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 DECOMPOSITIONS OF THE LOWER PARAFFINS: V. THE NITRIC OXIDE INHIBITED DECOMPOSITION OF n-BUTANE

1940 ◽  
Vol 18b (1) ◽  
pp. 1-11 ◽  
Author(s):  
E. W. R. Steacie ◽  
H. O. Folkins
Keyword(s):  
Nitric Oxide ◽  
Thermal Decomposition ◽  
Free Radical ◽  
High Pressures ◽  
Free Radical Processes ◽  
Temperature Range ◽  
Radical Recombination ◽  
Radical Processes ◽  
Kinetics Of ◽  
Good Agreement

A detailed investigation of the inhibition by nitric oxide of the thermal decomposition of n-butane has been carried out over the temperature range 500° to 550 °C.In all cases it was found that inhibition decreased with increasing butane concentration. This suggests that radical recombination occurs in the normal decomposition by ternary collisions with butane molecules acting as third bodies.The activation energies of the normal and inhibited reactions have been determined. For high pressures the two values are in good agreement, viz., 58,200 and 57,200 cal. per mole respectively. The products of the inhibited reaction were also found to be the same as those of the normal reaction.It is concluded that free radical processes predominate, involving comparatively short chains.

THE KINETICS OF THE DECOMPOSITION REACTIONS OF THE LOWER PARAFFINS: IV. THE ROLE OF FREE RADICALS IN THE DECOMPOSITION OF n-BUTANE

1939 ◽  
Vol 17b (3) ◽  
pp. 105-120 ◽  
Author(s):  
E. W. R. Steacie ◽  
H. O. Folkins
Keyword(s):  
Nitric Oxide ◽  
Ethylene Oxide ◽  
Complete Suppression ◽  
Radical Chain ◽  
Decomposition Reactions ◽  
Maximum Inhibition ◽  
A Chain ◽  
Kinetics Of ◽  
Oxide Inhibition

An investigation has been made of the inhibition of free radical chain processes in the decomposition of n-butane by the addition of nitric oxide. The method was to initiate chains in butane at low temperatures by means of ethylene oxide, and then to investigate the efficiency of nitric oxide in suppressing these chains.It was found that nitric oxide is not completely efficient as a chain breaker, inasmuch as sensitization by ethylene oxide persisted in the presence of large amounts of nitric oxide. It is therefore concluded that maximum inhibition of organic decomposition reactions by nitric oxide does not in all cases correspond to complete suppression of chains, and hence the real chain length in such reactions may be greater than that inferred from the results of the nitric oxide inhibition method.

THE KINETICS OF THE THERMAL DECOMPOSITION OF VINYL ISOPROPYL ETHER

1953 ◽  
Vol 31 (4) ◽  
pp. 418-421 ◽  
Author(s):  
Arthur T. Blades
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Free Radical ◽  
Ethyl Ether ◽  
Close Agreement ◽  
Flow System ◽  
Isopropyl Ether ◽  
Radical Decomposition ◽  
A Minor ◽  
Kinetics Of

The thermal decomposition of vinyl isopropyl ether in the presence of toluene has been studied in a flow system in the temperature range 447–521 °C. In this range, the data indicate a purely intramolecular decomposition into propylene and acetaldehyde, the activation energy for the reaction being in close agreement with that found for the decomposition of vinyl ethyl ether. At 570 °C. a minor free radical decomposition of the ether becomes apparent. Some qualitative studies of the decomposition of vinyl isobutyl ether are also reported.

The kinetics of the thermal decomposition of normal paraffin hydrocarbons IV. Modes of rupture of the carbon chain

1951 ◽  
Vol 208 (1094) ◽  
pp. 285-291 ◽  
Keyword(s):  
Nitric Oxide ◽  
Activation Energy ◽  
Carbon Chain ◽  
Relative Probability ◽  
Radical Chain ◽  
Energy Part ◽  
Molecular Reaction ◽  
Tentative Explanation ◽  
Kinetics Of ◽  
Radical Chain Reaction

The decomposition of a normal higher paraffin yields methane, ethane and propane in proportions which indicate approximately the relative probability of rupture of the carbon chain at various places. In the nitric oxide-inhibited reaction (by hypothesis, a molecular reaction) these proportions are found to be independent of temperature and pressure over ranges where marked changes would occur if the rupture of the various C—C bonds corresponded to processes of appreciably different activation energy. The variation with pressure of the overall activation energy (part III) is therefore not associated with these various modes of rupture of the molecule. The relative probability of rupture decreases with distance from the end of the carbon chain, methane and ethane being the predominant saturated products. A tentative explanation is suggested, which depends upon the electronic symmetry of the structures of the two lowest paraffins. The proportions of the products formed in the radical chain reaction and in the reaction inhibited by nitric oxide (molecular reaction) are very similar, and an explanation of this fact is offered.

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 THE DECOMPOSITION REACTIONS OF THE LOWER PARAFFINS: VI. ETHANE

1940 ◽  
Vol 18b (7) ◽  
pp. 203-216 ◽  
Author(s):  
E. W. R. Steacie ◽  
Gerald Shane
Keyword(s):  
Thermal Decomposition ◽  
Free Radical ◽  
Static Method ◽  
Point Of View ◽  
Temperature Range ◽  
Decomposition Reactions ◽  
Kinetics Of

The kinetics of the thermal decomposition of ethane have been investigated by the static method in the temperature range 565° to 640 °C. The reaction was found to be uninfluenced by surface. The rate of the reaction can be expressed by[Formula: see text]The products of the reaction are ethylene, hydrogen, and a small amount of methane and probably higher hydrocarbons.The reaction is discussed from the point of view of free radical mechanisms, and it is suggested that the results cast serious doubt on the validity of the Rice-Herzfeld mechanism and its modification by Küchler and Theile.

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.

Mechanism of the Pyrolysis of Acetylene

1971 ◽  
Vol 49 (13) ◽  
pp. 2199-2204 ◽  
Author(s):  
M. H. Back
Keyword(s):  
Free Radical ◽  
Chain Mechanism ◽  
Kinetic Characteristics ◽  
Radical Chain ◽  
Temperature Range ◽  
Decomposition Reactions ◽  
Radical Chain Mechanism ◽  
Initiation Reaction ◽  
Kinetics Of ◽  
Subsequent Addition

A free radical chain mechanism is presented to describe the kinetics of the pyrolysis of acetylene over the temperature range 700–2400 °K. The mechanism is based on the following initiation reaction[Formula: see text]and subsequent addition, abstraction, and decomposition reactions of the radicals involved are shown to account for the products observed and for the kinetic characteristics of the reaction.

Kinetics of the thermal reactions of ethylene. Part I

1968 ◽  
Vol 46 (14) ◽  
pp. 2415-2426 ◽  
Author(s):  
M. L. Boyd ◽  
T-M. Wu ◽  
M. H. Back
Keyword(s):  
Activation Energy ◽  
Molecular Weight ◽  
Free Radical ◽  
Induction Period ◽  
Pressure Range ◽  
Kcal Mole ◽  
Radical Chain ◽  
Thermal Reactions ◽  
Chain Polymerization ◽  
Kinetics Of

The pyrolysis of ethylene has been studied in the temperature range 500–600 °C and the pressure range 15–60 cm. The main products were ethane, propylene, butene, butadiene, and a polymer of molecular weight corresponding to C8 or higher. Small amounts of methane, butane, unsaturated C5, unsaturated C6, and benzene were also measured. Of the main products, propylene, butene, and butadiene showed an induction period, as long as several minutes at the lowest temperature. The order with respect to ethylene of ethane, propylene, and butene was close to two and the activation energy of the rates was approximately 40 kcal/mole. The results have been interpreted in terms of a free radical chain polymerization. It is suggested that the polymer formed is unstable and decomposes to yield the products for which an induction period was observed.

scholarly journals The detection and inhibition of free radical chain reactions

1942 ◽  
Vol 180 (982) ◽  
pp. 237-256 ◽  
Keyword(s):  
Nitric Oxide ◽  
Free Radical ◽  
Chemical Analysis ◽  
Diethyl Ether ◽  
Pressure Increase ◽  
Stationary States ◽  
Decomposition Rates ◽  
Radical Chain ◽  
Chain Reactions ◽  
Limiting Values

Part I. Comparison of nitric oxide and propylene as inhibitors The reduction by propylene of the rate of pressure increase in the decomposition of propaldehyde at 550° has been shown by chemical analysis to represent a true inhibition of the reaction, and not to be due n an important degree to an induced polymerization of the propylene. With propaldehyde and with diethyl ether the limiting values to which the decomposition rates are reduced by nitric oxide and by propylene respectively are the same, although much more propylene is required to produce a given degree of inhibition. From this it is concluded that the limiting rates are more probably those of independent non-chain processes, than those characteristic of stationary states where the inhibitor starts and stops chains with equal efficiency.

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