THE POLYMERIZATION OF ETHYLENE SENSITIZED BY ETHYL IODIDE

1956 ◽  
Vol 34 (1) ◽  
pp. 41-53 ◽  
Author(s):  
V. B. Sefton ◽  
D. J. Le Roy
Keyword(s):  
Thermal Decomposition ◽  
Mercury Vapor ◽  
Chain Termination ◽  
Ethyl Iodide ◽  
Predominant Formation ◽  
Equilibrium Processes ◽  
Ethyl Radicals ◽  
Radical Disproportionation

The polymerization of ethylene sensitized by the thermal decomposition of ethyl iodide in the presence of mercury vapor has been studied at 250°, 275°, and 300 °C. C14-labelled ethyl iodide was used in a number of experiments. The increase in the rate of decomposition of ethyl iodide in the presence of ethylene and the formation of butyl iodide are accounted for by equilibrium processes of the type RI + Hg = R + HgI. The important features of the reaction were established from the identity, quantity, and activity of the various products. The predominant formation of olefins is attributed to the isomerization and decomposition of large radicals. Very little of the butane is formed by the combination of ethyl radicals. Radical disproportionation is the most important chain termination step.

The mercury (63P1) photosensitized hydrogenation of ethylene. Kinetics of the reaction C2H5 + H2 = C2H6 + H

1968 ◽  
Vol 46 (20) ◽  
pp. 3275-3281 ◽  
Author(s):  
L. E. Reid ◽  
D. J. Le Roy
Keyword(s):  
Gas Phase ◽  
Molecular Hydrogen ◽  
Mercury Vapor ◽  
Experimental Conditions ◽  
Working Pressure ◽  
Extinction Coefficients ◽  
Secondary Reactions ◽  
Ethyl Radicals ◽  
Kinetics Of ◽  
Hydrogenation Of Ethylene

A quantitative study has been made of the reaction of ethyl radicals with molecular hydrogen in the gas phase in the temperature range 240 to 320 °C. The mercury (63Pi) photosensitized decomposition of hydrogen in the presence of ethylene was used to generate ethyl radicals. Extinction coefficients for the absorption of 2537 Å by mercury vapor were measured and Beer's law was shown to be obeyed under the experimental conditions used. The corrections required to allow for the nonuniformity of radical concentrations in the cell were small. After delineating the experimental conditions necessary to minimize secondary reactions, the rate constant (cm3 mole−1 s−1) for the reaction C2H5 + H2 = C2H6 + H was found to be given by log10k = 12.57 − 13.7/θ. Experiments in the presence of added carbon dioxide showed the absence of hot radical effects at the working pressure of 92 Torr of hydrogen.

High-temperature dissociation of ethyl radicals and ethyl iodide

2012 ◽  
Vol 44 (7) ◽  
pp. 433-443 ◽  
Author(s):  
Xueliang Yang ◽  
Robert S. Tranter
Keyword(s):  
High Temperature ◽  
Ethyl Iodide ◽  
Ethyl Radicals

Radiation-sensitized Thermal Cracking of n-Butane. I. Radical Reactions

1974 ◽  
Vol 52 (14) ◽  
pp. 2579-2589 ◽  
Author(s):  
Shingo Matsuoka ◽  
Takaaki Tamura ◽  
Keichi Oshima ◽  
Yunosuke Oshima
Keyword(s):  
Activation Energy ◽  
Main Chain ◽  
Thermal Cracking ◽  
Chain Termination ◽  
Chain Mechanism ◽  
Radical Chain ◽  
Chain Termination Reaction ◽  
Ammonia Addition ◽  
Ethyl Radicals ◽  
Cracking Products

The radiolysis of n-butane was investigated at temperatures ranging from 17 to 548 °C in both static and flow systems.It was concluded that in the radiation-sensitized thermal cracking region the main products, methane, ethane, ethylene, and propylene, were formed by a radical chain mechanism. The conclusion was reached from comparison with the thermal cracking products, the effect of ammonia addition, the dose rate dependence, and in particular the correlation between the temperature change of the type of the main chain-termination reaction and that of the activation energy of propylene formation. The value of the activation energy for propylene formation showed that the main chain-termination reaction at temperatures between 410 and 520 °C was a combination reaction of ethyl radicals. The major part of 1-butene, trans-2-butene, and cis-2-butene, formed in the chain region, was shown to result from the thermal decomposition of the chain carrying butyl radicals.Rate parameters for some of the reactions involved were calculated.

Pyrolysis of triethylgallium by the toluene carrier technique

1979 ◽  
Vol 57 (24) ◽  
pp. 3178-3181 ◽  
Author(s):  
Michellene C. Paputa ◽  
Stanley James W. Price
Keyword(s):  
Thermal Decomposition ◽  
Pressure Range ◽  
Hydrogen Abstraction ◽  
Significant Extent ◽  
Rate Determining Step ◽  
Surface Catalysis ◽  
Gas System ◽  
One Step ◽  
Gallium Hydride ◽  
Ethyl Radicals

The pyrolysis of triethylgallium has been studied in a toluene carrier gas system in the temperature range of 464.7 to 700.7 K and a pressure range of 0.82 to 3.73 kPa. From the data obtained from this work, the following mechanism for the thermal decomposition of the metal alkyl is proposed:[Formula: see text]where [1] is the rate determining step. After runs below 606 K were corrected for the contribution of a concurrent residual reaction, a least-squares analysis of experimental results from 567 to 651 K based on both product and residual alkyl analysis gave[Formula: see text]at 1.60 kPa.The rate constant, k1, is very slightly pressure-dependent as revealed by tests at 648.0 K (80% and 45% decomposition). Studies indicate there is no detectable surface catalysis effect. Similarly, no effect was observed for changes in concentration or contact time.The mechanism for the formation of polymeric gallium hydride in reaction [4] is not clearly defined and may consist of more than one step. Reaction [5] is slow but based on the C2H4:H2 ratio must occur to a significant extent (40–80%) during a run. Further decomposition occurs between runs, causing a build-up of H2 in the reaction vessel.Experimental data for the hydrogen abstraction by ethyl radicals from toluene[Formula: see text]yield the equation[Formula: see text]

THE THERMAL DECOMPOSITION OF ETHANE: PART I. INITIATION AND TERMINATION STEPS

1966 ◽  
Vol 44 (4) ◽  
pp. 505-514 ◽  
Author(s):  
M C. Lin ◽  
M. H. Back
Keyword(s):  
Thermal Decomposition ◽  
High Pressure ◽  
Rate Coefficients ◽  
First Order ◽  
Temperature Range ◽  
Order Rate ◽  
Ethyl Radical ◽  
Initiation Reaction ◽  
Ethyl Radicals

The rates of production of methane and butane in the pyrolysis of ethane have been measured over the temperature range 550–620 °C and at pressures of 40–600 mm. At high pressure the rates of formation of both products were first order in ethane, but below 200 mm the first-order rate coefficients decreased. The ratio of methane to butane was consistent with the interpretation that methane is a measure of the initiation reaction and that the combination and disproportionation of ethyl radicals is the main termination step. The order of the decomposition of the ethyl radical with respect to ethane varied between 0.38 and 0.59. The results are discussed in terms of the mechanism of the overall process.

PHOTOLYSIS OF 2, 2′, 4, 4′-TETRADEUTERODIETHYL KETONE

1951 ◽  
Vol 29 (12) ◽  
pp. 1092-1103 ◽  
Author(s):  
M. H. J. Wijnen ◽  
E. W. R. Steacie
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Diethyl Ketone ◽  
Temperature Range ◽  
A Value ◽  
Ethyl Radicals

The photolysis of CH3CD2COCD2CH3 has been studied over a temperature range from 25°C. to 365°C. The results confirm several features of the mechanism, previously proposed for the photolysis of diethyl ketone. It is concluded that disproportionation of ethyl radicals occurs by a "head to tail" mechanism. As activation energy for the reaction[Formula: see text]a value E4 = 8.7 kcal. was found. As activation energy for Reaction (5)[Formula: see text]a value of E5 = 11.7 kcal. was found. An activation energy of ∼ 17 kcal. is estimated for the thermal decomposition of the pentanonyl radical

Thermal decomposition of O-benzyl ketoximes; role of reverse radical disproportionation

2004 ◽  
Vol 2 (3) ◽  
pp. 415 ◽  
Author(s):  
Jessie A. Blake ◽  
Keith U. Ingold ◽  
Shuqiong Lin ◽  
Peter Mulder ◽  
Derek A. Pratt ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Radical Disproportionation
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