Decomposition Of Chloride Research Articles

Decomposition of Cyanogen Chloride by Using a Packed Bed Plasma Reactor at Dry and Wet Air in Atmospheric Pressure

The decomposition rate of CNCl in a BaTiO3-filled Packed Bed Plasma Reactor was studied as a function of AC input power, power frequency, residence time in the reactor, and inlet flow rate. The decomposition rate was compared with those of CH3CN and CCl2CHCl. Under the condition of 6.7 Wh/m3 specific energy den- sity, the decomposition rate of CNCl was found to be 50%, which is lower than those of CH3CN and CCl2CHCl at the same or similar conditions. At a higher frequency of the power input system, the decomposition rate of inlet gas becomes lower due to a decrease in field strength for the same level of power. And, under the same level of input power, a higher decomposition rate was obtained at an increased residence time. The relation between gas decomposition rates stemmed from the electron–molecule collision and bounding energy within the molecule. The decomposition ratio of CNCl was lower than those of CCl2CHCl and CH3CN because the bond strength of the weakest bond in the molecule is higher. In order to test the decomposition efficiency of CNCl with catalytic packing material in a plasma reactor, the catalyst of γ-Al2O3 and Pt/γ-Al2O3 was packed in the packed bed plasma reactor. Although byproducts were formed, the plasma-catalyst hybrid reactor containing Pt/γ-Al2O3 showed a higher efficiency in CNCl decomposition as shown in the decomposition rate of above 99% in 0.3 kWh/m3.

Nanostructure Pt Electrode Obtained via Self‐assembly of Nanoparticles on Conductive Oxide‐coated Glass Substrate

AbstractSelf‐assembly of platinum nanoparticles were applied to fabrication of counter electrode for dye‐sensitized solar cells on conductive oxide‐coated glass substrate. The present Pt electrode exhibits high exchange current density of 220 mA/cm2, which is comparable to those prepared by electrodeposition. magnetron sputtering or thermal decomposition of platinum chloride. After analysis by transmission electron microscopy (TEM). atomic force microscopy (AFM) and X‐ray photoelectron spectroscopy (XPS), it was found that the catalyst was structurally characterized as nanosized platinum metal clusters and was continuously arranged on electrode surface. The present nanostructure electrode had high electrocatalytic activity for the reduction of iodine in organic solution.

Decomposition of Mercuric Chloride and Application to Combustion Flue Gases

Environmental Context. The toxicity of the volatile metal mercury is well known; this Hg0 form accounts for about 99% of atmospheric mercury and the remainder the water-soluble oxidized (Hg+, Hg2+) form. The release of mercury from the atmosphere is measurable by a drop in the Hg0 levels, but to establish realistic scientific and regulatory standpoints the rate in which Hg0 converts to the oxidized forms needs to be understood. Conversely, from an industrial standpoint, understanding the rate at which the oxidized forms convert to Hg0 allows for better waste-scrubbing processes. Abstract. Theoretical rate constants and activation energies are predicted for the decomposition of mercuric chloride through the use of relativistic pseudopotentials for mercury at the B3LYP level of theory. The method and basis set combinations are validated through a comparison of theoretically determined geometries, frequencies, and reaction enthalpies to experimental values found in the literature. In addition, the theoretically predicted rate constants are compared to rate constants that have been predicted through combustion modelling of this reaction.

Thermal Decomposition Characteristics of Critical Components in Solid Wastes

The thermal and chemical behavior of the various compounds present in solid wastes is significantly different during all phases of thermal destruction. To develop advanced design for waste thermal destruction it is imperative that one must examine the thermal destruction behavior of different components in the wastes under controlled conditions. Results are presented on the thermal decomposition characteristics during the decomposition of polyethylene, polypropylene, polystyrene, polyvinyl chloride, and cellulose under controlled thermal and chemical environment. These compounds represent important composition of the wastes. Thermogravimetry (TGA) tests and Differential Scanning Calorimetry (DSC) tests have been conducted on the thermal decomposition of above materials (polyethylene, polypropylene, polystyrene, polyvinyl chloride, and cellulose) in inert (nitrogen) atmospheres. The tests were performed at a sample heating rate of 5, 10, 30, and 50°C/min. The DSC curves showed the heat flow into and out of the sample during the process of pyrolysis. The material composition and properties, heating rate, and surrounding gas chemical environment affect the material decomposition rates under defined conditions. The composition of waste materials significantly affects the thermal decomposition behavior. Experimental results show that decomposition process shifts to higher temperatures at higher heating rates as a result of the competing effects of heat and mass transfer to the material. The results on the maximum decomposition temperature and heat of pyrolysis obtained from the thermal decomposition of surrogate wastes showed significant different features between these materials. Energy evolved at the early stages from certain easy to decompose materials can be used to destruct the other materials that decompose at higher temperatures or require more energy to decompose. The energy required to decompose the material is only a small fraction of the chemical energy evolved from material. The results presented here assist in the design and development of advanced thermal destruction systems.

A thermal decomposition study on cobalt(II) complexes of 1,2-bis(IMINO-4'-antipyrinyl)ethane

Abstract The phenomenological, kinetic and mechanistic aspects of thermal decomposition of perchlorate, nitrate, chloride, bromide and iodide complexes of cobalt(II) with the Schiff base 1,2-bis(imino-4'-antipyrinyl)ethane (GA) have been studied by TG and DTG analyses. The kinetic parameters like the activation energy, pre-exponential factor and entropy of activation were calculated. The decomposition reactions follow 'random nucleation with one nucleus on each particle - Mampel model'.

The A to G of Chemical Equilibrium: Aspects Depicted by Helmholtz Energy Using Its Relationship to Gibbs Energy

The approach to chemical equilibrium at constant V, T is considered for various heterogeneous reactions and processes. Analysis is made showing how A and G conveniently interrelate enabling typical 2-D and 3-D Helmholtz energy curves to be drawn across a range of T to illustrate water vaporization and the thermal decomposition of calcium carbonate and ammonium chloride solids. A dip in free energy forms when gas component(s) change in pressure and amount as each reaction proceeds. Equilibrium is consequently attained by the opposing influence of these changes bringing the free energy to a minimum or the entropy to a corresponding maximum. Significantly this effect does not depend on a contribution from a free energy (or entropy) of mixing. The Helmholtz energy curves for the decomposition of ammonium chloride into ammonia and hydrogen chloride are obtained by using (equilibrium) vapor pressures for this two-gas formation and the effect of adding more of one of these gases is allowed for and depicted in co...

Catalytic decomposition of methylene chloride on oxidative carbon supported metal oxide catalysts II. Chromium oxide catalyst

Several carbon supported chromium oxide catalysts were prepared by varying textural and surface properties of support and tested for methylene chloride oxidation. They were investigated by TGA and XPS. The difference in acidity and high valence of chromium led to difference in activity.

A thermal decomposition study on cobalt(II) complexes of 1,2-di(imino-4′-antipyrinyl)ethane

The phenomenological, kinetic and mechanistic aspects of thermal decomposition of perchlorate, nitrate, chloride, bromide and iodide complexes of cobalt(II) with the Schiff base 1,2-di(imino-4′-antipyrinyl)ethane (GA) have been studied by TG and DTG analyses. The kinetic parameters like the activation energy, pre-exponential factor and entropy of activation were calculated. The decomposition reactions follow “random nucleation with one nucleus on each particle—Mampel model”.

Catalytic decomposition of methylene chloride by sulfated titania catalysts

Catalytic decomposition of methylene chloride in air below 300°C was studied. Sulfated titania was very effective in converting 959 ppm methylene chloride selectively to CO, CO2 and HCl. Complete decomposition of methylene chloride was achieved at low temperature (275°C). It was found that the acidic property of catalyst was a determinant factor for the catalytic activity. The presence of water vapor in the feed stream remarkably reduced the catalytic activity, which could be due to the blockage of acidic sites on the surface of catalyst by water molecules. A bifunctional catalyst comprising copper oxide was developed to improve the selectivity of catalytic oxidation, which indicated that copper oxide can promote the deep oxidation of methylene chloride. The crystal form of TiO2 imposes an important influence upon the catalytic oxidation.

The adsorption and decomposition of cyanogen chloride by modified inorganic molecular sieves

Aluminosilicate and silicate porous solids have been evaluated as supports for triethylenediamine (TEDA) for the adsorption and decomposition of cyanogen chloride. A series of silica-gel supports has been used to study the effect of varying pore size. A series of faujasitic zeolites has been used to examine the effect of the cation exchange capacity of the support and the type of exchangeable cation. Results show that the activity of adsorbed TEDA towards cyanogen chloride appears to increase with increasing support pore diameter, and TEDA seems to be activated by basic adsorption sites on the support. Cesium-exchanged zeolite supports are particularly active. In general, zeolite supports appear to confer significantly higher activity to TEDA than traditional activated carbon supports. A series of mesoporous MCM-41 and AlMCM-41 supports has also been studied, but the activities of adsorbed TEDA are lower than expected. Significantly, the specific surface area of the inorganic supports does not seem to be a primary factor in controlling adsorbed TEDA activity.

The Role of Nucleophiles in the Kinetics of Decomposition of Benzyltriphenyl-Phoshponium Chloride in Different Media

The alkaline decomposition of benzyltriphenylphosphonium chloride was studied kinetically in a series of DMSO-H

Metalorganic chemical vapor deposition of oxide films on semiconductor substrates using aluminum, gallium, and indium alkyl chloride precursors

The thermal decomposition of dipropylaluminum, dipropylgallium, and dipropylindium chlorides was investigated by thermal analysis. The growth kinetics of oxide films on silicon and gallium arsenide were studied, using dipropylaluminum, dipropylgallium, and dipropylindium chlorides; propylaluminum and propylgallium dichlorides; ethylaluminum dichloride; and diethylaluminum and diethylindium chlorides as metalorganic precursors. The resultant films were characterized by IR and x-ray spectroscopies and electrical measurements.

Thermally prepared Ti/RhOx electrodes: II H2 evolution in acid solution

Ti/RhOx electrodes were prepared at 400-600?C by thermal decomposition of Rh chloride. Oxide layers were studied by SEM, cyclic voltammetry and steady-state E-j curves In 0.5 mol dm-3 H2SO4 solution. Voltammetric charge exhibits a maximum at 430?C with fresh electrodes which shifts to 470?C after use for H2 evolution. H2 discharge first produces a decrease in voltammetric charge, then an activation with final settlement to a constant behaviour for "aged" electrodes. H2 evolution on stable RhOx surfaces takes place with 40 mV Tafel slope and a reaction order of 2.5. The fractional reaction order indicates that the surface response to pH is that typical of oxides even for "aged" electrodes. A reaction mechanism is proposed.

Thirty minutes laser calcination method for the preparation of DSA ® type oxide electrodes

In this paper, a new approach for the preparation of dimensionally stable anodes DSA ® type oxide electrodes, using a CO 2 laser as a heat source, is proposed. Commercial composition of (TiO 2) 0.7(RuO 2) 0.3 was used for this feasibility study in which thermal decomposition of precursor chlorides, for the growth of a coating 2–3 μm thick, is carried out in 30 min. The resulting oxide layer presented the usual cracked-mud morphology that lasted 8 h in an accelerated service life test at 400 mA cm −2 , in a H 2SO 4 1 M solution. The results involving the effects of laser beam power and scan rate are examined. Voltammetric anodic charge was maximized by the combination of 15 W beampower, focal distance of 210 mm and beam scan rate of 35 mm s −1 . By cycling potential between 0.2 and 1.1 V vs SCE the oxide coating behaved as a capacitor capable of being charged and discharged reversibly and the cathodic/anodic charge ratio remained close to one. Currents related to oxygen evolution reaction were observed after 1.37 V vs SCE.

Oxidative decomposition of chlorinated hydrocarbons by glow discharge in PACT (plasma and catalyst integrated technologies) reactors

The oxidative decomposition of methyl chloride (CH 3Cl) and methylene chloride (CH 2Cl 2) by glow discharge has been carried out in a new type of reactor using plasma and catalyst integrated technologies (PACT) in our laboratory. The PACT reactors with metal (Fe, Pt, or Au) coated electrodes were used in our experiments at room temperature and atmospheric pressure. Feed compositions were 5000 ppm of either CH 3Cl or CH 2Cl 2 and 5% of oxygen with a balance of helium and a total flow rate of around 20 ml/min. Significant conversions (as high as 90%) of CH 3Cl or CH 2Cl 2 have been achieved for the oxidative decomposition of CH 3Cl or CH 2Cl 2 using PACT reactors.

Hydrolytic removal of the chlorinated products from the oxidative free-radical-induced degradation of chloroethylenes: acid chlorides and chlorinated acetic acids

Progressive hydrolytic decomposition of acyl chlorides, among them the chlorinated acetyl chlorides, which are produced in the gas-phase oxidation of chlorinated ethylenes, permits the complete mineralization of organically bound chlorine to chloride anion. Hydrolysis rate constants (100% water) have been determined for the following acyl chlorides: acetyl (350 s−1), chloroacetyl (5.5 s−1), dichloroacetyl (300 s−1), trichloroacetyl (>350 s−1), and oxalyl dichloride (>350 s−1). The chlorinated acetyl chlorides thereby give rise to the chloroacetates whose decomposition has also been studied and the kinetic parameters determined. Mono- and dichloroacetate anion undergo hydrolytic dechlorination (kobs = ko + kOH− × [OH−]; ClCH2C(O)O−: Ao 6.4 × 1015 s−1, Eo 148 kJ mol−1, AOH− 1.6 × 109 dm3 mol−1 s−1, EOH− 86 kJ mol−1. Cl2CHC(O)O−: Ao 3.2 × 1016 s−1, Eo 156 kJ mol−1, AOH− 3.2 × 1010 dm3 mol−1 s−1, EOH− 104 kJ mol−1). Trichloroacetate anion decomposes by another mechanism, undergoing decarboxylation which is base-uncatalyzed: Ao 2.1 × 1017 s−1, Eo 146 kJ mol−1. Procedures on a pilot-plant scale are pointed out that allow the elimination of these compounds upon oxidation of the strip-gas produced when contaminated water is freed from chlorinated ethylenes by air-stripping.

Study on the electro-activity and non-stochiometry of a Ru-based mixed oxide electrode

Catalytic oxide electrodes of Ru/Ti, RuSn/Ti, and RuSnTi/Ti effective in destroying refractory organics in aqueous waste were studied in terms of material and electrochemical properties. The portion of non-stochiometry, RuO x (0< x<2) and chloride-bonded Ru within the Ru-based oxide were evaluated by deconvolution of XPS of the oxide with a change of sintering temperature. RuO x mostly existed around 450°C, and disappeared at 600°C. The component of chloride-bonded Ru decreased nearly linearly from 350 to 600°C. The non-stochiometry resulted from the incomplete decomposition of metal chloride in the precursor solution. The existence of non-stochiometry was confirmed to have a close relation to the electrochemical activity of the oxide electrode. The segregation phenomena of Sn and the existence of chloride in RuSnTi/Ti oxide after sintering were confirmed by AES, XPS, and EPMA.

A theoretical study on decomposition of carbon tetrachloride, trichloroethylene and ethyl chloride in dry air under the influence of an electron beam

New experimental data were published in literature regarding CCl 4 , C 2 HCl 3 and C 2 H 5 Cl decomposition in dry air under electron beam influence. Taking into account experimental data theoretical models of those species decomposition were established and computer simulations were performed by the authors of this work to find the kinetics of such processes. The results of the calculations and experimental data show that CCl 4 decomposition depends on delivered dose and initial CCl 4 concentrations. The calculation revealed that recombination of CCl + 4 and Cl − is the source of CCl 3 radicals and that reaction may have an important role in the process of CCl 4 decomposition. A theoretical model of C 2 HCl 3 decomposition in dry air under electron beam influence describes the decay of C 2 HCl 3 and the formation of several products such as Cl 2 , CCl 2 O, CO, CO 2 , HCl and C 2 HCl 3 O. The detailed comparison of experimental and theoretical data shows relatively good agreement in efficiency of C 2 HCl 3 decomposition process, but it can be achieved only with an assumption that the relation between rate constants of C 2 HCl 4 O intermediate product decomposition (C 2 HCl 3 O+Cl and COCl 2 +CHCl 2 ) should be around 20 and C 2 HCl 3 O oxidation rate should be not lower than 7.5×10 −11 cm 3 /mols. All those rate constants are not yet established experimentally. The results of the calculation of C 2 H 5 Cl decomposition and the data obtained experimentally were compared. The temperature, gas pressure, initial C 2 H 5 Cl concentration and dose range were equal in both cases. An elaborated model allow us to obtain quantitatively similar results as the experiments, but the degree of C 2 H 5 Cl decomposition for certain dose levels is significantly higher in experimental data. It is quite probable that some important processes have not been included to the theoretical model.

Hypochlorite-induced oxidation of thiols: Formation of thiyl radicals and the role of sulfenyl chlorides as intermediates

Activated phagocytic cells generate hypochlorite (HOCl) via release of hydrogen peroxide and the enzyme myeloperoxidase. HOCl plays an important role in bacterial cell killing, but excessive or misplaced production of HOCl is also known to cause tissue damage. Studies have shown that low-molecular-weight thiols such as reduced glutathione (GSH), and sulfur-containing amino acids in proteins, are major targets for HOCl. Radicals have not generally been implicated as intermediates in thiol oxidation by HOCl, though there is considerable literature evidence for the involvement of radicals in the metal ion-, thermal- or UV light-catalysed decomposition of sulfenyl or sulfonyl chlorides which are postulated intermediates in thiol oxidation. In this study we show that thiyl radicals are generated on reaction of a number of low-molecular-weight thiols with HOCl. With sub-stoichiometric amounts of HOCl, relative to the thiol, thiyl radicals are the major species detected by EPR spin trapping. When the HOCl is present in excess over the thiol, additional radicals are detected with compounds which contain amine functions; these additional radicals are assigned to nitrogen-centered species. Evidence is presented for the involvement of sulfenyl chlorides (RSCl) in the formation of these radicals, and studies with an authentic sulfenyl chloride have demonstrated that this compound readily decomposes in thermal-, metal-ion- or light-catalysed reactions to give thiyl radicals. The formation of thiyl radicals on oxidation of thiols with HOCl appears to compete with non-radical reactions. The circumstances under which radical formation may be important are discussed.

Studies on (non) energetic compounds. Part-14: Thermal decomposition of dimethylanilinium chlorides

Six dimethylanilinium chlorides (DMACl) have been prepared and characterised. Thermal decomposition of these salts have been studied by TG and DSC techniques. Kinetic parameters have been evaluated from the isothermal and non-isothermal TG data, Contracting area, Contracting cube and Coats–Redfern equations have been found to give the best fits. The decomposition pathways have also been suggested. It has been observed that simultaneous sublimation/decomposition processes are involved during the thermal decomposition of DMACl.