Kinetics of the thermal decomposition of cyclobutanone

1969 ◽  
Vol 47 (4) ◽  
pp. 615-617 ◽  
Author(s):  
Arthur T. Blades
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Carbon Monoxide ◽  
Rate Constant ◽  
Relative Rate ◽  
Relative Rate Constant ◽  
Pressure Sensitive ◽  
Photochemical Decomposition ◽  
Kinetics Of ◽  
Constant Expression

The thermal decomposition of cyclobutanone into cyclopropane and carbon monoxide has been shown to occur simultaneously with the major decomposition to ethylene and ketene. The relative rate constant expression is given by [Formula: see text] Both reactions are pressure sensitive below 10 Torr and this quasi-unimolecular behavior is most pronounced in the cyclopropane forming reaction, consistent with the higher activation energy. The data are also discussed in relation to the photochemical decomposition and it is shown that cyclopropane formation from the ground singlet is an important feature of the photolysis at 3130 Å.

THE THERMAL DECOMPOSITION OF PHENYLACETIC ACID

1960 ◽  
Vol 38 (8) ◽  
pp. 1261-1270 ◽  
Author(s):  
Margaret H. Back ◽  
A. H. Sehon
Keyword(s):  
Carbon Dioxide ◽  
Activation Energy ◽  
Thermal Decomposition ◽  
Carbon Monoxide ◽  
Rate Constant ◽  
Phenylacetic Acid ◽  
Order Process ◽  
First Order ◽  
Kinetics Of ◽  
Dissociation Step

The thermal decomposition of phenylacetic acid was investigated by the toluene-carrier technique over the temperature range 587 to 722 °C. The products of the pyrolysis were carbon dioxide, carbon monoxide, hydrogen, methane, dibenzyl, and phenylketene. From the kinetics of the decomposition it was concluded that the reaction[Formula: see text]was a homogeneous, first-order process and that the rate constant of this dissociation step was represented by the expression k = 8 × 1012.e−55,000/RT sec−1. The activation energy of this reaction may be identified with D(C6H5CH2—COOH). The possible reactions of carboxyl radicals are discussed.

THE SECONDARY HYDROGEN ISOTOPE EFFECTS IN THE PYROLYSIS OF ETHYL-d5 ACETATE AND ETHYL ACETATE-d3

1960 ◽  
Vol 38 (9) ◽  
pp. 1407-1411 ◽  
Author(s):  
Arthur T. Blades ◽  
P. W. Gilderson
Keyword(s):  
Ethyl Acetate ◽  
Rate Constant ◽  
Hydrogen Isotope ◽  
Experimental Error ◽  
Relative Rate ◽  
Isotope Effects ◽  
Relative Rate Constant ◽  
Temperature Ranges ◽  
Relative Rate Constants ◽  
Constant Expression

Rate constant expressions have been obtained for ethyl acetate and ethyl-d5 acetate in the temperature ranges 500–603 °C and 501–614 °C.[Formula: see text]By measuring the relative rate of production of C2H4 and C2D4 from identical mixtures of the two esters at the temperatures 387 and 490 °C, it has been possible to determine the temperature coefficient of the relative rate constant more accurately. This, coupled with the relative rate constants at 500 °C derived from the above equations, gives the relative rate constant expression.[Formula: see text]These data are compared with the intramolecular isotope effect in the decomposition of ethyl-1,1,2,2-d4 acetate, and the differences attributed to secondary isotope effects.The rate of decomposition of ethyl acetate-d3 was found to be identical within experimental error with that of the normal acetate.

scholarly journals The combination of carbon monoxide–haem with apoperoxidase

1969 ◽  
Vol 114 (4) ◽  
pp. 719-724 ◽  
Author(s):  
Charles Phelps ◽  
Eraldo Antonini
Keyword(s):  
Activation Energy ◽  
Carbon Monoxide ◽  
Rate Constant ◽  
Binding Sites ◽  
Order Process ◽  
First Order ◽  
Effects Of Ph ◽  
Kinetics Of

1. Static titrations reveal an exact stoicheiometry between various haem derivatives and apoperoxidase prepared from one isoenzyme of the horseradish enzyme. 2. Carbon monoxide–protohaem reacts rapidly with apoperoxidase and the kinetics can be accounted for by a mechanism already applied to the reaction of carbon monoxide–haem derivatives with apomyoglobin and apohaemoglobin. 3. According to this mechanism a complex is formed first whose combination and dissociation velocity constants are 5×108m−1sec.−1 and 103sec.−1 at pH9·1 and 20°. The complex is converted into carbon monoxide–haemoprotein in a first-order process with a rate constant of 235sec.−1 for peroxidase and 364sec.−1 for myoglobin at pH9·1 and 20°. 4. The effects of pH and temperature were examined. The activation energy for the process of complex-isomerization is about 13kcal./mole. 5. The similarity in the kinetics of the reactions of carbon monoxide–haem with apoperoxidase and with apomyoglobin suggests structural similarities at the haem-binding sites of the two proteins.

Kinetic Study of the Pyrolysis of Formaldehyde

1972 ◽  
Vol 50 (7) ◽  
pp. 992-998 ◽  
Author(s):  
C. J. Chen ◽  
D. J. McKenney
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Carbon Monoxide ◽  
Kinetic Study ◽  
Pressure Range ◽  
Heterogeneous Reaction ◽  
Experimental Results ◽  
Arrhenius Parameters ◽  
Rate Laws ◽  
Kinetics Of

Kinetics of the thermal decomposition of pure formaldehyde were studied over a temperature range of 466–516 °C and a pressure range of ~ 50–160 Torr. Arrhenius parameters and rate laws were determined for carbon monoxide, hydrogen and methanol as follows:[Formula: see text]A mechanism is postulated which is qualitatively consistent with the experimental results but the activation energy for reaction 1[Formula: see text]is ~15 kcal/mol lower than predicted from recent thermochemical data, suggesting the possibility of a heterogeneous reaction.

scholarly journals The thermal decomposition of nitrogen iodide

1940 ◽  
Vol 174 (958) ◽  
pp. 410-424 ◽  
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Experimental Research ◽  
Mechanical Shock ◽  
Air Temperatures ◽  
Alternative Formula ◽  
Photochemical Decomposition ◽  
Falling Weight ◽  
The Impact ◽  
Kinetics Of

Bunsen (1852) was the first to suggest that the formula of nitrogen iodide was NH 3 . NI 3 , although this was disputed later on account of the fact that any attempts made to remove the ammonia resulted in complete decomposition. An alternative formula, NH 2 I.NHI 2 , which took account of this fact, was, however, disproved by Silberrad (1905), who prepared triethylamine by the action of zinc ethyl on nitrogen iodide. Eggert (1921) investigated the thermal decomposition of nitrogen iodide and showed that the following equation represented the changes occurring during detonation, thermal or photochemical decomposition: (1) 8NH 3 .NI 3 → 5N 2 + 6NH 4 I + 9I 2 . The primary step (also suggested by Chattaway and Orton (1900) for the photochemical decomposition) was supposed to be: (2) NH 3 .NI 3 = N 2 + 3HI, followed by either or both of the following reactions: (3) 5HI + NH 3 .NI 3 → 2NH 4 I + 3I 2 ; (4) 3HI + 7NH 3 .NI 3 = 4N 2 + 6NH 4 I + 9I 2 . These results were obtained when the products were allowed to accumulate up to atmospheric pressures. The present investigation has shown that the decomposition takes a different course if the products are removed in high vacua. The properties of the substance when subjected to mechanical shock are well known. Under the impact of a small falling weight it detonates even at liquid-air temperatures (Eggert 1921). Eggert states that the detonation of this substance occurs under the action of pressure alone (at 5000 atm.) even when the substance is wet. Garner and Latchem (1936) showed that the substance detonates in a hard vacuum immediately it is dry, an observation which was confirmed by Belajev and Chariton (1936). The decomposition proceeds quietly at - 10° C if the pressure of the gas above the crystals be not allowed to fall below 2 x 10 -3 cm., the reaction slowing up as the products accumulate and coming to a standstill before all of the iodide is decomposed. It was suggested by Garner and Latchem that one of the products acted as a retarding agent stabilizing the solid. It was thought that the retarding agent was iodine, but this has been shown by the present investigation to be incorrect. In spite of the large volume of experimental research on nitrogen iodide, the details of the kinetics of its decomposition are still very obscure. Neither the activation energy nor the heat liberated in its decomposition is known, and there has been no extended investigation into its sensitivity to heat or to shock. It has been the object of this investigation to obtain information along these lines and also to throw some light on the initiation of detonation generally.

THE HYDROGEN ISOTOPE EFFECTS IN THE PYROLYSIS OF ETHYL-1,1,2,2-d4 BROMIDE AND OF ETHYL-d5 BROMIDE

1962 ◽  
Vol 40 (8) ◽  
pp. 1533-1539 ◽  
Author(s):  
Arthur T. Blades ◽  
P. W. Gilderson ◽  
M. G. H. Wallbridge
Keyword(s):  
Isotope Effect ◽  
Rate Constant ◽  
Hydrogen Isotope ◽  
Relative Rate ◽  
Isotope Effects ◽  
Side Reaction ◽  
Relative Rate Constant ◽  
Temperature Range ◽  
Rate Controlling Step ◽  
Constant Expression

The relative rate constant expression has been obtained for the decomposition of ethyl-1,1,2,2-d4 bromide under inhibiting conditions in the temperature range 697.6 to 999.1 °K,[Formula: see text]The pressure dependence of the isotope effect has been investigated both with and without inhibitor, and in each case it has been shown that the isotope effect increases with decreasing pressure.The relative rate constant expression for the ethyl-h5, ethyl-d5 bromide comparison was also obtained in the temperature range 730.9 to 964.8 °K,[Formula: see text]The isotope effect is again pressure dependent, falling to lower values as the pressure is decreased.The data are used to demonstrate that the inhibited decomposition of ethyl bromide is primarily a molecular process, and that the rate-controlling step involves a carbon–hydrogen bond break.A side reaction that produces small amounts of ethane has been observed.

Thermal Decomposition Kinetics of RDX with Distributed Activation Energy Model

2013 ◽  
Vol 641-642 ◽  
pp. 144-147 ◽  
Author(s):  
Ming Hua Chen ◽  
Tao Zhang ◽  
Wen Ping Chang ◽  
Xiao Biao Jia
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Energy Model ◽  
Decomposition Kinetics ◽  
Thermal Decomposition Kinetics ◽  
Distributed Activation Energy Model ◽  
Thermogravimetric Analyzer ◽  
Decomposition Stage ◽  
Decomposition Processes ◽  
Kinetics Of

The thermal decomposition kinetics of RDX at different rates was studied by thermogravimetric analyzer(TG) and the activation energy of RDX was calculated by distributed activation energy model. It is shown that the thermal decomposition processes of RDX were divided into three stages according to the TG curves, they are molten stage, thermal decomposition stage and eng stage. The activation energies of RDX are all between 124.34 and 181.48KJ•mol-1 in the thermal decomposition stage of non-monotonously increasing. The activation energy of RDX is 139.98 KJ•mol-1 in the molten stage, and the thermal decomposition stage is167.24KJ•mol-1.

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).

THE KINETICS OF CUPRENE GROWTH

1950 ◽  
Vol 28b (7) ◽  
pp. 358-372
Author(s):  
Cyrias Ouellet ◽  
Adrien E. Léger
Keyword(s):  
Nitric Oxide ◽  
Activation Energy ◽  
Carbon Monoxide ◽  
Apparent Activation Energy ◽  
Copper Catalyst ◽  
Maximum Velocity ◽  
Static System ◽  
Reaction Velocity ◽  
First Order ◽  
Kinetics Of

The kinetics of the polymerization of acetylene to cuprene on a copper catalyst between 200° and 300 °C. have been studied manometrically in a static system. The maximum velocity of the autocatalytic reaction shows a first-order dependence upon acetylene pressure. The reaction is retarded in the presence of small amounts of oxygen but accelerated by preoxidation of the catalyst. The apparent activation energy, of about 10 kcal. per mole for cuprene growth between 210° and 280 °C., changes to about 40 kcal. per mole above 280 °C. at which temperature a second reaction seems to set in. Hydrogen, carbon monoxide, or nitric oxide has no effect on the reaction velocity. Series of five successive seedings have been obtained with cuprene originally grown on cuprite, and show an effect of aging of the cuprene.

scholarly journals Analysis of the Kinetics of Swimming Pool Water Reaction in Analytical Device Reproducing Its Circulation on a Small Scale

Sensors ◽  
2020 ◽  
Vol 20 (17) ◽  
pp. 4820 ◽  
Author(s):  
Wojciech Kaczmarek ◽  
Jarosław Panasiuk ◽  
Szymon Borys ◽  
Aneta Pobudkowska ◽  
Mikołaj Majsterek
Keyword(s):  
Activation Energy ◽  
Water Quality ◽  
Rate Constant ◽  
Reaction Rate ◽  
Reaction Rate Constant ◽  
Small Scale ◽  
Pool Water ◽  
Swimming Pool Water ◽  
Kinetics Of ◽  
Analytical Device

The most common cause of diseases in swimming pools is the lack of sanitary control of water quality; water may contain microbiological and chemical contaminants. Among the people most at risk of infection are children, pregnant women, and immunocompromised people. The origin of the problem is a need to develop a system that can predict the formation of chlorine water disinfection by-products, such as trihalomethanes (THMs). THMs are volatile organic compounds from the group of alkyl halides, carcinogenic, mutagenic, teratogenic, and bioaccumulating. Long-term exposure, even to low concentrations of THM in water and air, may result in damage to the liver, kidneys, thyroid gland, or nervous system. This article focuses on analysis of the kinetics of swimming pool water reaction in analytical device reproducing its circulation on a small scale. The designed and constructed analytical device is based on the SIMATIC S7-1200 PLC driver of SIEMENS Company. The HMI KPT panel of SIEMENS Company enables monitoring the process and control individual elements of device. Value of the reaction rate constant of free chlorine decomposition gives us qualitative information about water quality, it is also strictly connected to the kinetics of the reaction. Based on the experiment results, the value of reaction rate constant was determined as a linear change of the natural logarithm of free chlorine concentration over time. The experimental value of activation energy based on the directional coefficient is equal to 76.0 [kJ×mol−1]. These results indicate that changing water temperature does not cause any changes in the reaction rate, while it still affects the value of the reaction rate constant. Using the analytical device, it is possible to constantly monitor the values of reaction rate constant and activation energy, which can be used to develop a new way to assess pool water quality.

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