Showing papers on "Thermal decomposition published in 1976"
514 citations
294 citations
TL;DR: In this article, simple thermal decomposition reactions have been investigated for the purpose of solar thermal energy storage and the efficiency of storage is high and the decomposition occurs in the vicinity of 500°C.
214 citations
124 citations
TL;DR: In this paper, the thermal decomposition of low-density polyethylene, isotactic polypropylene, and polyisobutylene has been studied in helium at a heating rate of 20°C/min using an experimental system which consists of a programmable pyrolyzer, a thermal conductivity cell, and a mass chromatograph.
Abstract: The thermal decomposition of low-density polyethylene, isotactic polypropylene, and polyisobutylene has been studied in helium at a heating rate of 20°C/min using an experimental system which consists of a programmable pyrolyzer, a thermal conductivity cell, and a mass chromatograph.
For low-density polyethylene, the formation of a homologous series of volatile products corresponding to alkanes and alkanes is interpreted in terms of an intramolecular radical transfer process in the primary macroradicals to the 5th, 9th, 13th, and 17th carbon atoms of the chain.
For isotactic polypropylene, the formation of a homologous series of volatile products corresponding to monomer, dimers, trimers, and higher oligomers is explained also in terms of intramolecular radical transfer processes. Transfers to the 5th, 9th, and 13th carbon atoms in the secondary macroradicals (indexing from the secondary carbon atom at the chain end) and transfers to the 6th, 10th, and 12th carbon atoms in the primary macroradicals are shown to account for the major products of pyrolysis.
For polyisobutylene, in addition to the depolymerization process which accounts for the extensive formation of monomer, intramolecular radical transfer processes in the primary and tertiary macroradicals (the processes proceeding predominantly in the primary macroradicals) are shown to account for the formation of the dimers, trimers, and higher oligomers that occur in the volatile products of decomposition.
113 citations
TL;DR: In this article, the authors investigated the kinetics of the thermal decomposition of CaCO 3 in CO 2 using both dynamic and isothermal techniques and concluded that thermal transport rather than mass transport or chemical processes is rate determining.
103 citations
TL;DR: In this article, mass spectroscopically, the hydrogen and oxygen evolution from MgO prepared by thermal decomposition of high purity Mg(OH)2 was studied.
99 citations
TL;DR: In this paper, it has been shown that the kinetic compensation effect observed in thermal decomposition reactions is not due to the special form of the Arrhenius equation, and the validity of a linear kinetic compensation law implies the existence of a characteristic temperature at which the rate constants of all reactions have the same value, but this temperature can be higher or lower than the temperatures at which a decomposition takes place.
Abstract: On the basis of theoretical TG curves it has been shown that the kinetic compensation effect observed in thermal decomposition reactions is not due to the special form of the Arrhenius equation. Formally, the validity of a linear kinetic compensation law implies the existence of a characteristic temperature at which the rate constants of all reactions have the same value, but this temperature can be higher or lower than the temperatures at which the decomposition takes place.
97 citations
TL;DR: In this article, the lattice constants of most compounds were obtained from powder data or single-crystal data and were compared with earlier measurements as far as such as such were available, and the hydrates formed by the various compounds were studied by thermal decomposition under constant H2O partial pressure.
Abstract: The compounds MIUO2XO4· yH2O and MII(UO2XO4)2· zH2O(X = P, As; MI = H, Li, Na, K, NH4; MII = Mg, Ca, Sr, Ba; y = 0…4; z = 0…11) have been prepared and systematically studied. The hydrogen compounds HUO2PO4 · 4H2O and HUO2AsO4 · 4H2O were grown as single crystals by diffusing solutions of UO2(NO3)2, H3PO4 and H3AsO4, respectively, into large volumes of water. The alkali and alkaline-earth compounds were prepared by exchange of the H+ ions in the hydrogen compounds for alkalior alkaline-earth ions in MICl or MIICl2 solutions, respectively. The hydrates formed by the various compounds were studied by thermal decomposition under constant H2O partial pressure. The lattice constants of most compounds were obtained from powder data or—in some cases—single-crystal data and were compared with earlier measurements as far as such were available.
75 citations
TL;DR: In this paper, the size and shape of silicon particles were investigated by electron microscopy and they were found to be single crystalline and mostly defect free with three kinds of crystal habits: octahedral, tetrahedral and truncated triangular bipyramidal.
67 citations
TL;DR: In this paper, the authors studied the flash decomposition of CH3COOH on a clean nickel surface following adsorption at 30°C in order to access the applicability of chemical reaction rate theory to a homologous series of reactants on a well-defined surface.
TL;DR: The decomposition of 2-chloroethylphosphonic acid in aqueous solution has been studied at pH values from 6 to 9 and at temperatures in the 30 to 55 C range and the rate is proportional to the concentration of the phosphonate dianion and independent of the hydroxyl ion concentration.
Abstract: The decomposition of 2-chloroethylphosphonic acid in aqueous solution has been studied at pH values from 6 to 9 and at temperatures in the 30 to 55 C range. The rate of decomposition is estimated from the rate of formation of ethylene. The rate is proportional to the concentration of the phosphonate dianion and is independent of the hydroxyl ion concentration. The rate constant at 40 C is 1.9 x 10(-4) sec(-1) and the activation energy is 29.8 kcal mol(-1). The rate of reaction is not affected significantly by the presence of potassium iodide or urea (substances which increase the rate of leaf abscission in trees sprayed by 2-chloroethylphosphonic acid). The rate decreases slightly in the presence of low concentrations of magnesium and calcium ions.
TL;DR: In the thermal decomposition of methane at temperatures from 880 to 1103 K, hydrogen and ethane are the only primary products as mentioned in this paper, and the rate of formation of ethane falls rapidly towards zero as the reac...
Abstract: In the thermal decomposition of methane at temperatures from 880 to 1103 K, hydrogen and ethane are the only primary products. The rate of formation of ethane falls rapidly towards zero as the reac...
TL;DR: In this paper, the thermal decomposition products of copper dimethyldithiocarbamate and copper diethyldithium carbamate have been semi-quantitatively analyzed by a combined gas chromatography-based technique.
Abstract: The thermal decomposition products of copper dimethyldithiocarbamate and copper diethyldithiocarbamate have been semi-quantitatively analyzed by a combined gas chromatography — mass spectrometry technique and thermal decomposition mechanisms for both complexes are proposed. The fragmentation pathway is strongly influenced by the nature of the terminal alkyl group attached to the dithiocarbamate moiety.
Patent•
27 Aug 1976TL;DR: In this article, peroxyacid compounds are stabilized against excessive heat generation as the result of exothermic decomposition by the addition of a nonhydrated material which chemically decomposes to start releasing water at a temperature below the acid's decomposition temperature.
Abstract: Organic peroxyacid compounds are stabilized against excessive heat generation as the result of exothermic decomposition by the addition of a nonhydrated material which chemically decomposes to start releasing water at a temperature below the acid's decomposition temperature.
TL;DR: In this paper, a scheme of decomposition involving two paths, each with a two stage formation of methanes, was suggested, and strong evidence exists for slow hydrogen exchange between the eyelopentadienyl rings and the methyl groups before significant production of ethane.
TL;DR: The kinetic behavior of methanol adsorbed on alumina powder was studied by thermal desorption and isotopic tracer techniques using an ultrahigh vacuum system.
TL;DR: In this paper, the authors investigated the thermal decomposition of barium titanyl oxalate tetrahydrate (BTO) using TGA, DTG and DTA techniques and gas and chemical analysis.
TL;DR: In this article, the results were converted to weight loss by a correlation developed from subsidiary fixed-bed experiments and mass balances on the fluidized bed of sand in an atmosphere of nitrogen at temperatures up to 400 °C.
TL;DR: In this article, a detailed investigation of the mechanism of decomposition of dolomite in a specially designed thermal apparatus has been performed, and it has been shown that CO2 pressure affects both the initial decomposition temperature into MgO and CaCO3 and the final decomposition temperatures in opposite directions.
Patent•
28 May 1976TL;DR: In this article, a fluorinated elastomer is blended with a polyvinylidene fluoride resins at a temperature between the temperature of 70°C below the melting temperature of the resin and the decomposition temperature of same resin to form a resin blend capable of giving shaped articles having superior mechanical strength.
Abstract: A fluorinated elastomer is blended with a poly(vinylidene fluoride) resin at a temperature between the temperature of 70° C below the melting temperature of the resin and the decomposition temperature of the same resin to form a resin blend capable of giving shaped articles having superior mechanical strengths. The resin blend is suitable for preparing heat-shrinkable articles like heat-shrinkable tubes by heating with expansion by internal pressure at an elevated temperature higher than the melting temperature of the resin, followed by cooling without release of the pressure to room temperature where the pressure is released. Such heat-shrinkable tubes can readily become shrunken by re-heating.
TL;DR: In this article, the authors showed that at temperatures up to 390o, the carbon dioxide and alcohol decompose at similar rates with E (kJ mol-1) 182.6, 182.0, 181.0 and log A (s-1), 11.72, 13.06, 11.89 and 11.97, respectively.
Abstract: Dimethyl carbonate does not decompose at temperatures up to 390o. At 300-400o ethyl methyl, diethyl, ethyl propyl and dipropyl carbonates yield carbon dioxide, the alkene and the alcohol at similar rates with E (kJ mol-1) 182.0, 195.0, 181.6, 182.0 and log A (s-1) 11.72, 13.06, 11.89, 11.97, respectively. With ethyl propyl carbonate, ethylene is the slightly favoured alkene.
TL;DR: In this article, it was shown that the orthorhombic β-Rh2O3 is the most stable oxide under normal pressure, it decomposes irreversibly and probably topotactically to χ-Rh 2O3 at higher temperatures.
TL;DR: In this paper, the thermal decomposition of pentaerythritol tetranitrate (PETN) was studied below its m.p. 141 °C, and both sublimation and decomposition were found concurrently.
Abstract: The thermal decomposition of pentaerythritol tetranitrate (PETN) has been studied below its m.p. 141 °C. Both sublimation and decomposition are found to occur concurrently. Decomposition begins at ca. 75 °C and pressure–time curves show an initial rapid acceleration in decomposition. An activation energy of 192 ± 5 kJ mol–1 is obtained between 75 and 130 °C. It is suggested that decomposition takes pace in the vapour phase. Mass spectra of the decomposition products show that the distribution is temperature dependent.
TL;DR: In this article, a linear correlation between the activation energies and the number of methylene groups in the sequence between the maleimide residues was found for five aliphatic poly(bismaleimides) and showed that they follow first-order kinetic law up to a conversion of 60-70% having activation energies between 196 and 256 kj/mole.
Abstract: Thermal decomposition of poly(bismaleimides) has been investigated by using programmed and isothermal thermogravimetric analysis (TGA) in nitrogen. Reaction rates and overall activation energies were calculated from isothermal weight less studies. For five aliphatic poly(bismaleimides) a linear correlation between the activation energies and the number of methylene groups in the sequence between the maleimide residues was found. Aliphatic poly(bismaleimides) follow first-order kinetic law up to a conversion of 60-70% having activation energies between 196 and 256 kj/mole. poly(2,4-bismaleimidotoluene) which was found to have in highest polymer decomposition temperature (PDT) did follow the first-order kinetics up to a conversion of 60% in contrast to other aromatic poly(bismaleimides). In addition to the TGA, the pyro-field ion mass spectra of the polymers were recorded and are discussed.
TL;DR: In this paper, the volatile products resulting from the solid-state thermal decomposition of the dimethylmetallocenes Cp2M(CH3)2 (M = Ti, Zr, Hf) have been characterized by gas chromatography-mass spectrometry.
TL;DR: In this paper, the thermal decomposition of dihydrogen phosphates and arsenates was studied by thermal gravimetry and evolved gas analysis, and trends in the decomposition as a function of alkali metal and deuterium substitution were discussed.