Decomposition Of Chloride Research Articles

Phase transition and thermal decomposition of [Al(DMSO)6]Cl3

Phase transition and thermal decomposition of hexadimethylsulfoxidealuminium chloride were studied by differential scanning calorimetry (DSC), thermogravimetry (TG) and simultaneous differential thermal analysis (SDTA). The gaseous products of the decomposition were on-line identified by a quadrupole mass spectrometer (QMS). In the temperature range of 95–300 K, [Al(DMSO)6]Cl3 indicates one phase transition at Tch=244.96 K (on heating) and at Tcc=220.87 K (on cooling). Large thermal hysteresis of the phase transition (∼24 K) indicates its first order character. Large value of transition entropy (ΔS≈40 J mol−1 K−1) suggests its configurational character. Thermal decomposition of the title compound proceeds in four main stages. In the first stage, which starts just above ca. 300 K, the compound loses two DMSO molecules per one formula unit and undergoes into [Al(DMSO)4]Cl3. In the second stage, the next three DMSO ligands are released and simultaneously decomposed. The third stage, which continues up to ca. 552 K, is connected with a loss of the last DMSO ligand and the formation of AlCl3. In the fourth stage AlCl3 reacts with carbon monoxide that originates from the decomposition of DMSO, and first aluminium oxychloride and next solid Al2O3 plus carbon are created.

Decomposition of propionyl chloride triggered by slow electrons

Low energy electron attachment to propionyl chloride is studied by means of a crossed beam experiment. Two distinct resonances are observed located near 0 and 0.7 eV. The first resonance is attributed to a temporary occupation of the lowest unoccupied molecular orbital (LUMO) with predominant π C O ∗ character. It mainly decays into Cl −, but also the fragments (M–CH 2) −, COCl − and (M–Cl) − are observed. In addition the non-decomposed parent molecular anion M − is observed. The second resonance exclusively leads to Cl − formation. It is characterized as temporary occupation of a repulsive σ C – Cl ∗ MO.

Laser Transmission Welding of Thermoplastics—Part II: Experimental Model Validation

Two laser transmission welding experiments involving polyvinyl chloride are presented that aim to validate a previously presented welding model while helping to further understand the relationship between welding parameters and weld quality. While numerous previous research papers have presented the results of laser welding experiments, there exists minimal work validating models of the welding process. The first experiment explores the interaction of laser power and welding velocity while the second experiment explores the influence of clamping pressure. Using the weld width as the primary model output, the agreement between the welding experiments and the model have an average error of 5.6%. This finding strongly supports the validity of the model presented in Part I of this two paper set (Van de Ven and Erdman, 2007, ASME J. Manuf. Sci. Eng., 129, pp. 849–858). Additional information was gained regarding the operating window for laser transmission welding and the thermal decomposition of polyvinyl chloride. Clamping pressure was found to provide a small, but not statistically significant, influence on the visual appearance, weld width, and weld strength.

Size control synthesis of polymer-stabilized water-soluble platinum oxide nanoparticles

A series of narrowly distributed nanoparticles with different sizes of platinum oxide stabilized by polyvinylpyrrolidone (PVP) were synthesized by hydrolytic decomposition of platinum chloride. The as-synthesized nanoparticles were characterized by UV–vis, TEM, and XPS examination. Studies on the parameters influencing the size of the as-synthesized platinum oxide nanoparticles were carried out. The pH of the solution was demonstrated to be the main factor affecting the particle diameter. The particles size also decreased with the increasing molar ratio of stabilizer (PVP):PtCl 4. The influence of the concentration of sodium acetate on the rate of hydrolytic decomposition and the condensation reaction was studied. It was found that increasing the concentration of sodium acetate increased the rate of the condensation reaction nearly linearly.

Water Solvent Method for Esterification and Amide Formation between Acid Chlorides and Alcohols Promoted by Combined Catalytic Amines: Synergy between N‐Methylimidazole and N,N,N′,N′‐Tetramethylethylenediamine (TMEDA)

AbstractAn efficient method for esterification between acid chlorides and alcohols in water as solvent has been developed by combining the catalytic amines, N‐methylimidazole and N,N,N′,N′‐tetramethylethylenediamine (TMEDA). The present Schotten–Baumann‐type reaction was performed by maintaining the pH at around 11.5 using a pH controller to prevent the decomposition of acid chlorides and/or esters and to facilitate the condensation. The choice of catalysts (0.1 equiv.) was crucial: the combined use of N‐methylimidazole and TMEDA exhibited a dramatic synergistic effect. The catalytic amines have two different roles: (i) N‐methylimidazole forms highly reactive ammonium intermediates with acid chlorides and (ii) TMEDA acts as an effective HCl binder. The production of these intermediates was rationally supported by a careful 1H NMR monitoring study. Related amide formation was also achieved between acid chlorides and primary or secondary amines, including less nucleophilic or water‐soluble amines such as 2‐(or 4‐)chloroaniline, the Weinreb N‐methoxyamine, and 2,2‐dimethoxyethanamine.

Electrocatalysis of H2 evolution by thermally prepared ruthenium oxide

Abstract Ruthenium oxide (formally RuO2) was deposited on Ti by thermal decomposition of Ru chloride as well as Ru nitrate. Electrodes were prepared in a range of temperatures, 260–550 °C, and characterized by SEM and cyclic voltammetry. The voltammetric charge q∗, obtained by integration of the CV curves, was recorded as a function of calcination temperature. q∗ is higher for nitrate than for chloride. H2 evolution was used as a probe reaction to test the electrocatalytic properties. Polarization curves were recorded and analyzed to obtain Tafel slopes. Results showed that the oxide from nitrate is more electrocatalytic than that from chloride. This is in part due to the more extended surface area of the former, but electronic factors related to the particle size are also evident. q∗ was recorded after each run of experiments and compared with the values before to monitor the stability of the oxide layer.

A Non-Alkoxide Sol−Gel Method for the Preparation of Homogeneous Nanocrystalline Powders of La0.85Sr0.15MnO3

Homogeneous, nanocrystalline La1-xSrxMnO3 (LSM) powders, with x ∼ 0.15, were synthesized with the epoxide addition sol−gel method. Through this simple technique, sol−gel materials were prepared from methanolic solutions of metal chlorides without the need for alkoxides, polymeric gel agents, or elaborate reaction schemes. The gels were dried in ambient conditions, resulting in mesoporous xerogels with networked nanostructures interconnecting particulate regions. Calcination of the dried gels resulted in the crystallization of single-phase LSM by 700 °C, after decomposition of intermediate hydroxide, chloride, and oxychloride compounds. SEM analysis indicated that the calcined powders were nanocrystalline and consisted of discrete particles, free of hard agglomeration. The average crystallite size and equivalent spherical diameter determined from XRD line broadening and BET analysis, respectively, were in good agreement with the SEM results (∼100 nm). The activation energies for the electronic conductivity...

Thermolytic investigations on nickel(II) complexes of 4-N-(4′-antipyrylmethylidene)aminoantipyrine with various counterions

Phenomenological characteristics and kinetic and mechanistic aspects of the thermal decomposition of nitrate, chloride, bromide, and iodide complexes of nickel(II) with 4-N-(4′-antipyrylmethylidene)aminoantipyrine have been studied using thermogravimetric (TG) and differential thermogravimetric (DTG) techniques. Kinetic parameters such as activation energy, preexponential factor, and entropy of activation were quantified. The rate-controlling process in all stages of decomposition was found to be based on random nucleation with one nucleus on each particle according to the Mampel model. © 2006 Wiley Periodicals, Inc. Int J Chem Kinet 39: 53–58, 2007

Dynamical Steric Effect in the Decomposition of Methyl Chloride on a Silicon Surface

We report results of a study on the incident energy and the surface-temperature dependence of the steric effects in the dissociative adsorption of CH3Cl on a Si{100} surface. Data presented here show that the initial sticking probability for the Cl-end collision is larger at an incident energy of 120 meV than that in the CH3-end collision. Furthermore, this steric preference is quite sensitive to the kinetic energy and the rotational state of CH3Cl and the surface temperature. This study shows that the nonequilibrium surface trapping plays a key role in the initial step of the decomposition of CH3Cl on Si{100}.

Effects of heating rate, temperature and iron catalysis on the thermal behaviour and decompostion of 2-nitrobenzoyl chloride

Runaway reactions arising from the decomposition of thermally unstable materials are a concern in industry due to the potentially devastating effects that they yield. Studies into the occurrence of thermal runaway incidents have shown the most likely cause to be a result of an inadequate investigation of the process prior to its operation on a large-scale. The chlorination of ortho-nitrated carboxylic acids is an industrially important reaction in the fine and agrochemical industries. The products of these reactions, ortho-nitrated acid chlorides, have been involved in runaway incidents that have resulted in violent explosions; hence, their thermal stability must be studied. Previous studies [S.D. Lever, M. Papadaki, Study of condition-dependent decomposition reactions: the thermal behaviour and decompostion of 2-nitrobenzoyl chloride, Part I, J. Hazard. Mater. 115 (2004) 91–100] showed that the decomposition of the parent molecule, 2-nitrobenzoyl chloride, is highly condition-dependent with the sample heating rate and temperature of decomposition playing a preponderant role in the course of the decomposition. Here, we present the results of studies of the decomposition of 2-nitrobenzoyl chloride, when the sample is subjected to various heating treatments, temperatures and in the presence of iron. As the temperature of decomposition was increased from 150 to 162 °C, the heat of decomposition was reduced from −215 to −90 kJ/mol. As the heat up rate applied in bringing the sample to the decomposition temperature increased, the heat of decomposition also increased. An increase in the heat up rate from 2 to 7.5 °C/min resulted in an increase in the heat of decomposition from −90 to −215 kJ/mol. The presence of iron and silver was observed to lower the heat of decomposition from −185 to −160 and −110 kJ/mol, respectively. Under most conditions investigated, the temperature at which gas flow was initiated was 147–150 °C. The presence of iron reduced this temperature to 140 °C. Decomposition was observed to take place over two stages, where the sample was heated directly from 40 °C at the required heat up rate. Where the sample was heated in stages and where calibrations had been carried out preceding decomposition, the decomposition took place in one stage alone.

A Theoretical Study of the Mechanism of the Water-Catalyzed HCl Elimination Reactions of CHXCl(OH) (X = H, Cl) and HClCO in the Gas Phase and in Aqueous Solution

A systematic ab initio investigation of the water-assisted decomposition of chloromethanol, dichloromethanol, and formyl chloride as a function of the number of water molecules (up to six) building up the solvation shell is presented. The decomposition reactions of the chlorinated methanols and formyl chloride are accelerated substantially as the reaction system involves additional explicit coordination of water molecules. Rate constants for the decomposition of chlorinated methanols and formyl chloride were found to be in reasonable agreement with previous experimental observations of aqueous phase decomposition reactions of dichloromethanol [CHCl(2)(OH)] and formyl chloride. For example, using the calculated activation free energies in conjunction with the stabilization free energies from the ab initio calculations, the rate constant was predicted to be 1.2-1.5 x 10(4) s(-1) for the decomposition of formyl chloride in aqueous solution. This is in good agreement with the experimental rate constant of about 10(4) s(-1) reported in the literature. The mechanism for the water catalysis of the decomposition reactions as well as probable implications for the decomposition of these chlorinated methanol compounds and formaldehydes in the natural environment and as intermediates in advanced oxidation processes are briefly discussed.

On the use of Diefallah's composite integral method for the non-isothermal kinetic analysis of heterogeneous solid-gas reactions

The paper contains an analysis of the used of Diefallah's composite integral method of kinetic parameters evaluation. It is shown that the application of this method should be preceded by the application of an isoconversional method through which the dependence of the activation energy, E, on the conversion degree, a, should be established. If Edepends on a, Diefallah's composite integral method leads to erroneous results. If Edoes not depend on a, the true kinetic model should be comprised in the pre-established set of kinetic models. These observations were checked for two sets of non-isothermal data, namely: (a) the TG curves corresponding to the dehydration of CaC2O4·H2O; (b) the TG curves corresponding to the thermal decomposition of polyvinyl chloride (PVC).

Solubility and calorimetric study of the effects of gas environment on the decomposition of o-nitrobenzoyl chloride

When ortho -nitrated benzoic acids are chlorinated in xylene and acetonitrile, the product gases, HCl and SO 2 , dissolve in the solvent mixture. Previously measured solubilities [Lever, S. D., Papadaki, M. (2004a). o -Chlorination of 2-nitrobenzoic acid with thionly chloride in xylene and acetonitrile. Solubility study of hydrogen chloride and sulphur dioxide in xylene and acetonitrile, IChemE transactions part B. Process Safety and Environmental Protection . 48–60.] were compared to other published data and found to be in very good agreement. The heat of solution of SO 2 in xylene was evaluated calorimetrically and compared to the value obtained from our previous experimental work. In our previous work [Lever, S. D., Papadaki, M. (2004b). Study of condition-dependent decomposition reactions—the thermal behaviour and decomposItion of 2-nitrobenzoyl chloride part_I. Journal of Hazardous Materials . 115; pp. 91–100], it was reported that the products of the decomposition are condition dependent. The current study showed that the decomposition is extensively promoted by the presence of HCl. This has important safety implications should the process operating temperature be reduced and HCl solution in the solvent mixture be increased. If a thermal runaway began in the increased availability of HCl, an undesirable escalation of the runaway could occur.

Thermo-oxidative decomposition of polyvinyl chloride

Pyrolysis and combustion of polyvinyl chloride resin have been studied by thermogravimetric analysis. Nine different runs with about 5 mg sample mass have been carried out in three different atmospheres (He; He:O 2 9:1; and He:O 2 4:1) and heating rates (5, 10 and 20 °C/min). Adequate kinetic simplified models have been proposed and all heating rates have been simultaneously correlated with the same set of kinetic constants, obtaining good results. The pyrolysis model consists of one first reaction producing gases and solid residue followed by two parallel reactions of previous solid, whereas the combustion model adds a third parallel reaction with oxygen and three new combustion reactions to burn char formed in the three previous reactions. Different considerations have been taken into account during the optimization to achieve the best results. Parameters obtained have been discussed and also compared with others from literature.

The Kinetic Studies of Elimination of HCl During Thermal Decomposition of PVC in the Presence of Transition Metal Oxides

: The effects of nine kinds of transition metal oxides on the elimination kinetics of hydrogen chloride (HCl) during thermal decomposition of polyvinyl chloride (PVC) at 210°C were investigated using online measurement of conductivity. It was found that the presence of TiO2, V2O5, Cr2O3, and MoO3 obviously decreases the elimination rate of HCl and the amount of HCl released by a factor of 10–20 times, indicating that they have a strong inhibiting effect on the release of HCl. The presence of MnO2, ZnO, CuO, Co2O3, and Fe2O3 promotes the elimination of HCl during thermal decomposition of PVC. The maximum elimination rate of HCl in PVC/ZnO, especially, is ca. 10 times as high as that of PVC. In this work, the LnLn kinetic model, Ln(1 − α) = − ktn, describes the kinetics of elimination of HCl during thermal decomposition of PVC. The elimination rate of HCl during thermal decomposition of PVC increases with the rise of the apparent order of reaction, n, in this model n value well describes the elimination kinetics of HCl during thermal decomposition of PVC.

Water-solvent method for tosylation and mesylation of primary alcohols promoted by KOH and catalytic amines

We have developed an efficient water-solvent method for p-toluenesulfonylation (tosylation) and methanesulfonylation (mesylation) of primary alcohols using p-toluenesulfonyl chloride and methanesulfonyl chloride, respectively, promoted by KOH and catalytic amines. The reaction was performed by maintaining the pH at around 10 using a pH controller to prevent the undesirable decomposition of sulfonyl chlorides. Several primary alcohols were smoothly sulfonylated in excellent yield. The choice of the amine catalyst (0.1 equiv.) was important: N,N-dimethylbenzylamine, a sterically unhindered and lipophilic tertiary amine, was effective for the tosylation, whereas N,N-dimethylbutylamine and triethylamine were effective for the mesylation. The present Schotten–Baumann-type method is the first example of catalytic sulfonylation using sulfonyl chlorides, and is a green chemical process due to the use of water as the solvent.

Determination of Chemical Kinetic Parameters of Surrogate Solid Wastes

Results on the thermal decomposition behavior of several important components in solid wastes are presented under controlled chemical and thermal environments. Thermogravimetry (TGA) tests were conducted on the decomposition of cellulose, polyethylene, polypropylene, polystyrene and polyvinyl chloride in inert (nitrogen), and oxidative (air) atmospheres. Inert condition tests were performed at heating rates of 5, 10, 30, and 50°C/min while the oxidative condition tests were performed at one heating rate of 5°C/min. Differential scanning calorimetry (DSC) was also used to measure the heat flow into and out of the sample during thermal decomposition of the material. The TGA results on the mass evolution of the materials studied as a function of temperature showed that the cellulose contained a small amount of moisture whereas no moisture was found in the other materials examined. The DSC curve showed the heat flow into and out of the sample during the process of pyrolysis and oxidative pyrolysis. The temperature dependence and mass loss characteristics of materials were used to evaluate the Arrhenius kinetic parameters. The surrounding chemical environment, heating rate, and material composition and properties affect the overall decomposition rates under defined conditions. The composition of these materials was found to have a significant effect on 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 Arrhenius chemical kinetic parameters and heat of pyrolysis obtained from the thermal decomposition of the sample materials showed that different components in the waste have considerably different features. The thermal decomposition temperature, heat evolved and the kinetics parameters are significantly different various waste components examined. The amount of thermal energy required to destruct a waste material is only a small faction of the energy evolved from the material. These results assist in the design and development of advanced thermal destruction systems.

M. Carey Lea, the first mechanochemist

The experiments of M. Carey Lea (1823-1897) are usually considered the first systematic investigations on the chemical effects of mechanical action. This paper collects the most important facts about Lea's life and discusses his research from the point of view of mechanochemistry. Lea was born into a family of considerable privilege and exceptional achievements. He suffered from weak health throughout his life. Consequently, he was educated at home by a tutor and later worked in the private laboratory of his home in Philadelphia. Lea was primarily a photochemist, his first mechanochemical observation in 1866 concerned the pressure sensitivity of photographic plates. Later in his life, he investigated the effect of various kinds of energy—heat, light, mechanical action—on allotropic (colloidal) silver and silver halides. The “parallelism” of the results motivated Lea to study the mechanochemical decomposition of dozens of stable compounds between 1892 and 1894. He observed the decomposition of silver and mercuric chlorides by trituration in a mortar, although the same compounds are known to melt or sublime undecomposed when heated. Lea was elected member of the National Academy of Sciences in 1892.

Study of condition-dependent decomposition reactions: Part I. The thermal behaviour and decompostion of 2-nitrobenzoyl chloride

The risks associated with batch processing in the manufacture of chemicals and pharmaceuticals via highly exothermic reactions are of special interest due to the possibility of runaway reactions. o-Nitrated benzoyl chlorides are intermediates in the production of agrochemicals and are produced via the reaction of o-nitrated carboxylic acids with thionyl chloride in a solvent mixture. ortho-Nitrated acyl chlorides have exploded violently on attempted distillation on numerous occasions. An inadequate investigation of the process prior to large-scale operation is the most likely cause. Here we present preliminary results of studies on the decomposition of 2-nitrobenzoyl chloride. This study has revealed that the decomposition reaction is strongly condition dependent. The heating rate of the sample plays a preponderant role in the course of the decomposition reaction. That renders the interpretation of differential scanning calorimetry (DSC) or adiabatic calorimetry measurements, which are routinely used to assess the thermochemistry and safety of the large-scale reactions, problematic. Following this on-going study, we report here key features of the system that have been identified.

Spectroscopic ellipsometry characterization of ZnO–In 2O 3 systems

The pseudobinary oxides of zinc-indium-oxide systems (ZnO–In 2O 3) with high conductivity and transparency were the subject of this work. The films were prepared on heated glass substrates by spray pyrolytic decomposition of zinc chloride with indium chloride in distilled water. The spectroscopic ellipsometry and atomic force microscopy (AFM) were used to analyze the optical properties and the surface structures of ZnO–In 2O 3 films deposited. The ellipsometric parameters tan ψ and cosΔ were measured using a rotating polarizer spectroscopic ellipsometer in the wavelength range (0.4–1.5 μm) at two incident angles of 65 and 70°. The layer roughness was modeled as an effective mixture of 50% ZnO–In 2O 3 and 50% voids in good agreement with the direct AFM measurement. The complex refractive index and electrical resistivity for several [Zn]/ [Zn+In] ratios (at.%) were determined and analyzed.