The thermal oxidation of methylene chloride

1959 ◽  
Vol 250 (1261) ◽  
pp. 197-211 ◽  
Keyword(s):  
Thermal Decomposition ◽  
Chain Length ◽  
Methylene Chloride ◽  
Decomposition Reaction ◽  
Average Chain Length ◽  
Static System ◽  
Chain Process ◽  
Branched Chain ◽  
Considerable Detail ◽  
Kinetics Of

A study of the kinetics of the slow oxidation of methylene chloride has been made using a static system and the results of this are compared with those of flow-system experiments in which the composition of the reacting system was determined in considerable detail by gaschromatographic analysis. The reaction shows all the symptoms of a degenerately branched chain process and is similar to the corresponding thermal decomposition reaction in many respects. Several of the chlorinated hydrocarbon minor products are identical with those found in the thermal decomposition and this, together with kinetic evidence, suggests that the primary chain is the same in both reactions, oxygen intervening only in the conversion of the intermediate, dichlorethylene, to the end products HCl and carbon monoxide, and in the branching step, through which it modifies the overall rate. As in the thermal decomposition several of the organic minor products are susceptible to attack by chlorine atoms participating in the main chain and this prevents an accurate evaluation of the chain length by measurement of the rate of formation of termination products. The average chain length, however, appears to be of the order of ten. Methylene chloride + oxygen mixtures show a single explosion limit above about 600° C, which obeys the Semenov equation log 10 p = A / T + B , A being a constant for the system and B depending on the geometry of the vessel.

Thermal Decomposition Kinetics of Flame Retardant Polybutylene Terephthalate Matrix Composites

2019 ◽  
Vol 956 ◽  
pp. 181-191
Author(s):  
Jian Lin Xu ◽  
Bing Xue Ma ◽  
Cheng Hu Kang ◽  
Cheng Cheng Xu ◽  
Zhou Chen ◽  
...  
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Flame Retardant ◽  
Mass Loss Rate ◽  
Decomposition Reaction ◽  
Decomposition Kinetics ◽  
Thermal Decomposition Kinetics ◽  
Heating Rates ◽  
Polybutylene Terephthalate ◽  
Kinetics Of

The thermal decomposition kinetics of polybutylene terephthalate (PBT) and flame-retardant PBT (FR-PBT) were investigated by thermogravimetric analysis at various heating rates. The kinetic parameters were determined by using Kissinger, Flynn-Wall-Ozawa and Friedman methods. The y (α) and z (α) master plots were used to identify the thermal decomposition model. The results show that the rate of residual carbon of FR-PBT is higher than that of PBT and the maximum mass loss rate of FR-PBT is lower than that of PBT. The values of activation energy of PBT (208.71 kJ/mol) and FR-PBT (244.78 kJ/mol) calculated by Kissinger method were higher than those of PBT (PBT: 195.54 kJ/mol) and FR-PBT (FR-PBT: 196.00 kJ/mol) calculated by Flynn-Wall-Ozawa method and those of PBT and FR-PBT (PBT: 199.10 kJ/mol, FR-PBT: 206.03 kJ/mol) calculated by Friedman methods. There is a common thing that the values of activation energy of FR-PBT are higher than that of PBT in different methods. The thermal decomposition reaction models of the PBT and FR-PBT can be described by Avarami-Erofeyev model (A1).

Synthesis and Determination of the Kinetic Parameters for Non-Isothermal Decomposition of Complexes Ln(thd)3phen

2006 ◽  
Vol 530-531 ◽  
pp. 506-512 ◽  
Author(s):  
Wilton Silva Lopes ◽  
Crislene Rodrigues da Silva Morais ◽  
A.G. de Souza
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Lanthanide Complexes ◽  
Reaction Order ◽  
Decomposition Reaction ◽  
Cylindrical Symmetry ◽  
Boundary Reaction ◽  
Phase Boundary Reaction ◽  
Kinetics Of

In this work the kinetics of the thermal decomposition of two ß-diketone lanthanide complexes of the general formula Ln(thd)3phen (where Ln = Nd+3 or Tm+3, thd = 2,2,6,6- tetramethyl-3,5-heptanodione and phen = 1,10-phenantroline) has been studied. The powders were characterized by several techniques. Thermal decomposition of the complexes was studied by non-isothermal thermogravimetry techniques. The kinetic model that best describes the process of the thermal decomposition of the complexes it was determined through the method proposed by Coats-Redfern. The average values the activation energy obtained were 136 and 114 kJ.mol-1 for the complexes Nd(thd)3phen and Tm(thd)3phen, respectively. The kinetic models that best described the thermal decomposition reaction the both complexes were R2. The model R2 indicating that the mechanism is controlled by phase-boundary reaction (cylindrical symmetry) and is defined by the function g(α) = 2[1-(1-a)1/2], indicating a mean reaction order. The values of activation energy suggests the following decreasing order of stability: Nd(thd)3phen > Tm(thd)3phen.

scholarly journals Kinetics of White Soft Minerals (WSMs) Decomposition under Conditions of Interest for Astrobiology: A Theoretical and Experimental Study

Geosciences ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 101 ◽  
Author(s):  
Gaia Micca Longo ◽  
Marcella D’Elia ◽  
Sergio Fonti ◽  
Savino Longo ◽  
Francesca Mancarella ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Decomposition Reaction ◽  
Gas Diffusion ◽  
Spectroscopic Technique ◽  
Experimental Results ◽  
Additional Contribution ◽  
Atmospheric Entry ◽  
Entry Models ◽  
Kinetics Of

In this paper, the thermal decomposition kinetics of a class of minerals that we call White Soft Minerals (WSMs) is studied by means of theoretical and experimental methods, in connection to the transport of extraterrestrial organic matter to Earth and the possible use of the decomposition reaction in the characterization of these minerals in space. WSMs include, under a single denomination, carbonates and sulphates of Mg, Fe, and Ca. To improve the present knowledge of the properties of such materials, we use the following techniques: kinetic models for chemical decomposition, atmospheric entry models, spectroscopy, and gravimetric analyses. Model results show that the atmospheric entry of WSM grains is strongly affected by their thermal decomposition. The decomposition reaction, being strongly endothermic, tends to significantly lower the grain temperature during the atmospheric entry, especially at high altitudes and for grazing entries. A previously proposed infrared spectroscopic technique to evaluate the degree of advancement of the reaction is found to be in good agreement with gravimetric measurements for calcium carbonate. The numerical model developed for the atmospheric entry scenarios is used to interpret experimental results. These main findings show that an additional contribution to the reaction enthalpy is needed to reproduce the experimental results, suggesting that the present theoretical model needs improvements such as the account of gas diffusion in the materials.

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