S2CNMe2)2 is studied in benzene–nitromethane mixtures. Structure observed on the ν(CO) bands is discussed in terms of formation of solvent–solute complexes.

Erratum A CINDO CI study of the electronic structure and spectrum of nitrobenzene

Abstract: The electronic spectrum of nitrobenzene is investigated by means of the modified CNDO method of Del Bene and Jaffe.

Aspects of the metallic halide-catalysed reaction of Grignard reagents with organic halides. Part II. Effect of variation in reactants

Abstract: An investigation has been carried out of variation in reactants for the metal halide-catalysed reaction of Grignard reagents with organic halides in the presence of monosubstituted benzene derivatives as diluting solvents. With bromobenzene as halide, variation in Grignard reagent, in solvent for Grignard, in metalic halide catalyst, and in potential intermediate catalysts derived from metallic halides, produced no change in the ratio of isomeric biphenyls formed except when the Grignard reagent was prepared in the absence of ethereal solvent. In this case the ratio of isomeric biphenyls was more comparable with that found when benzoyl peroxide is the source of the phenyl radical. This suggests that the reduction in ortho-substitution and concomitant increase in meta-substitution found when ethereal Grignard reagents are used, may be due to formation of complexes of phenyl radicals with solvent ether. The chlorides of cobalt, iron, and nickel are suitable catalysts, but those of copper and samarium are inactive. The evidence points to the metal derived from the catalyst as the ‘active catalyst’, rather than a metallic sub-halide or organometallic species. Use of nitrobenzene as the aromatic solvent gave azoxybenzene as a major neutral product, and hence nitrobenzene cannot be used as a solvent for competitive reactions which use this source of phenyl radicals. The results of competitive reactions between t-butylbenzene and bromobenzene and chlorobenzene support the view that phenyl radicals participate in these reactions.

Radical intermediates. Part I. Spectroscopic studies on the alkali-metal nitrobenzenides

Abstract: Alkali-metal derivatives of the nitrobenzene radical anion have been prepared as stable solids, and their e.s.r. and u.v. spectra interpreted in terms of the radical and its decay products. Solutions of the radical show remarkable stability in a wide range of solvents including water. The e.s.r. spectra of such solutions indicate that significant amounts of tightly bound ion pairs are present in solvents such as acetonitrile and acetone even at radical concentrations of around 10–4M.

Effect of nitrobenzene in the styrene–cellulose acetate graft polymerization system

Abstract: The effect of nitrobenzene, a polymerization retarder, upon the direct γ-ray-induced graft polymerization of styrene onto pyridine-swollen cellulose acetate film was studied. When the films were not highly swollen, small nitrobenzene additions caused an increase in the amount of grafted polystyrene and grafted cellulose acetate. However, when the substrate was highly swollen, nitrobenzene additions reduced the amount of grafted polystyrene without pronounced changes in the amount of grafted cellulose acetate. The number-average molecular weights of the grafted side chains were always two to three times those of the homopolystyrene formed in the bulk monomer solution, which is indicative of hindered chain termination within the substrate film under all reaction conditions. Nitrobenzene additions prevented polystyrene crosslinking reactions, probably because the termination reactions in the presence of nitrobenzene occur by disproportionation rather than by coupling of chain ends. Viscometric results indicated that the polystyrene side chains were branched.