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[Display omitted] • Metal-free C H thioarylation. • Using hexachloroethane as a stable, cheap, available and safe solid for sulfenylation. • No need for dimethyl sulfoxide. • Providing a safer alternative to methods that rely on toxic and unstable oxidants. A metal-free and one-pot procedure for thioarylation of uracils and in situ generated enaminones with thiols in the presence of C 2 Cl 6 is introduced. This protocol is a less toxic alternative to other conventional thioarylation techniques because it uses hexachloroethane as a solid oxidant, which is stable, inexpensive, readily available and easier to work with. [ABSTRACT FROM AUTHOR]

In this work the electrochemical degradation of polychlorinated compounds using Co(dmgH)2Cl(py), Co(dpgH)2Cl(py), Co(chgH)2Cl(py) and Co(dbegH)2Cl(py) (where dmgH is dimethylglyoximato, dpgH is diphenylglyoximato, chgH is 1,2-cyclohexanedionedioximato and dbegH is 4,4'-((1E,2E)-1,2-bis(hydroxyimino)ethane-1,2-diyl)dibenzoate) is described. The degradation was studied using cyclic voltammetry by monitoring current changes in the zone near to the Co(II/I) half wave potential as the concentration of the organochloride in the electrochemical cell is increased. Hexachloroethane (HCA) was used as organohalide substrate, while gamma-hexachlorocyclohexane (lindane), 1,2-dichloroethane, and 1,1,1-trichloroethane were used for comparative studies. The major dechlorination product of HCA, detected through head space GC-MS experiments after bulk electrolysis, was tetrachlorethylene. The rate constants of the dechlorination processes were estimated using the foot-of-the-wave analysis (FOWA), the values obtained were 1.10x105, 2.59x104, 4.91x104 and 1.83x104 for Co(dmgH)2Cl(py), Co(dpgH)2Cl(py), Co(chgH)2Cl(py) and Co(dpegH)2Cl(py) respectively. [ABSTRACT FROM AUTHOR]

The degradation mechanism of the pollutant hexachloroethane (HCA) by a suspension of Pd-doped zerovalent iron microparticles (Pd-mZVI) in dissolved lactic acid polymers and oligomers (referred to as PLA) was investigated using gas chromatography and the indirect monitoring of iron corrosion by continuous measurements of pH, oxidation-reduction potential (ORP), and conductivity. The first experiments took place in the absence of HCA, to understand the evolution of the Pd-mZVI/PLA/H2O system. This showed that the evolution of pH, ORP, and conductivity is related to changes in solution chemistry due to iron corrosion and that the system is initially cathodically controlled by H+ mass transport to Pd surfaces because of the presence of an extensive PLA layer. We then investigated the effects of Pd-mZVI particles, temperature, initial HCA concentration, and PLA content on the Pd-mZVI/PLA/HCA/H2O system, to obtain a better understanding of the degradation mechanism. In all cases, HCA dechlorination first requires the production of atomic hydrogen H*—involving the accumulation of tetrachloroethylene (PCE) as an intermediate—before its subsequent reduction to non-chlorinated C2 and C4 compounds. The ratio between Pd-mZVI dosage, initial HCA concentration, and PLA content affects the rate of H* generation as well as the rate-determining step of the process. A pseudo-first-order equation can be applied when Pd-mZVI dosage is much higher than the theoretical stoichiometry (600 mg for [HCA]0 = 5-20 mg L−1). Our results indicate that the HCA degradation mechanism includes mass transfer, sorption, surface reaction with H*, and desorption of the product. [ABSTRACT FROM AUTHOR]

The vibrational spectra of hexachloroethane (HCE) were investigated between 10 and 1000 cm-1 in the temperature range from 40 to 360 K. The three phases are characterized. The spectra are interpreted with the help of a normal coordinate analysis and a calculation of the crystal dynamics. A mechanism of the phase transition is proposed. [ABSTRACT FROM AUTHOR]

Refinement of α-Mg solid solution grains has a significant influence on the improvement of mechanical properties of cast magnesium alloys. In the article, the effects of three modifiers on microstructure and properties of AZ91 magnesium alloy casted to a sand mould were described. Overheating, hexachloroethane and wax-CaF2-carbon powder were applied. The research procedure comprised microstructure analysis by means of light microscopy, scanning electron microscopy and quantitative analysis with AnalySIS Pro® software and mechanical properties’ investigation. The microstructure of AZ91 alloy in the as-cast condition consists of α-Mg solid solution with precipitates of Mg17Al12, Mg2Si and Al8Mn5 phases. It was reported that all applied modifiers cause refinement of α-Mg solid solution grains and a decrease of the volume fraction of α-Mg+Mg17Al12 compound discontinuous precipitates. The best results were obtained in the case of wax-CaF2-carbon powder.

The outdoor atmospheric distributions of chlorinated volatile organic compounds (VOCs) from locations receiving the emissions of a chlor-alkali plant have been studied. Trichloroethylene and tetrachloroethylene (medians 2.4 μg/m 3 and 1.7 μg/m 3 , respectively) were the most abundant compounds, which was in accordance with the production processes from these installations. The concentrations of trichlorofluoromethane, median 1.6 μg/m 3 , are rather similar to the average levels described in general in the troposphere and cannot be attributed to this specific source. Several by-products involving dichloroacetylene, carbon tetrachloride, hexachloroethane, hexachlorobutadiene, trans -1H-pentachloro-1,3-butadiene, 2H-pentachloro-1,3-butadiene, cis -1H-pentachloro-1,3-butadiene, tetrachloro- and trichloro-butadienes and hexachlorobenzene were also identified. Some of these compounds, e.g. carbon tetrachloride, chloroform and tetrachloroethane, could also have been manufactured during some periods. The occurrence of these manufactured compounds and by-products in the atmosphere could also reflect, at least in part, volatilization during the extraction of previously discharged chlor-alkali residues developed within the environmental restoration program of the Flix water reservoir. In this respect, the tri-, tetra- and pentachloro-1,3-butadienes could also originate from microbial transformation in the solid deposits accumulated in the water reservoir which were volatilized after extraction. Among all identified VOCs, trichloroethylene showed the highest health risks considering the measured airborne concentrations and the WHO and USEPA recommendations. [ABSTRACT FROM AUTHOR]

The degradation of hexachloroethane using chloridobis(dimethylglyoximato)pyridinecobalt(III), chloridobis(methylphenylglyoximato)pyridinecobalt(III) and chloridobis(diphenylglyoximato)pyridinecobalt(III) is described. To achieve the degradation, the cobalt complexes were reduced to the Co(I) oxidation state by electrochemical means. The chemical catalysis was studied using cyclic voltammetry by monitoring the current increase near the Co(II)/Co(I) reduction potential as the concentration of organohalogen was increased in solution. Tetrachloroethene was found as the degradation product. The apparent rate constant for the dehalogenation of hexachloroethane was estimated for all cobaloximes, obtaining 2.54 ± 0.08 × 10 5 for [Co(dmgH) 2 Cl(py)]; 2.38 ± 0.06 × 10 5 for [Co(mpgH) 2 Cl(py)] and 2.79 ± 0.15 × 10 5 for [Co(dpgH) 2 Cl(py)]. [ABSTRACT FROM AUTHOR]

Distortions of the directional requirements in halogen…halogen contacts between hexachloroethane (HCE), C2Cl6, molecules lead to a loose crystal under ambient conditions. Single-crystal X-ray diffraction shows that the orthorhombic HCE phase of space group Pnma, with the molecules in the staggered conformation, extends at least from 85 to 305 K and from 0.1 MPa to 5.42 GPa. At ambient pressure, all intermolecular distances are longer than the sum of van der Waals radii, reached only at the pressure of ca. 1.2 GPa. [ABSTRACT FROM AUTHOR]

The development and validation of a novel kinetic model for the chlorination of 1,2-dichloroethane to ultimately hexachloroethane catalyzed by blue light are presented. A factor ( X m) related to the chlorination depth was introduced into the kinetics model, and the results showed that the dynamic features of the photo-chlorination are better predicted by the modified model than by the conventional one. Furthermore, to enhance the selectivity towards tetrachloroethane and pentachloroethane, a novel reactive distillation with side-reactor configuration (SRC) for the photo-chlorination process was proposed. In order to demonstrate the technical feasibility of the process, semi-batch SRC experiments on the laboratory scale were carried out. Up to 96.5 wt % of tetrachloroethane and pentachloroethane with molar ratios varying from 7 to 0.7 over time were obtained in the bottom product. [ABSTRACT FROM AUTHOR]

The photocatalytic transformations of carbon tetrachloride and aliphatic primary alcohols in the presence of iron trichloride and a molar ratio of components FeCl3: CCl4: ROH = 1: 300: 2550 were studied. CCl4 is transformed into chloroform and hexachloroethane after exposure to a mercury lamp (250 W) to the FeCl3–CCl4–ROH system at 20°C, whereas the primary ROH alcohols are selectively oxidized into acetals (1,1-dialkoxyalkanes). The maximum conversion of CCl4 reaches 80%. The kinetics and mechanism of the photocatalytic conversion of the FeCl3–CCl4–ROH system are considered. [ABSTRACT FROM AUTHOR]

The solubilization of hexachlorobutadiene (HCBD) and hexachloroethane (HCA) in water as a function of temperature and in the presence of surfactants was investigated in order to predict their fate in groundwater and to increase their recovery. HCBD and HCA solubility data were experimentally determined at five temperatures in the range from (285.15 to 318.15) K. Thermodynamic parameters for dissolution (ΔsolG°, ΔsolH°, and ΔsolS°) have been calculated in order to propose a physical explanation of the minimum solubility observed between 293.15 and 298.15 K for both compounds. The solubilization process appeared to be influenced by the network of water molecules rather than by physical and chemical properties of HCBD or HCA, due to an opposite effect of temperature onto Brownian motion, which increases with temperature, and hydrogen-bond network, which collapses with temperature. Concerning the influence of surfactants, determination of the micelle–water partition coefficients (Kmw) and the molar solubilization ratio (MSR) has shown that the solubilization per micelle was more important for nonionic surfactants Triton X-100 and Tween 80 than for anionic SDBS. Also, the increase of solubility was 1 order of magnitude higher for liquid HCBD than for crystalline HCA irrespective of surfactant. [ABSTRACT FROM AUTHOR]

Traditional Fermi resonance is a vibrational mixing between a fundamental and a combinational or overtone mode. What will happen when the resonance occurs between a generated fundamental and an overtone mode? In this report, we performed a high pressure Raman spectroscopic investigation on hexachloroethane up to 20 GPa. The origin of the triple bands at 841, 851 and 860 cm −1 were thoroughly discussed, and their intensity evolution in the compression process are further analyzed. The triple bands can be attributed to the quantum mixing between generated v 7 fundamental mode and the v 2 overtone mode, This intriguing spectral phenomenon is named as double Fermi resonance, and a new mechanism of the interaction of double Fermi resonance is proposed. Pressure provides us a new strategy not only for the mode assignments but also to understand the mechanism underlying the vibrational mixing. [ABSTRACT FROM AUTHOR]

Context:Zinc chloride (ZnCl2)-based smoke bombs and screens are in use since the Second World War (1939–1945). Many case descriptions on ZnCl2smoke inhalation incidents appeared since 1945. Objective:We provide a comprehensive overview of the clinical symptoms and underlying pathophysiology due to exposure to fumes from ZnCl2smoke producing bombs. In addition, we give a historical overview of treatment regimens and their outcomes. Methodology:We performed a literature search on Medline, Scopus and Google Scholar databases using combinations of the following search terms “smoke bomb”, “smoke screen”, “ZnCl2”, “intoxication”, “poisoning”, “case report”, “HE smoke”, “hexachloroethane smoke”, “smoke inhalation” and “white smoke”. We retrieved additional reports based on the primary hits. We collected 30 case reports from the last seven decades encompassing 376 patients, 23 of whom died. Of all the patient descriptions, 31 were of sufficient detail for prudent analysis. Results and conclusions:Intoxication with clinical signs mainly took place in war situations and in military and fire emergency training sessions in enclosed spaces. Symptoms follow a biphasic course mainly characterised by dyspnoea, coughing and lacrimation, related to irritation of the airways in the first six hours, followed by reappearance of early signs complemented with inflammation related signs and tachycardia from 24 h onwards. Acute respiratory stress syndrome developed in severely affected individuals. Chest radiographs did not always correspond with clinical symptoms. Common therapy comprises corticosteroids, antibiotics and supplemental oxygen or positive pressure ventilation in 64% of the cases. Of the 31 patients included, eight died, three had permanent lung damage and 15 showed complete recovery, whereas in five patients outcome was not reported. Early signs likely relate to caustic reactions in the airway lining, whereas inhaled ZnCl2particles may trigger an inflammatory response and associated delayed fibrotic lung damage. Smoke bomb poisoning is a potentially lethal condition that can occur in large cohorts of victims simultaneously. [ABSTRACT FROM AUTHOR]

This work investigated the effect of hexachloroethane coated mould on the mechanical properties of hypoeutectic aluminium silicon alloy. An alumina based mould coating containing varying proportion (5% to 30%) of volatile hexachloroethane, C2Cl6 was prepared. The prepared mould coating was applied to form a coat of 2mm thick on the prepared metallic mould. The hypoeutectic aluminium-silicon alloy melted at 50°C superheat was poured into the already prepared coated mould and allowed to solidify. Then the effects of the volatile hexachloroethane, C2Cl6 concentration on the grain size, ultimate tensile strength (UTS), 0.2% Proof Stress, Hardness, percentage elongation and percentage reduction in area of the cast hypoeutectic aluminium-silicon alloy were assessed. The study revealed that the increase in C2Cl6 concentration in the mould coating up to 15 wt.% decreases the grain size of the alloy thereby causing increase in the mechanical properties (UTS), 0.2% proof stress, hardness, percentage elongation and percentage reduction in area) of the alloy. It was established that the optimum value of C2Cl6 concentration at which the mechanical properties were optimum is about 15 wt.%. Beyond this value, the C2Cl6 becomes deleterious to grain refinement due to rapid agitation in the mould.

Polyvinyl butyral films mixed with xylenol blue (XB) indicator and hexachloroethane (HCE) were prepared for possible application in food irradiation. Upon γ-irradiation the films undergo visual color change from yellow (XB, pH 8) to red (XB, pH 2.8) by H formation in the presence of HCE. The dosimetric characteristics of films containing different dye and HCE concentrations were investigated spectrophotometrically at λ 555 nm. Radiation sensitivity is enhanced with HCE and, accordingly red color intensity. The prepared films can be applicable in dose range 0.25-10 kGy with uncertainty of dose reaching 4.45 % at 1 σ. [ABSTRACT FROM AUTHOR]

Phospholenes containing one or two methyl groups at the 3 and 4 positions on the heterocyclic ring and bis(trimethylsilyl)amino groups on phosphorus were prepared by treating 1-bromo or 1-chlorophospholenes with lithium bis(trimethylsilyl)amide. Several P(V) derivatives of these 2-and 3-phospholenes were prepared by oxidation with hexachloroethane. The chloro groups in the resulting P-chloro-N-trimethylsilyl derivatives were subsequently replaced by phenoxy groups to afford P-phenoxy-N-trimethylsilyl substituted ring compounds. The P-phenoxy-N-trimethylsilyl derivative was hydrolyzed to the corresponding P-amino phosphine oxide; treated with trifluoroethanol to form a new trispirocyclic phosphazene; and copolymerized with Me2P(OPh) = NSiMe3to give a new phosphazene copolymer containing the phospholene ring (Mw= 3.8 × 104Da). These new compounds were characterized by1H,13C, and31P NMR spectroscopy. The spirocyclic phosphazene was also characterized by X-ray crystallography. [ABSTRACT FROM PUBLISHER]

The rate of chloropicrin removal and product formation when chloropicrin is exposed to simulated sunlight were determined in the absence and presence of oxygen. We observed phosgene and nitrosyl chloride as the products, which are produced after chloropicrin undergoes cleavage of the C–N bond to form carbon trichloride and nitrogen dioxide radicals. The observed rates are not strongly dependent on chloropicrin pressure but do vary with oxygen pressure, and the presence of oxygen clearly changed the mechanism of the reaction of the radical products. Under near-environmental pressures of oxygen, we estimate the environmental half-life of chloropicrin at 5.9 ± 1.5 h. [ABSTRACT FROM AUTHOR]

Negative ion formation through dissociative electron attachment to the gas-phase volatile anaesthetics enflurane and isoflurane (C 3 H 2 ClF 5 O) and to two chlorinated ethanes, pentachloroethane (C 2 HCl 5 ) and hexachloroethane (C 2 Cl 6 ), have been studied in a crossed electron-molecular beam two sector field mass spectrometer experiment. Anion efficiency curves for the negatively charged fragments have been measured over an electron energy range of approximately 0–17 eV, with an energy resolution of ∼1 eV. For the chlorinated ethanes, resonance features were generally found at ∼0 eV and at 7.5 eV. For the volatile anaesthetics, no zero energy resonances were observed. Instead, product anions were detected mainly in the 2–3 eV and 9 eV energy regions, with the exception of Cl − , whose dominant resonance occurs at approximately 0.6 eV and 0.9 eV for isoflurane and enflurane, respectively. To aid in the interpretation of the experimental results, quantum chemical calculations providing thermochemical thresholds of anion formation are also presented. [ABSTRACT FROM AUTHOR]

Dispersive liquid-liquid microextraction in combination with gas chromatographic-mass spectrometric determination is suggested for phenyltin compound analysis in aqueous solutions. The derivatization of the analytes with sodium tetraethylborate was carried out prior to the extraction. The effects of extraction and disperser solvent type, volume and extraction time on the extraction efficiency were investigated. Tetrachloromethane was used as an extraction solvent, ethanol was used as a disperser solvent, and hexachloroethane was used as an internal standard. The calibration graphs were linear from 46 ng l-1 (monophenyltin), 161 ng l-1 (diphenyltin) and 152 ng l-1 (triphenyltin) up to 1 mg l-1 (for all the analytes), correlation coefficients were 0.996-0.999, limits of detection were 14, 58 and 46 ng l-1 for monophenyltin, diphenyltin and triphenyltin, respectively. Repeatabilities of the results were 4.6-17.3%. A possibility to apply the proposed method for phenyltin compound determination in river water was demonstrated. [ABSTRACT FROM AUTHOR]

The treatment of Li2C(PPh2NMes)2 (1, Mes = 2,4,6-Me3C6H2) with hexachloroethane yielded the corresponding carbenoid 2 in good yields. The reactivity of 2 was studied with BH3·SMe2 to give a zwitterionic boronium species 4, also a stable carbenoid. Both carbenoid species were found to be excellent catalysts for the CO2 reduction by BH3·SMe2. [ABSTRACT FROM AUTHOR]

The iminophosphorane ( 3), obtained from reaction of ethyl 3-amino-4-cyano-1-phenyl-1 H-pyrrole-2-carboxylate ( 2) with triphenylphosphine, hexachloroethane, and triethylamine, reacted with aromatic isocyanates to give carbodiimides ( 4). Further reaction of 4 with various amines, phenols, or ROH to give 2,3,5,7-tetrasubstituted 3 H-pyrrolo[3,2- d]pyrimidine-4(5 H)-ones ( 6) in satisfactory yields in the presence of catalytic amount of sodium alkoxide or solid potassium carbonate. [ABSTRACT FROM AUTHOR]

Abstract: The main objective of this study was to test the capability of CNMs to mediate the reductive dechlorination of chlorinated aliphatic hydrocarbons. We herein investigated the mediation effects of graphene oxide (GO) and multi-walled carbon nanotubes (CNT) on the reductive dechlorination of hexachloroethane by sodium sulfide in aqueous solutions (pH buffered). The presence of 10mg/L CNT or GO enhanced the observed pseudo-first-order rate constant (k obs) of the reaction by a factor of 2 and 4, respectively; the enhancement effects were significantly greater than that of a soil humic acid (20mgC/L). The strong enhancement effects of the test CNMs were attributable to the facilitated electron transfer by the graphitic surfaces and particularly to the activation of C–Cl bonds of hexachloroethane by the zigzag carbon atoms at the edges and defects of the carbon nanomaterials. Additionally, changes of pH and the presence of dissolved humic acid could significantly affect the CNT- and GO-mediated reactions. The reaction rate was markedly accelerated by the increase of pH, but was suppressed by the coexisting dissolved humic acid. The findings imply that CNMs have the potential to enhance reductive dechlorination of relatively recalcitrant contaminants, such as chlorinated aliphatic hydrocarbons, in natural aquatic environments. [Copyright &y& Elsevier]

Abstract: A simple solid-state dechlorination route has been demonstrated to synthesize few layered functionalized carbon nanosheets (FCNS) utilizing hexachloroethane as carbon source and copper as reducing agent under the autogenic pressure at 300°C. The obtained FCNS possesses the sheet thickness of 6–12nm as analyzed by transmission electron microscopy. The particle nature of the FCNS provides the excess porosity having the surface area 836m2/g. The equilibrium gas adsorption study of FCNS for greenhouse gases (CO2 and CH4), toxic gas (CO) and light gas (N2) showed the maximum adsorption capacity for CO2 (2.95mmol/g; at 288K) with maximum capacity selectivity of 10.1 at 318K. The very strong adsorbate–adsorbent interaction was observed in case of CO compare to other gases resulted in higher heat of adsorption for CO. The gas adsorption and FT-IR study showed that the interaction of CO with copper present in minute quantities in FCNS improves the CO adsorption due to π complexation. The FCNS obtained under present methodology showed the very high equilibrium selectivity for CO over N2 (197) followed by CH4 (61) and CO2 (7.3) at 288K. [Copyright &y& Elsevier]

Abstract: We present a detailed study on the liquid structure of hexachloroethane (C2Cl6) within the first shell using the proper Euler-angles convention. Molecular dynamics is used and the van der Waals picture of a liquid is taken as the main phenomenology. Particular attention is paid to the first neighbor structure studying the distance of the center of mass (CM) and relative orientation arrangements. The distance dependence of the orientation and location of closer neighbors is studied up to the fourth neighbor (the maximum of first peak of the CM radial distribution function). An unusual arrangement in the first neighbor is seen. [Copyright &y& Elsevier]

In contrast to previous studies which employed zero-valent iron powder, this paper investigated reductive dechlorination of hexachloroethane (HCA) using iron shavings and bimetallic iron shavings modified with Cu, Ag, or Pd. Results clearly show that iron shavings offer superior reductive dechlorination of HCA. In addition, surface-normalized pseudo first-order dechlorination rates of 0.0073 L⋅m-2⋅h-1, 0.0136 L⋅m-2⋅h-1,0.0189 L⋅m-2⋅h-1, and 0.0084 L⋅m-2⋅h-1 were observed in the presence of iron shavings (Feº) and the bimetallic iron shavings Cu/Fe, Ag/Fe, and Pd/Fe, respectively. Bimetallic iron shavings consisting of Cu/Fe and Ag/Fe could greatly enhance the reductive reaction rate; Pd/Fe was used to achieve complete dechlorination of HCA within 5 hours. The additives of Ag and Pd shifted product distributions, and the reductive dechlorination of HCA occurred via β reductive elimination and sequential hydrogenolysis in the presence of all iron shavings. This study consequently designed a reaction pathway diagram which reflected the reaction pathway and most prevalent dechlorination products. Iron shavings are a common byproduct of mechanical processing plants. While the purity of such Fe metals may be low, these shavings are readily available at low costs and could potentially be used in engineering applications such as contamination control technologies. [ABSTRACT FROM AUTHOR]

A study of the synthesis of hollow carbon fibers by combustion route is presented. The synthesis was carried out using sodium azide and calcium carbide as reductants and hexachloroethane as oxidizer. The influence of several factors on the product morphology was investigated, including the catalyst precursor content, the ratio of organic/inorganic carbon precursor, the atmosphere in the autoclave and stoichiometry of the reactants. The developed route is simple and fast. It uses low-cost starting materials and does not require sophisticated equipment. [ABSTRACT FROM AUTHOR]

In part one of this work, it was shown that in addition to sodium formate, hexachloroethane (HCE) and perchloroethylene are the main products of the catalytic hydrodechlorination of CCl in a medium of sodium hydroxide solutions. These products undergo mutual transformations under the conditions of the process. Since the industrial requirements for perchloroethylene considerably exceed those for HCE, the regularities of the catalytic hydrodechlorination of HCE, pentachloroethane, 1,1,2,2-tetrachloroethane, 1,1,2-trichloroethane, and 1,2-dichloroethane are studied in part two, using 1.5 wt % Pd on sibunit as the catalyst. It is found the fraction of hydrogen substited for chlorine grows and the reactivity of the products diminishes with a reduction in the number of chlorine atoms in a polychloroethane molecule. Ethane and ethylene are the final reaction products after a rather long contact time. The kinetics of HCE catalytic hydrodechlorination is studied n the temperature range of 353-393 K and at hydrogen partial pressures of 50-810 kPa. It is shown that the only reaction product is perchloroethylene; i.e., the transformation of HCE proceeds via the elimination of two chlorine atoms, while the limiting stage of the process is product dissolution in the aqueous-alkaline reaction mass. The form of the kinetic equation is found to be w = 2.1 × 10 × exp[−(16200 ± 400)/ RT] C C $P_{H_2 }^{0.5} $ mol/(L s). The possibility of using the catalytic hydrodechlorination of chlorohydrocarbons in a medium of sodium hydroxide solutions for the recycling of chloroorganic wastes containing CCl and polychloroethanes is demonstrated. [ABSTRACT FROM AUTHOR]

Abstract: A non-agglomerated submicron-sized titanium carbide powder has been synthesised in a simple combustion process with titanium tetrachloride and hexachloroethane as reactants, and with magnesium as a reducing agent. X-ray analysis of the purified product revealed that only the cubic titanium carbide phase is present. High-resolution transmission electron microscopy showed that TiC particles are coated with low-ordered carbon film on the surface. To remove free carbon, a melting process with calcium metal was used. [Copyright &y& Elsevier]

Carbon tetrachloride, classified as an ozone-depleting substance in the Montreal Protocol, is formed as a byproduct in the production of chlorinated hydrocarbons (chloromethanes, perchloroethylene, etc.). To develop a rational method of CCl utilization (an alternative to burning), in this work we study the liquid-phase catalytic hydrodechlorination of CCl with the formation of useful products such as sodium formiate, hexachloroethane, and perchloroethylene in the presence of aqueous sodium hydroxide solutions. Experiments are performed in a 300-mL autoclave at pressures of up to 1.5 MPa within a temperature range of 80-120°C on a Pd catalyst on sibunite (5 fractions, 0.1 to 1.6 mm). The dependences of the CCl conversion and the selectivities with respect to the principal reaction products on the initial concentrations of CCl and NaOH, the temperature, the partial pressure of hydrogen, the size of catalyst particles, and the palladium content in a catalyst are studied. Using the obtained data as a basis, we propose a process flowsheet, make some recommendations on the process conditions (depending on the specified composition of products), and determine the optimum catalyst characteristics: 1.5 wt % Pd on sibunite with a grain size of 0.315-0.63 mm. The proposed process allows us not only to solve the problem of recycling CCl-containing wastes, but also to provide the production of three marketable products. [ABSTRACT FROM AUTHOR]

The iminophosphorane 3, prepared by reaction of ethyl 4-amino-5-cyano-1-phenyl-1H-pyrrole-3-carboxylate (2) with triphenylphosphine, hexachloroethane and triethylamine, reacted with equimolar quantities of aromatic isocyanates to give carbodiimides 4. Further reaction of carbodiimides 4 with various amines or phenols then gave 2,3,6,7-tetrasubstituted 4,6-dihydro-4-oxo-3H-pyrrolo[3,4-d]pyrimidin-7-carbonitrile derivatives 6 in satisfactory yields in the presence of a catalytic amount of sodium ethoxide or potassium carbonate. [ABSTRACT FROM AUTHOR]

Abstract: The impact of co-solutes on sorption of tetrachloroethene (PCE) by two porous media with low organic-carbon contents was examined by conducting batch experiments. The two media (Borden and Eustis) have similar physical properties, but significantly different organic-carbon (OC) contents. Sorption of PCE was nonlinear for both media, and well-described by the Freundlich equation. For the Borden aquifer material (OC=0.03%), the isotherms measured with a suite of co-solutes present (1,2-dichlorobenzene, bromoform, carbon tetrachloride, and hexachloroethane) were identical to the isotherms measured for PCE alone. These results indicate that there was no measurable impact of the co-solutes on PCE sorption for this system. In contrast to the Borden results, there was a measurable reduction in sorption of PCE by the Eustis soil (OC=0.38%) in the presence of the co-solutes. The organic-carbon fractions of both media contain hard-carbon components, which have been associated with the manifestation of nonideal sorption phenomena. The disparity in results observed for the two media may relate to relative differences in the magnitude and geochemical nature of these hard-carbon components. [Copyright &y& Elsevier]

BACKGROUND: Tetrachloroethylene (PCE) and hexachloroethane (HCA) degradation, individually and in mixture, is investigated by Fe(III) or Fe(III)-citrate initiated Fenton reaction under a range of hydrogen peroxide (H2O2) concentrations to illustrate the applicability and constraints of Fenton chemistry in degrading contaminants in polluted groundwater. RESULTS: In individual solutions Fe(III) rapidly degraded PCE for all H2O2 concentrations, but HCA at ≥ 0.2 mol L−1 H2O2; the apparent PCE degradation rate initially increased but then decreased with increasing H2O2, while the HCA degradation rate was either unaffected or increased. With Fe(III)-citrate PCE degradation was lower and no HCA degradation occurred. PCE degradation was lower in PCE-HCA mixture, but the trend with H2O2 concentration was similar to the individual chemical; for HCA the residual was smaller for higher H2O2 concentration, but the apparent degradation rate constant was unaffected. CONCLUSION: Fe(III) catalyzed reactions can potentially degrade chemicals through reductive as well as oxidative transformations. Degradation of chemicals in mixtures occurs at a slower rate due to competition for radical moieties. The Fe(III)-citrate complex further slowed chemical transformation. This study expands on the use of different forms of iron to catalyze the Fenton reaction to degrade chemicals. Copyright © 2012 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

This study examined the influence of hexachloroethane coated mould on the mechanical properties of hypoeutectic aluminium-silicon alloy. A hypoeutectic aluminium-silicon alloy was grain refined using 15 wt-% hexachloroethane and cast at varied degrees of melt superheats (50-150°C). The mechanical properties of the cast ingots were measured and their microstructures studied. The grain sizes of the ingots cast at various superheats were also determined. The study revealed that the grain sizes decrease as the melt superheat decreases, thereby causing an increase in the mechanical properties of the alloy. It was also noted that there exists an optimum value of superheat at which the mechanical properties were optimum. Apart from improved mechanical properties, it was inferred that the application of volatile mould coating (hexachloroethane) and temperature control facilitates the production of porosity free hypoeutectic aluminium-silicon casting. [ABSTRACT FROM AUTHOR]

Abstract: Ionic liquids (ILs) have attracted the curiosity of researchers due to their unique properties in different applications such as separation, extraction, purification, catalysis and electrochemical applications. The generation of superoxide ion (O2 −) in ILs is one of these interesting areas. In this work O2 − was generated and analyzed electrochemically using cyclic voltammetry and chronoamperometry techniques from O2 dissolved in 1-butyl-1-methylpyrrolidinium trifluoroacetate, [BMPyrr][TFA]. Moreover, O2 − was generated chemically by the addition of potassium superoxide (KO2) into the same IL. UV/Vis spectrophotometer was used for testing the stability of the generated O2 − and GC/MS was used to investigate any possible reaction between [BMPyrr][TFA] and O2 −. For our best knowledge this is the first time that trifluoroacetate based IL was used for the generation of O2 −. The results showed that O2 − was very stable in this IL. This encourages further investigation on the use of this particular class of ILs in diverse applications involving the O2 −. The chemically generated O2 − by dissolving KO2 was then used for the destruction of hexachloroethane in [BMPyrr][TFA] under ambient conditions. The destruction percentage was higher than 98%. This work presents the first attempt to utilize KO2 for destruction of chloroethanes in ILs. [Copyright &y& Elsevier]

Copper-catalyzed functionalization of aliphatic tertiary amines with the assistance of C2Cl6 is described. This method details the alkynylation of aliphatic tertiary amines and the synthesis of methylene-bridged bis-1,3-dicarbonyl derivatives. The mechanism of the selective oxidation of aliphatic tertiary amines was also discussed. A broad spectrum of aliphatic tertiary amines was examined in this methodology. [ABSTRACT FROM AUTHOR]

The generation of reactive species in activated persulfate systems under different conditions of basicity was investigated using three probe compounds. Anisole was used to detect both sulfate radical and hydroxyl radical. Nitrobenzene was used to detect hydroxyl radical, and hexachloroethane was used as a reductant probe. Minimal probe compound degradation occurred in persulfate reactions conducted at pH≤10, demonstrating that a low flux of reactants is generated at acidic, neutral, and slightly basic pH regimes. In persulfate reactions at pH 12, sulfate and hydroxyl radical were generated but minimal reductants were produced. Scavenging studies showed that the dominant reactive species at basic pH was hydroxyl radical. The generation of reductants increased at high molar ratios of base to persulfate; however, hydroxyl radical generation rates increased only when molar ratios of base to persulfate were >3∶1. The results of this research demonstrate that the hydroxyl radical is the dominant reactive oxygen species in base-activated persulfate formulations and that overall reactivity increases with increasing base:persulfate ratios. [ABSTRACT FROM AUTHOR]