Showing papers on "Nitrobenzene published in 1992"

Hydration of complexes of some univalent cations with polyethylene glycol ligands in nitrobenzene saturated with water

Abstract: The hydration numbers of the complexes ML + formed by some univalent cations (M + = Li + , Na + , NH 4 + , K + , Rb + and Cs + ) and polyethylene glycol ligands (L = PEG 200, PEG 300 and PEG 400) in nitrobenzene saturated with water were determined. The highest differences between the hydration numbers of the cations M + and the complexes ML + were found in the systems with the Na + cation.

Membrane solvent extraction removal of priority organic pollutants from aqueous waste streams

Abstract: A recently developed nondispersive microporous membrane-beed solvent extraction technique has been used to remove a number of priority organic pollutants simultaneously from a synthetic high strengh aqueous waste stream. A microporous hydrophobic hollow fiber based membrane extractor having an order of magnitude higher contact area than conventional extraction devices he been used. The pollutants were phenol, 2-chlorophenol, nitrobenzene, toluene, andacrylonitrile. The extracting solvents were methyl isobutyl ketone (MIBK), isopropyl acetate (IPAc), and hexane

Unusual behavior of 5,10,15,20-tetraphenylporphine diacid toward oxygen Broensted bases

Abstract: Acid-base properties of 5,10,15,20-tetraphenylporphine diacid salts (H 4 TPP 2+ (X - ) 2 ) in the presence of neutral oxygen Bronsted bases have been studied in chloroform and nitrobenzene by visible and 1 H-NMR spectroscopy. The acid strength and the conformation of H 4 TPP 2+ (X - ) 2 are largely determined by the size and the nature of the counterion X -

Complex Formation of Hydronium Ion with Several Crown Ethers in 1,2-Dichloroethane, Acetonitrile, and Nitrobenzene Solutions

Abstract: A conductance study concerning the interaction between hydronium ion and several crown ethers in acetonitrile, nitrobenzene and 1,2-dichloroethane solutions has been carried out at 25°C. The stability constants of the resulting 1:1 complexes in acetonitrile and nitrobenzene solutions were determined from the molar conductance-mole ratio data and found to vary in the order 18C6>DB30C10>DC18C6>DB18C6>DB21C7>DB24C8>B15C5. In 1,2-dichloroethane solution, the complexation process results in the dissociation of ion pairs. There is an inverse relationship between the stabilities of the complexes and the Gutmann donicity of the solvents. In nitrobenzene solution, some evidence for the formation of a 2:1 sandwich adduct between the smaller crowns (i.e., B15C5 and 18-crowns) are observed from the molar conductance-mole ratio data which is supported by the1H NMR data.

Diffusion and sorption of organic liquids through polymer membranes. VIII: Elastomers versus monocyclic aromatic liquids

Abstract: Sorption and diffusion of five monocyclic aromatic liquids—three halogenated benzenes, nitrobenzene, and aniline—with five engineering polymers—ethylene propylene diene ter-polymer, nitrile butadiene rubber, styrene butadiene rubber, natural rubber, and neoprene—have been investigated in the temperature interval of 25–60°C. Solvent diffusivity into polymer membranes was determined from the immersion/weight gain experiments. Permeability coefficients were also calculated from the diffusion and sorption data. A temperature dependence of sorption and transport was also investigated to estimate the activation parameters. The experimental results and computed quantities were used to study the type of transport mechanism and the nature of polymer-solvent interactions.

Catalytic oxidation and oxidative dehydrogenation using metal-compound-loaded, deboronated hams-1b crystalline borosilicate molecular sieve compositions

Abstract: Compositions comprising certain metal-containing materials distributed interactively on a deboronated HAMS-1B crystalline borosilicate molecular sieve which are useful for catalytically oxidizing or oxidatively dehydrogenating organic compounds such as alkanes, aromatics, and alkyl-substituted aromatics are described. Alkanes are oxidatively dehydrogenated to olefins, and an aromatic compound such as benzene can be oxidized by nitric and/or nitrous oxide to largely phenol or largely nitrobenzene depending upon the oxidation temperature. When the compound is a methylaromatic, oxidation produces an aromatic aldehyde. Alkyl groups larger than methyl oxidatively dehydrogenate to alkenyl groups. The compositions can be used in a process to separate p-xylene from a mixture of its isomers based upon the ability of the compositions, which preferably comprise a iron molybdenum material interactively distributed on a deboronated HAMS-1B crystalline borosilicate molecular sieve, to selectively oxidize the p-xylene to an aldehyde or dialdehyde while not substantially oxidizing the ortho and metaxylene isomers. Such partially oxidized mixtures of p-xylene are useful to make TPAA or as feeds to a water-based, further oxidation to make terephthalic acid. Carbon dioxide used as a carrier gas with a methylaromatic feed to the oxidation catalyst is shown to have a beneficial effect on yield and selectivity.

Synthesis of poly(2,5-dialkoxyphenylene)

Abstract: Poly(2,5-dibutoxyphenylene) with inherent viscosities up to 0.92 dL.g -1 . was prepared by oxidative coupling polymerization of 1,4-dialkoxybenzene. in nitrobenzene in the presence of FeCl 3 at room temperature. The effects of various factors, such as amount of solvent and FeCl 3 and reaction temperature were studied. The polymer was estimated to consist of almost equal fractions of 1,4- and 1,3-linkages. It was soluble in common organic solvents and could be processed into uniform films from solution. The polymer showed 10% weight loss at 385°C in both air and nitrogen

Breakdown of waste waters containing aromatic nitro compounds

Abstract: A process for breaking down aromatic nitro compounds in waste waters from plants for the production of nitrobenzene by treatment with nitric acid is carried out at from 180° to 350° C. and under a pressure of from 40 to 250 bar.

Experimental determination of the electron affinities of nitrobenzene, nitrotoluenes, pentafluoronitrobenzene, and isotopic nitrobenzenes and azulenes

Abstract: The absolute electron affinities of nitrobenzene, m-, o-, and p-nitrotoluene, pentafluoronitrobenzene, deuterated nitrobenzene, 15 N-substituted nitrobenzene, azulene, and deuterated azulene have been determined by measuring the temperature dependence of the response of the electron capture detector (ECD). These are the first ECD determinations of the absolute electron affinities of these compounds and the only values of the electron affinities of the isotopically substituted compounds

Concentration Dependence of Surface Diffusivity of Nitrobenzene and Benzonitrile in Liquid Phase Adsorption onto an Activated Carbon

Abstract: Batch kinetic experiments were performed for adsorption of nitrobenzene and benzonitrile from aqueous solution onto activated carbon, the isotherms of which were only partially expressed by Freundlich equations. The experiments were carried out with adsorbents which had been equilibrated with a certain concentration of the solution in advance, to obtain adsorption rates representing certain ranges of the amount adsorbed. The intraparticle mass transfer rate was confirmed to be dominated by surface diffusion through the determination of pore diffusivity using a non-adsorptive substance, while the external mass transfer resistance could not be neglected

Mössbauer spectroscopic investigation of the sorption of iron by polyether-type polyurethane-foam sorbents

Abstract: The results of a study on the nature of the iron species sorbed by polyether-type open-cell polyurethane (PU) foam membranes are presented. The study has included freshly prepared anionic 57FeIII–halo complexes and 57Fe(SCN)3, in addition to the cationic 57FeII–phenanthroline complex. Conclusions concerning the most probable nature of the sorbed species have been drawn from the comparison of Mossbauer spectra for frozen Fe—PU foam complexes with the spectra for corresponding iron-containing frozen aqueous solutions and extracts in suitable organic solvents. For FeIII compounds, diethyl ether, and for the FeII complex, acetone, pentyl alcohol and nitrobenzene were used as organic solvents. The spectra were recorded at 80 K and evaluated to obtain isomer shifts, quadrupole splittings and internal magnetic fields for different iron species.

Efficient Six-Electron Photoreduction of Nitrobenzene Derivatives by 10-Methyl-9,10-dihydroacridine in the Presence of Perchloric Acid

Abstract: Photoreduction of nitrobenzene derivatives by 10-methyl-9,10-dihydroacridine (AcrH2) occurs efficiently in the presence of perchloric acid in acetonitrile containing H2O (0.50 mol dm−3) to yield the corresponding six-electron reduced products (aniline derivatives) and 10-methylacridinium ion efficiently. The initial two-electron reduction of PhNO2 to PhNO by AcrH2 in the six-electron reduction of nitrobenzene (PhNO2) is started by electron transfer from AcrH2 to the n,π* triplet state (3PhNO2*), followed by acid-catalyzed thermal reduction of PhNO to PhNHOH by AcrH2 and the subsequent photoreduction of PhNHOH to PhNH2 by AcrH2.

Synthesis of aromatic polyethers by Scholl reaction. VI. Aromatic polyethers by cation-radical polymerization of 4,4'-, 3,3'-, and 2,2'-bis(1-naphthoxy)biphenyls and of 1,3-bis(1-naphthoxy)benzene

Abstract: Aromatic polyethers with molecular weights M n up to 90500 g/mol are prepared by the cation-radical polymerization of bis-(1-naphtyloxy)aryls in nitrobenzene with FeCl 3 as oxidant.

Process for 3-exomethylenecepham sulfoxide esters

Abstract: 3-Exomethylenecepham sulfoxide esters are obtained in improved yields via cyclization of 3-methyl-2-(4-chlorosulfinyl-2-oxo-3-amino-1-azetidinyl)-3-butenoic acid esters under anhydrous conditions with a Lewis acid-type Friedel-Crafts catalyst in the presence of a nitro compound, e.g., nitromethane, nitroethane, nitropropane or nitrobenzene.

Extraction and transport of sodium ion and potassium ion in a liquid membrane containing crown ethers: effect of the mixed solvent

Abstract: Transport rates for K + and Na + have been measured in a bulk liquid membrane containing dibenzo-18-crown-6 as the carrier and employing chloroform, 1,2-dichloroethane, nitrobenzene, and their binary solutions as the solvent. Also distribution ratios for liquid-liquid extraction of K + and Na + from aqueous solutions into organic solvents containing the crown ether are prepared

Enthalpies of solution of naphthalene, N,N-dimethyl-1-naphthylamine, and 1,8-bis(dimethylamino)naphthalene in 16 organic solvents

Abstract: The enthalpies of solution of naphthalene, N,N-dimethyl-1-naphthylamine, and 1,8-bis(dimethylamino)naphthalene (proton sponge) were determined at 298.15 K in 16 organic solvents (n-hexane, cyclohexane, carbon tetrachloride, chloroform, 1,2-dichloroethane, benzene, chlorobenzene, dimethyl sulfoxide, N,N-dimethylformamide, ethyl acetate, 1,4-dioxane, anisole, nitrobenzene, benzonitrile, methanol, ethanol). Additional determinations were made with benzene. Useful linear relationships are observed between the molar enthalpies of solution of the four compounds in the solvents. The molar enthalpies of solution were correlated with the solvatochromic parameter of the solvents. The presence of N(CH3)2 groups on naphthalene does not significantly contribute to the solute–solvent interactions.

Effect of Components of Based Catalytic System on Reductive Carbonylation of Nitrobenzene

Abstract: A three component catalytic system consisting of (i) elemental sulfur or sulfur compounds (CS 2 , H 2 S, COS), (ii) an alkali methoxide or triethylamine, and (iii) vanadium(V) compounds (V 2 O 5 , NH 4 VO 3 ) has been applied as catalyst for reductive carbonylation of nitrobenzene to methyl N-phenyl carbamate with carbon monoxide and methanol at a temperature of 423 ± 2 K and an initial carbon monoxide pressure of 10-14 MPa/298 K. The efficiency of sulfur compounds increased in the sequence S:CS 2 :H 2 S:COS = 1:1.6:7.9:13.8. Hydrogen sulfide decreased however the selectivity of the reaction to the carbamate and increased that to aniline. Formation of the latter amine is increased especially in the presence of water in the reaction mixture and of hydrogen in the synthesis gas above 40 vol.%. The efficiency of the bases decreased in order CH 3 OK > CH 3 ONa = NaOH > (C 2 H 5 ) 3 N and of vanadium compounds in the sequence NH 4 VO 3 > V 2 O 5 . The catalyst system thus allows to effect the reductive carbonylation of aromatic nitro compounds in the absence of transition metal compounds.