The kinetics of the thermal decomposition of branched-chain paraffin hydrocarbons - II. The isomeric hexanes

1952 ◽  
Vol 214 (1118) ◽  
pp. 339-343 ◽  
Keyword(s):  
Nitric Oxide ◽  
Activation Energy ◽  
Thermal Decomposition ◽  
Order Transition ◽  
First Order ◽  
Single Transition ◽  
Branched Chain ◽  
Kinetics Of ◽  
Constant Activation Energy ◽  
Methyl Pentane

In the study of the thermal decomposition of paraffins the contrast of iso -butane with n -butane and of the branched pentanes with normal pentane has led to the investigation of the isomeric hexanes. The nitric oxide-inhibited reaction of neo -hexane possesses a constant, activation energy at different initial pressures and shows a single transition from second to first order with increasing pressure. The reactions of 2:3-dimethyl-butane, 2-methyl-pentane and 3-methyl-pentane show a double-order transition and a rise in activation energy at lower initial pressures, as previously found for the higher normal paraffins.

The kinetics of the thermal decomposition of branched-chain paraffin hydrocarbons - I. iso -Butane, iso -pentane and neo -pentane

1952 ◽  
Vol 214 (1118) ◽  
pp. 330-338 ◽  
Keyword(s):  
Nitric Oxide ◽  
Activation Energy ◽  
Single Mode ◽  
Marked Contrast ◽  
Radical Chain ◽  
Chain Reactions ◽  
Branched Hydrocarbons ◽  
Branched Chain ◽  
Kinetics Of ◽  
Constant Activation Energy

The branched hydrocarbons iso -butane, iso -pentane and neo -pentane decompose partly by radical chain reactions suppressible by nitric oxide, and partly by molecular reactions. The latter are of the usual unimolecular type with constant activation energy which is interesting in view of the marked contrast with the reactions of the corresponding normal paraffins. The alternative chemical modes of decomposition of iso -butane occur in propor­tions independent of the pressure from 5 to 400 mm. With neo -pentane a single mode pre­dominates at all pressures.

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 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.

scholarly journals Kinetics and Mechanism of Thermal Decomposition of 1-R-Substituted bis(1,1-Dinitromethyl-3-Nitro- 1,2,4-Triazole-5-yl)

2020 ◽  
pp. 25-30
Author(s):  
Lyudmila А. Kruglyakova ◽  
Rudolf S. Stepanov ◽  
Konstantin V. Pekhotin ◽  
Oksana А. Golubtsova
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Activation Parameters ◽  
Decomposition Kinetics ◽  
Mechanism Of Thermal Decomposition ◽  
Limiting Stage ◽  
Manometric Method ◽  
Steric Constant ◽  
Kinetics Of ◽  
Constant Activation Energy

Thermal decomposition kinetics of 1-substituted bis(1,1-dinitromethyl-3-Nitro-1,2,4-triazole- 5-yl) in solution of 1,3-dinitrobenzene is studied with manometric method under isothermal conditions. The limiting stage of thermal decomposition is homolytic break of C-NO2 bond in gem-dinitromethyl group; activation parameters of this stage are calculated. The reactivity of investigated compounds is analyzed. Correlation dependences between logarithm of rate constant, activation energy and steric constant of substituent R are obtained

THE KINETICS OF THE DECOMPOSITION REACTIONS OF THE LOWER PARAFFINS: VII. THE NITRIC OXIDE INHIBITED DECOMPOSITION OF ETHANE

1940 ◽  
Vol 18b (11) ◽  
pp. 351-357 ◽  
Author(s):  
E. W. R. Steacie ◽  
Gerald Shane
Keyword(s):  
Nitric Oxide ◽  
Activation Energy ◽  
Thermal Decomposition ◽  
Free Radical ◽  
Radical Chain ◽  
Decomposition Reactions ◽  
Rearrangement Mechanism ◽  
Chain Lengths ◽  
Kinetics Of

An investigation has been made of the nitric oxide inhibited thermal decomposition of ethane. Apparent chain lengths of 2.4 to 5 are found at temperatures from 640° to 565 °C. The activation energy of the inhibited reaction is found to be 77.3 Kcal. The results are discussed and it is concluded that the thermal decomposition of ethane proceeds mainly by a rearrangement mechanism and that free-radical chain mechanisms for the ethane decomposition are untenable.

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.

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 kinetics of the thermal decomposition of normal paraffin hydrocarbons - V. Order of reaction over extended ranges of pressure

1952 ◽  
Vol 214 (1116) ◽  
pp. 20-35 ◽  
Keyword(s):  
Activation Energy ◽  
Reaction Order ◽  
Initial Pressure ◽  
Important Change ◽  
Second Order ◽  
Relative Probability ◽  
First Order ◽  
Molecular Reaction ◽  
Single Transition ◽  
Kinetics Of

Previous papers have provided evidence that the decomposition of a paraffin reduced to its limiting rate by nitric oxide is a molecular reaction. This reaction has an unusual pressure dependence, which has now been studied over a wider range, namely, up to 1600 mm, and down to 0⋅1 mm. In the higher part of the pressure range the reaction order changes from nearly the second to the first with increase in the initial pressure, as now confirmed by extended measurements on n -butane and n -pentane. In the lower part of the range another transition from second order to first with rise of pressure can be found, and is here shown by measurements on ethane, propane, n -butane, n -pentane and n -hexane. Thus with higher normal paraffins the reaction order is the second at the lowest pressure, decreases to the first, increases again towards the second and finally returns to the first at the highest pressure. Where this behaviour is shown the activation energy is also a function of the pressure. The activation energy for ethane is not a function of the pressure and, correspondingly, there is here a single transition from the second order at the lowest pressure to the first order at about 400 mm and up to at least 1600 mm. Over the range of pressure where the composite behaviour is observed, mass spectrometer analysis of the butane products reveals no important change in the relative probability of rupture at the C 1-2 and C 2-3 linkages respectively. In the region of the lower pressures, however, some of the primarily formed ethane splits to give ethylene and hydrogen more rapidly than can be accounted for by the decomposition rate of ethane as directly determined for comparable conditions.

scholarly journals STUDIES ON THE PERVANADIUM COMPLEX

1961 ◽  
Vol 39 (6) ◽  
pp. 1174-1183 ◽  
Author(s):  
G. A. Dean
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Acid Solution ◽  
Anionic Complex ◽  
Cationic Complex ◽  
Kcal Mole ◽  
Decomposition Products ◽  
First Order ◽  
Discrete Variations ◽  
Kinetics Of

The 'pervanadium complex' is investigated in a general manner. The kinetics of its thermal decomposition in acid solution are shown to be first order with respect to pervanadium, the apparent activation energy is 26.5 ± 1.0 kcal/mole, and possible mechanisms are suggested. The effect of various acids upon the nature of the decomposition products is determined: almost quantitative yields of vanadium (V) or vanadium (IV) are obtained in very dilute or concentrated acid, respectively. Spectrophotometric studies indicate that in acid solution two separate complexes exist: a red (1:1) cationic complex and a yellow (1:2) anionic complex. The stoichiometry of the equilibrium between the two complexes in solutions of sulphuric acid is investigated by a method of 'discrete variations'. The equilibrium could be described by[Formula: see text]where Kr/y = 2.2 ± 0.2 at 22 °C. The anion is shown to play an important part in determining the nature of the pervanadium complex.

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