KINETICS OF THE THERMAL DECOMPOSITION OF TETRAMETHYLTETRAZEN

1960 ◽  
Vol 38 (2) ◽  
pp. 298-299 ◽  
Author(s):  
J. S. Watson ◽  
A. J. Waring
Keyword(s):  
Thermal Decomposition ◽  
Static System ◽  
Arrhenius Parameters ◽  
First Order ◽  
Kinetics Of

The kinetics of the thermal decomposition of tetramethyltetrazen (T.M.T.) have been studied in a static system at pressures up to 1.8 × 10−2 mm and temperatures between 125.5 and 147.5 °C by measuring the rate of production of nitrogen. The results show that the decomposition is first order in T.M.T. at the pressures used and give approximate values for the Arrhenius parameters.

The gas-phase photochemistry and thermal decomposition of glyoxylic acid

1985 ◽  
Vol 63 (2) ◽  
pp. 542-548 ◽  
Author(s):  
R. A. Back ◽  
S. Yamamoto
Keyword(s):  
Thermal Decomposition ◽  
Carbon Monoxide ◽  
Absorption Spectrum ◽  
Gas Phase ◽  
Singlet State ◽  
Glyoxylic Acid ◽  
Static System ◽  
First Order ◽  
Increasing Temperature ◽  
Homogeneous Formation

The photolysis of glyoxylic acid vapour has been studied at five wavelengths, 382, 366, 346, 275, and 239 nm, and pressures from about 1 to 6 Torr, at a temperature of 355 K. Major products were CO2 and CH2O, initially formed in almost equal amounts, while minor products were CO and H2. Except at 382 nm, the system was complicated by the rapid secondary photolysis of CH2O. Three primary processes are suggested, each involving internal H-atom transfer followed by dissociation.The absorption spectrum is reported and shows the three distinct absorption systems. A finely-structured spectrum from about 320 to 400 nm is attributed to a transition to the first excited π* ← n+ singlet state; a more diffuse absorption ranging from about 290 nm to a maximum at 239 nm is assigned to the π* ← n− state, while a much stronger absorption beginning below 230 nm is attributed to the π* ← π transition. Product ratios vary with wavelength and depend on which excited state is involved.The thermal decomposition was studied briefly in a static system at temperatures from 470 to 710 K and pressures from 0.4 to 8 Torr. Major products were again CO2 and CH2O, but the latter was always less than stoichiometric. First-order rate constants for the apparently homogeneous formation of CO2 are described by Arrhenius parameters log A (s−1) = 7.80 and E = 30.8 kcal/mol. Carbon monoxide and H2 were minor products, and the CO/CO2 ratio increased with increasing temperature and showed some surface enhancement at lower temperatures. The SF6-sensitized thermal decomposition of glyoxylic acid, induced by a pulsed CO2 laser, was briefly studied, with temperatures estimated to be in the 1100–1600 K range, and the CO/CO2 ratio increased with increasing temperature, continuing the trend observed in the static system.

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.

The thermal decomposition of cyclobutane-1,2-dione

1985 ◽  
Vol 63 (11) ◽  
pp. 2945-2948 ◽  
Author(s):  
J.-R. Cao ◽  
R. A. Back
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Vapor Pressure ◽  
Gas Phase ◽  
Rate Constant ◽  
Surface Reaction ◽  
Order Rate Constant ◽  
Reaction Vessel ◽  
Arrhenius Parameters ◽  
First Order

The thermal decomposition of cyclobutane-1,2-dione has been studied in the gas phase at temperatures from 120 to 250 °C and pressures from 0.2 to 1.5 Torr. Products were C2H4 + 2CO, apparently formed in a simple unimolecular process. The first-order rate constant was strongly pressure dependent, and values of k∞ were obtained by extrapolation of plots of 1/k vs. 1/p to1/p = 0. Experiments in a packed reaction vessel showed that the reaction was enhanced by surface at the lower temperatures. Arrhenius parameters for k∞, corrected for surface reaction, were log A (s−1) = 15.07(±0.3) and E = 39.3(±2) kcal/mol. This activation energy seems too low for a biradical mechanism, and it is suggested that the decomposition is probably a concerted process. The vapor pressure of solid cyclobutane-1,2-dione was measured at temperatures from 22 to 62 °C and a heat of sublimation of 13.1 kcal/mol was estimated.

THE THERMAL DECOMPOSITION OF STYRENE–BUTADIENE POPCORN POLYMER

1950 ◽  
Vol 28b (1) ◽  
pp. 5-16
Author(s):  
C. A. Winkler ◽  
J. Halpern
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Linear Relation ◽  
Frequency Factor ◽  
Thermal Reaction ◽  
Cross Linking ◽  
First Order ◽  
Bond Scission ◽  
Styrene Butadiene ◽  
Kinetics Of

At temperatures of the order of 250 °C., popcorn polymer undergoes decomposition to soluble polymer. The reaction is catalyzed by peroxides present in the popcorn when the latter is formed. These peroxides may be removed by extracting the polymer with benzene. The kinetics of both the catalyzed and purely thermal solubilization reactions were investigated. The rates of both reactions are first order, the catalyzed degradation having a higher activation energy and a higher frequency factor. The rate of the thermal reaction decreases and its activation energy increases with increasing butadiene content of the polymer. A linear relation between the activation energy and the log of the frequency factor, for the decomposition of popcorn polymers of different butadiene contents, was observed. The results indicate that the rate of solubilization is determined by the activation energy of the bond scission process, and is independent of the degree of cross-linking of the polymer.

scholarly journals The dissociation energy of the C-N bond in benzylamine

1949 ◽  
Vol 198 (1053) ◽  
pp. 285-292 ◽  
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Dissociation Energy ◽  
Heat Of Formation ◽  
Molar Ratio ◽  
Kcal Mole ◽  
First Order ◽  
First Order Kinetics ◽  
Permanent Gases ◽  
Kinetics Of

The kinetics of the thermal decomposition of benzylamine were studied by a flow method using toluene as a carrier gas. The decomposition produced NH 3 and dibenzyl in a molar ratio of 1:1, and small quantities of permanent gases consisting mainly of H 2 . Over a temperature range of 150° (650 to 800° C) the process was found to be a homogeneous gas reaction, following first-order kinetics, the rate constant being expressed by k = 6 x 10 12 exp (59,000/ RT ) sec. -1 . It was concluded, therefore, that the mechanism of the decomposition could be represented by the following equations: C 6 H 5 . CH 2 . NH 2 → C 6 H 5 . CH 2 • + NH 2 •, C 6 H 5 . CH 3 + NH 2 •→ C 6 H 5 . CH 2 • + NH 3 , 2C 6 H 5 . CH 2 •→ dibenzyl, and the experimentally determined activation energy of 59 ± 4 kcal./mole is equal to the dissociation energy of the C-N bond in benzylamine. Using the available thermochemical data we calculated on this basis the heat of formation of the NH 2 radical as 35.5 kcal./mole, in a fair agreement with the result obtained by the study of the pyrolysis of hydrazine. A review of the reactions of the NH 2 radicals is given.

The Thermal Decomposition of Boron Trimethyl

1962 ◽  
Vol 15 (4) ◽  
pp. 744 ◽  
Author(s):  
AS Buchanan ◽  
F Creutzberg
Keyword(s):  
Thermal Decomposition ◽  
Activation Energies ◽  
Major Product ◽  
Main Reaction ◽  
Static System ◽  
Hydrogen Formation ◽  
First Order ◽  
Rate Expression

The thermal decomposition of boron trimethyl has been studied in a static system in the range 468-513 �C and was found to be first order with a rate expression������������� k1=1.2 x 1012e-[56 000/RT] sec-1. The activation energies for methane and hydrogen formation were found to be 76 and 75 kcal, respectively. The stoicheiometry for the main reaction was found to be ���������������� 2B(CH3)3 → 2CH4 + H2 + [B(CH2)2]2. Preliminary experiments on the photolysis of boron trimethyl indicated that methane was the major product.

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.

THE KINETICS OF THE THERMAL DECOMPOSITION OF ETHYL BROMIDE AND ETHYL BROMIDE-d5

1958 ◽  
Vol 36 (7) ◽  
pp. 1043-1048 ◽  
Author(s):  
Arthur T. Blades
Keyword(s):  
Thermal Decomposition ◽  
Rate Constants ◽  
Pressure Effect ◽  
Ethyl Bromide ◽  
Carrier Gas ◽  
First Order ◽  
Order Rate ◽  
Kinetics Of

The kinetics of the pyrolysis of ethyl bromide and ethyl bromide-d5 have been studied using the toluene carrier gas technique. Variation of the pressure in the range 0.6 to 4.4 cm. Hg reveals what is believed to be a legitimate pressure effect on the first-order rate constants. The Arrhenius rate expressions determined at 4 cm. Hg pressure are: k(ethyl bromide) = 8.5 ± 1.6 × 1012e−52,200±300/RTsec−1 (T = 523°–633 °C);k(ethyl bromide-d5) = 2.1 ± 0.4 × 1013e−54,840±300/RT sec−1 (T = 531°–635 °C).The differences in the two rate expressions are discussed.

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.

THE KINETICS OF THE THERMAL DECOMPOSITION OF DISULPHUR DECAFLUORIDE

1951 ◽  
Vol 29 (6) ◽  
pp. 508-525 ◽  
Author(s):  
W. R. Trost ◽  
R. L. McIntosh
Keyword(s):  
Nitric Oxide ◽  
Thermal Decomposition ◽  
Heterogeneous Reaction ◽  
Homogeneous Reaction ◽  
Chain Reaction ◽  
First Order ◽  
Reaction Proceeds ◽  
Total Process ◽  
A Chain ◽  
Kinetics Of

The thermal decomposition of the gas disulphur decafluoride has been studied in a metal reactor. Analytical evidence showed that the reaction proceeds according to the equation S2F10 = SF6 + SF4.The reaction was found to be largely homogeneous, as the heterogeneous reaction accounted for less than 5% of the total process. The homogeneous reaction was shown to be first order, and in the temperature range investigated the rate is given by ln k = 47.09 − 49,200/RT. A chain reaction is postulated to explain the observed rate of the reaction. The effect of nitric oxide and acetylene dichloride on the rate and products of the reaction was investigated.

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