Aklylation of benzene and toluene with C3–C12 alkenes in presence of aluminum

Conclusions In presence of aluminum activated with heptyl bromide, benzene and toluene are alkylated by alkenes at 50–80° with formation of monoalkylarenes in yields of up to 80%.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1244–1247, July, 1966.     

Quantitative Generalization of Solvent Effect on Radical Halogenation of Hydrocarbons

The dependences of the isomer ratio in photochemical chlorination of 2,3-dimethylbutane and of the selectivity in photochemical bromination of a mixture of cyclopropylbenzene and toluene may be described by linear multiparameter equations. In the first case, the determining factors are the nonspecific solvation power and molar volume of the solvent, and in the second, the molar volume and cohesion energy density.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 7, 2005, pp. 967–972.Original Russian Text Copyright © 2005 by Makitra, Midyana, Pal’chikova.     

Spectroscopic characterization of environmentally relevant C10-chloroterpenes from a photochemically modified toxaphene standard

Twenty-five pure environmentally relevant toxaphene components have been isolated from photochemically modified technical toxaphene by means of a combination of column chromatography on silica gel and preparative high resolution liquid chromatography. These compounds are 6 chlorinated camphenes (1–3, 5, 7, and 11) and 19 chlorinated bornanes (4, 6, 8–10, 12–16, 18–24, 26, and 27 according to Table 1). Two further chlorobornanes (17 and 25) have been isolated from a highly chlorinated mixture obtained by the excess chlorination of 2-exo,10-dichlorobornane. The structural elucidation of the isolated compounds has been carried out with spectroscopical methods.     

Isothermal vapor–liquid equilibria for binary mixtures of benzene, toluene, m-xylene, and N-methylformamide at 333.15 K and 353.15 K

Isothermal vapor–liquid equilibrium (VLE) at 333.15 K and 353.15 K for four binary mixtures of benzene + toluene, benzene + N-methylformamide, toluene + m-xylene and toluene + N-methylformamide have been obtained at pressures ranged from 0 kPa to 101.3 kPa. The NRTL, UNIQUAC and Wilson activity coefficient models have been employed to correlate experimental pressures and liquid mole fractions. The non-ideal behavior of the vapor phase has been considered by using the Soave–Redlich–Kwong equation of state in calculating the vapor mole fraction. Liquid and vapor densities were also measured by using two vibrating tube densitometers. The P–x–y diagram and the activity coefficient indicate that two mixtures of benzene + toluene and toluene + m-xylene were close to the ideal solution. However, two mixtures containing N-methylformamide present a large positive deviation from the ideal solution. The excess Gibbs energy in the benzene + toluene mixture is negative indicates that it is an exothermic system.     

Allylic chlorination of isoprenoid oligoolefins by sulfuryl chloride

Conclusions An efficient method has been proposed for the allylic chlorination of the terminal unit of linear isoprenoid oligoolefins using SO₂Cl₂ Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 2423–2424, October, 1988.     

Study of processes of interaction of aromatic compounds with the surface of manganese oxide catalyst

The scheme of the oxidative transformations of toluene, ethyl- and propylbenzene, and styrene during their chemisorption from a helium-oxygen mixture on the surface of a hydrated manganese dioxide under precatalysis conditions has been experimentally substantiated. These reactions lead to the formation of benzoate (toluene) or benzoate and formate (ethyl-, propylbenezene, styrene) structures on the surface.L. V. Pisarzhevskii Institute of Physical Chemistry. Ukrainian Academy of Sciences, Kiev. Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 27, No. 5, pp. 541–548, September–October, 1991. Original article submitted June 21, 1991.     

Solvent Extraction Separation of Th(IV) and U(VI) with PC-88A

Liquid-liquid extraction of Th(IV) and U(VI) has been investigated by commercial extractant PC-88A in toluene. The optimum conditions for extraction of these metals have been established by studying the various parameters like acid concentration/pH, reagent concentration, diluents and shaking time. The extraction of Th(IV) was found to be quantitative with 0.1–1.0M HNO₃ acid and in the pH range 1.0–4.0 while U(VI) was completely extracted in the pH range 1.0–3.5 with 2.5·10^–2M and 2.·10^–2M PC-88A in toluene, respectively. The probable extracted species have been ascertained by log D-log C plot as ThR₄·4HR and UO₂R₂·2HR, respectively. The method permits separation of Th(IV) and U(VI) from associated metals with a recovery of 99.0%.     

Synthesis and Cytotoxicity of Derivatives of Di(3-indolyl) Selenide

A method has been developed for the synthesis of di(3-indolyl) selenides. From indole and SeO₂. N-Alkyl derivatives of di(3-indolyl) selenide have been obtained in the two-phase system alkyl halide–solid K₂CO₃ (or KOH)–18-crown-6–toluene. It was discovered that N-unsubstituted di(3-indolyl) selenides possess high cytotoxicity on HT-1080 and MG-22A tumor cell lines.     

Membrane catalysts for hydrogenation with cryochemically synthesized palladium clusters

New type of membrane catalysts has been prepared through blinding of 2–3 µm pores of cermet membranes with Pd clusters from its cryochemically synthesized sol in toluene. Those catalysts display 30 times superior activity with respect to Pd weight than the membrane catalysts in the form of foil from Pd alloys.     

Nonuniqueness of solution of reverse problem of chemical kinetics for first-order reactions

The question of nonuniqueness of the solution of the reverse problem of chemical kinetics has been investigated. The subject of investigation is the situation in which some of the substances participating in the reaction are not accessible for measurement (intermediate substances). The investigation was performed on models of first-order reactions, using Laplace transforms. Direct mathematical formulas have been derived, through which an answer can be obtained to the question of how many independent functional combinations of constants, and which combinations, and will specifically admit an unambiguous evaluation on the basis of kinetic information on the initial reactants and the reaction products. The reaction of ethylene chlorination is examined as an illustrative example.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 21, No. 6, pp. 701–708, November–December, 1985.     

Multiresidue-matrix solid-phase dispersion method for determining 16 organochlorine pesticides and polychlorinated biphenyls in fish

Summary An effective, multiresidue-matrix, solid-phase dispersion — extraction (MSPD) and GC-MS method for the determination of 16 organochlorine pesticides (OCPs), as well as polychlorinated biphenyls (PCBs) from the level chlorination in fish is described. The method uses an octadecylsilyl-derivatized silica and Florisil-based MSPD co-column for direct, on-line clean-up. Recoveries calculated from five different fortification levels are >85% in all cases for OCPs, except for heptachlor and 4,4-DDT where recoveries of 78% and 81% are ob-tained, and >95% for PCBs. Detection limits determined for the OCPs vary from 19.6–91.1 ng g^–1, and from 71.4–111.2 ng g^–1 for the two to five chlorine-containing PCBs. The method has been applied to the analysis of fish grown in Er-Jen river (Taiwan) and method may serve as a screening protocol for the determination of OCPs and PCBs in fish.     

Separation of fluoride ion by extraction with triphenyltin chloride. Application for NAA of fluorine by means of 14-MeV neutrons

The separation of fluoride by extraction with toluene solution of triphenyltin chloride has been studied. Quantitative isolation of fluoride from solutions with a wide acidity range (pH 4.0–11.5) has been established. It is suggested that interferences by Ca, Mg, Fe, and Al can be avoided by masking these elements using sulfate and hydroxyde ions. Interference by phosphate ions can be overcome in a similar fashion. The halogenated species can be masked by mercury nitrate. Detection limit for fluorine determination is about 3 g for a neutron generator flux of 2·11¹¹ n·cm^–1·s^–1. A method for fluorine assay in water using a neutron generator with a detection limit of 1 ppm has been developed.     

Alkylaromatic carbene ions on H-TsVK zeolites

Conclusions The adsorption of styrene (298 K), triphenylcarbinol (298 K), and of propylene with toluene (473 K) on H-TsVK zeolite leads to the formation of alkylaromatic carbocations which are stable up to 473–573 K and are characterized by bands in DRS at 320–330 and 400–440 nm and in IR by vC=C of the aromatic ring in the regions 1500 and 1610–1620 cm^–1. In the adsorption of benzene, toluene, isopropylbenzene, and 1,3-dimethylnaphthalene at 298 K, only weakly bonded surface complexes are formed.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1486–1490, July, 1989.     

The effect of Fe2O3 dopants on electrophysical and sorption properties of ZnO

The effect of Fe₂O₃ dopants (0–0.8 mol.%) on ZnO conductivity and its chlorine chemisorption ability has been studied in the temperature range of 20–250 °C. Introduction of dopants increases the activation energy of ZnO conductivity and decreases the conductivity. The effective charge of the chemisorbed chlorine species as well as the strength of their bonding to the surface in samples containing Fe₂O₃ are considerably lower than in initial ZnO, which leads to a decrease of reactivity of the doped catalysts in chlorination.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1196–1199, July, 1993.     

The role of the N- and C-terminal amino acids of activated peptide esters in their polycondensation

Summary 1. The polycondensation of activated esters of some dipeptides has been studied. The dependence of M_av on the time has been established.2. It has been shown that the degree of polycondensation of the polypeptides depends on the nature of the N- and C-terminal amino acids of the activated ester of the peptide and of the monomer.Lenin Tadzhik State University. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 502–506, July–August, 1974.     

Chlorine derivatives of octaorganylsilasesquioxanes

The chlorination of saturated and unsaturated octaorganylsilasesquioxanes proceeds through two pathways, leading to the formation of volatile and nonvolatile products, whose ratio depends on the reaction conditions. The volatile products of the chlorination of R-T₈ (R=C₂H₅ and CH=CH₂) are compounds with the general formula Cl_nR_8–n[SiO_1.5]₈, (n=1–7), obtained independently of the nature of the organic substituent and chlorinating agent. The nonvolatile chlorination products are silasesquioxanes, containing chlorine and chloroalkyl substituents on the atoms of the silicon-oxgyen core. Analysis of the vibrational spectral data indicated that the most significant changes in the molecular vibrational system are made by the halogenation of the silicon-oxygen core Si₈O₁₂.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 446–450, February, 1990.     

Synthesis and Solid-State Conformation of a Calix[8]arene 1,5-Diquinone Derivative

The first example of a calix[8]quinone derivative, hexamethoxy-p-tert-butylcalix[8]-1,5-diquinone 5, has been synthesized from p-tert-butylcalix[8]arene 1by exploiting a protection-deprotection procedure. The structure of the 5·toluene inclusion compound has been determined by a single crystal X-ray diffraction study. The calix[8]arene molecule possesses a crystallographic inversion centre and assumes a ‘pseudo-chair-like’ conformation, with two opposite 3/4-cone moieties, which resembles the previously reported chair-like conformation of p-tert-butylcalix[8]arene. The 4 toluene molecules per unit cell occupy interstitial voids and are released in the temperature range of 30–160 °C.This revised version was published online in July 2005 with a corrected issue number.     

Kinetics of the gas-phase chlorination of activated carbon with carbon tetrachloride

The chlorination of activated charcoals KAU and SCN with CCl₄ vapor in the temperature range 300–600 °C and also the thermal stability of the added chlorine has been studied. It is shown that chlorination with CCl₄ vapor led to the addition of up to 22 mass % (6.2 mmol/g) of chlorine to the surface layer of the carbon. The added chlorine is desorbed from the surface with formation of HCl, while at temperatures above 500 °C desorption of chlorine goes practically to completion. The effective rate constants and the energies of activation of the processes of chlorination and desorption have been found.     

Field determination of iodide in water

A simple, fast and sensitive spectrophotometric method for the quantification of iodine and iodide in waters is described. Firstly iodide has been oxidised by sodium nitrite to iodine in HCl medium and the resulting I₂Cl^– has been preconcentrated into toluene. This can be subsequently determined in the extract with brilliant green. A ten-fold preconcentration is obtained, the molar absorptivity is (4.2×10⁴) I mol^–1 cm^–1 at 635 nm. A detection limit of 4 ng/ml iodide in water can be reached. The effect of common anions and cations have been investigated. The method has been applied to the determination fo free iodine, total iodine and iodide in river, pond and well water.     

Certain aspects of heterophase ion exchange

Ion exchange between an aqueous solution of KCl and a solution of tetraoctylammonium bromide in toluene has been studied at 20–70°C. Equilibrium exchange constants were measured. The free energy of the ion exchange is determined to a large extent by Coulombic interaction, which increases with decrease in the radius of the ion. The strength of the Q⁺X^– bond is weakened on passing from the normal onium salt to the hydrate and the rate of ion exchange increases. The position of equilibrium during approach to it from different sides may be affected by different formation processes of complexes with low activity in respect to exchange.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1773–1776, August, 1991.