Erratum: The thermal decomposition of ethane. Part II. The unimolecular decomposition of the ethane molecule and the ethyl radical

1967 ◽  
Vol 45 (18) ◽  
pp. 2115-2115 ◽  
Author(s):  
M. C. Lin ◽  
M. H. Back
Keyword(s):  
Thermal Decomposition ◽  
Unimolecular Decomposition ◽  
Ethyl Radical ◽  
Ethane Molecule

Thermal decomposition of the ethyl radical

1967 ◽  
Vol 45 (22) ◽  
pp. 2795-2803 ◽  
Author(s):  
L. F. Loucks ◽  
K. J. Laidler
Keyword(s):  
Thermal Decomposition ◽  
Entire Range ◽  
Pressure Range ◽  
Heat Of Formation ◽  
Unimolecular Decomposition ◽  
Kcal Mole ◽  
Ethyl Radical ◽  
A Value ◽  
Kinetics Of ◽  
Best Fit

The kinetics of the thermal decomposition of the ethyl radical to give an ethylene molecule and a hydrogen atom were studied over the pressure range 4 to 650 mm Hg and the temperature range 400 to 500 °C; the mercury-photosensitized decomposition of ethane was used to generate the ethyl radical. The unimolecular decomposition of the ethyl radical was found to be pressure dependent over the entire range of pressures studied, with the order of reaction varying from 1.6 for the lowest pressures to 1.4 at the highest pressures. The extrapolated high-pressure and low-pressure rate constants for the decomposition of the ethyl radical are given by [Formula: see text] [Formula: see text]A best fit of the Kassel equation to the observed pressure dependence shows that s = 8 for this reaction. The results lead to a value of 98 1 kcal/mole for the bond dissociation energy D(C2H5—H). The heat of formation of the ethyl radical was calculated to be 30.0 and 26.2 kcal/mole for 0 °K and 25 °C respectively.

Mass spectrometric studies of chemical reactions in shock waves: the thermal decomposition of nitrous oxide

1969 ◽  
Vol 47 (4) ◽  
pp. 521-538 ◽  
Author(s):  
S. C. Barton ◽  
J. E. Dove
Keyword(s):  
Thermal Decomposition ◽  
Shock Waves ◽  
Rate Coefficient ◽  
Mass Spectrometric Study ◽  
Mass Spectrometric ◽  
Unimolecular Decomposition ◽  
Reflected Shock ◽  
Secondary Reactions ◽  
Gas Reactions ◽  
Collision Mechanism

Apparatus for the mass spectrometric study of rapid gas reactions in reflected shock waves is described. This apparatus has been applied to the thermal decomposition of 2% N2O in Kr at total gas concentrations of about 1.6 × 10−6 mole cm−3, in the temperature range 1800 to 2800 °K. The principal products of the reaction were found to be N2, O2, NO, and O. The rate coefficient for the unimolecular decomposition of N2O was calculated from the experimental data, and the rates of the secondary reactions between O and N2O were estimated. The possibility of the occurrence of a "weak collision" mechanism in the unimolecular reaction of N2O is discussed.

scholarly journals The homogeneous unimolecular decomposition of gaseous alkyl nitrites - IV—The decomposition of Iso -propyl nitrite

1935 ◽  
Vol 151 (874) ◽  
pp. 685-693 ◽  
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Pressure Change ◽  
Methyl Ethyl ◽  
Unimolecular Decomposition ◽  
Decomposition Rates ◽  
Straight Chain ◽  
Alkyl Nitrites ◽  
Branched Chain ◽  
Reaction Vessels

It has already been shown that the first three straight chain members of the nitrite homologous series, i. e ., methyl, ethyl, and n -propyl nitrites, have exhibited in their thermal decomposition the characteristics pertaining to homogeneous unimolecular reactions. This paper deals with the investigation carried out on iso -propyl nitrite decomposition. This member of the series is particularly interesting as it allows comparison to be made between a straight-chain and a branched-chain isomer. The effect of these chemical configurations on the activation energy and the decomposition rates can be very effectively studies as no complications enter into the reactions to confuse measurements. Experimental Reaction velocities were measured as before by observing the rate of pressure change in a system at constant volume. The reaction vessels were Pyrex glass bulbs with a capacity of about 125 cc. The apparatus was similar to that used in previous experiments. The connecting tubing was heated to 105° C to prevent any of the products of the reaction condensing out. Control and measurement of the temperature was carried out as before. The temperature could be maintained constant to within 0·25° C.

Ethyl radical initiated thermal decomposition of biacetyl

1976 ◽  
Vol 5 (2) ◽  
pp. 141-147 ◽  
Author(s):  
R. Schliebs ◽  
H. Knoll ◽  
K. Scherzer
Keyword(s):  
Thermal Decomposition ◽  
Ethyl Radical

The pyrolysis of n -butane

1962 ◽  
Vol 270 (1341) ◽  
pp. 267-284 ◽  
Keyword(s):  
Free Radical ◽  
Rate Constant ◽  
Analytical Study ◽  
Radical Mechanism ◽  
Unimolecular Decomposition ◽  
Ethyl Radical ◽  
Free Radical Mechanism ◽  
Quantitative Account ◽  
Kinetic Features

A detailed analytical study of the formation of the products of the pyrolysis of n-butane in the temperature range 420 to 530 °C and at initial pressures between 10 and 150 mm Hg has been carried out. A free-radical mechanism incorporating that originally proposed by Rice is shown to give an excellent quantitative account of the reactions occurring Rate parameters for some of the reactions involved have been calculated. The unimolecular decomposition of the ethyl radical is shown to be in its pressure dependent region throughout the range of conditions employed, and the fall-off of the rate constant with pressure is shown to be well described by the classical theory of Kassel. The important role of the ethyl radical in determining the kinetic features of paraffin pyrolyses is outlined.

Mass spectrometric studies of chemical reactions in shock waves. Part II. The thermal decomposition of diazomethane

1970 ◽  
Vol 48 (23) ◽  
pp. 3623-3634 ◽  
Author(s):  
J. E. Dove ◽  
J. Riddick
Keyword(s):  
Mass Spectrometry ◽  
Thermal Decomposition ◽  
Shock Waves ◽  
Vibrational Energy ◽  
Mass Spectrometric ◽  
Unimolecular Decomposition ◽  
Vibrationally Excited ◽  
Flight Mass Spectrometry ◽  
Concentration Changes ◽  
Products Of Reaction

The thermal decomposition of CH2N2, highly diluted in Kr, has been studied in shock waves by using time-of-flight mass spectrometry to follow concentration changes in the reacting gas. Observations were made at pressures 45 to 95 Torr and temperatures 820 to 1200°K. The principal products of reaction are C2H4, C2H2, and N2. The primary step appears to be a second order unimolecular decomposition of CH2N2 into CH2 and N2; for this step, log k = (9.61 ± 0.21) − (15 800 ± 1 000)/2.303RT(cal mole−1 and cm3 mole s units.) Some decomposition of CH2N2 into HCN and NH is also indicated. The formation of C2H2 is believed to occur through vibrationally excited C2H4, formed by reaction between CH2 and CH2N2. Calculations using the R.R.K.M. theory indicate that 50 + 10% of the energy of this reaction appears as vibrational energy of the product C2H4.

Investigation of the Thermal Decomposition of Ketene and of the Reaction CH2 + H2 ⇔ CH3 + H

2001 ◽  
Vol 215 (12) ◽  
Author(s):  
G. Friedrichs ◽  
H.Gg. Wagner
Keyword(s):  
Thermal Decomposition ◽  
Low Temperature ◽  
Shock Waves ◽  
High Temperatures ◽  
Frequency Modulation ◽  
Decomposition Reaction ◽  
Activation Energies ◽  
Unimolecular Decomposition ◽  
First Time ◽  
Singlet Methylene

Using frequency modulation (FM) spectroscopy singlet methylene radicals have been detected for the first time behind shock waves. The thermal decomposition of ketene served as source for metylene radicals at temperatures from 1905 to 2780 K and pressures around 450 mbar. For the unimolecular decomposition reaction, (1) CHAs a first study of a methylene reaction at high temperatures by diretly tracing methylene the reaction of methylene with hydrogen, (8 + 9)log(A comparison with low temperature literature data and the systematics of activation energies of triplet methylene reactions allowed a consistent description of singlet and triplet contributions and of the forward and reverse reaction.

REACTION OF DEUTERIUM ATOMS WITH ETHANE—MECHANISM OF METHANE EXCHANGE

1958 ◽  
Vol 36 (6) ◽  
pp. 983-989 ◽  
Author(s):  
R. Berisford ◽  
D. J. Le Roy
Keyword(s):  
Methane Molecule ◽  
Methane Formation ◽  
Methyl Radicals ◽  
Third Body ◽  
Ethyl Radical ◽  
Ethane Molecule ◽  
Body Concentration

The reaction of deuterium atoms with ethane has been studied at 25 °C. by the method of mercury (3P1) photosensitization. Methane formation takes place by the addition of D atoms to methyl radicals in the presence of a third body. From the dependence of methane exchange on third-body concentration the lifetime of the excited methane molecule is estimated to be of the order of 10−9 sec. The lifetime of the excited ethane molecule formed by the addition of a D atom to an ethyl radical is estimated to be considerably less than 10−9 sec.

Importance of heterogeneous termination in the pyrolysis of ethane

1967 ◽  
Vol 45 (24) ◽  
pp. 3165-3167 ◽  
Author(s):  
M. C. Lin ◽  
M. H. Back
Keyword(s):  
Thermal Decomposition ◽  
Ethyl Radical ◽  
Termination Process

It is shown that the increase in the order of the thermal decomposition of ethane that is observed below about 200 mm is partly the result of the changes in the order of the unimolecular dissociations of ethane and the ethyl radical that occur in the same range of pressures, and partly the result of the increasing importance of a heterogeneous termination process as the pressure is lowered.

THE THERMAL DECOMPOSITION OF ETHANE: PART II. THE UNIMOLECULAR DECOMPOSITION OF THE ETHANE MOLECULE AND THE ETHYL RADICAL

1966 ◽  
Vol 44 (20) ◽  
pp. 2357-2367 ◽  
Author(s):  
M. C. Lin ◽  
M. H. Back
Keyword(s):  
High Pressure ◽  
Rate Constant ◽  
Order Rate Constant ◽  
Methyl Radicals ◽  
Unimolecular Decomposition ◽  
First Order ◽  
Order Rate ◽  
Ethyl Radical ◽  
Lower Temperature ◽  
Ethyl Radicals

The rate of the elementary dissociation of ethane into two methyl radicals has been measured in its pressure-dependent region at temperatures from 913–999 °K and at pressures from 1–200 mm. The high-pressure first-order rate constant obtained by extrapolation was in agreement with that obtained at lower temperatures,[Formula: see text]Comparison with calculated Kassel curves showed that the best fit of the data was obtained with the Kassel parameter s = 12 ± 1. The high-pressure first-order rate constant for the decomposition of the ethyl radical was obtained by extrapolation of the data reported in Part I, assuming the rate constant for combination of ethyl radicals is independent of temperature.[Formula: see text]From the measured constant for the dissociation of ethane, the rate constant for the combination of methyl radicals was calculated and compared with the values measured in a lower temperature region. Differences in the values of the rate constants and in the shapes of the unimolecular falloff curves are discussed.

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