Reactions of trifluoromethyl radicals. I. Hydrogen abstraction from dimethyl sulphide

1972 ◽  
Vol 25 (4) ◽  
pp. 803 ◽  
Author(s):  
NL Arthur ◽  
KS Yeo
Keyword(s):  
Hydrogen Atom ◽  
Rate Constant ◽  
Hydrogen Abstraction ◽  
Reverse Reaction ◽  
Thermochemical Data ◽  
Hydrogen Atom Abstraction ◽  
Dimethyl Sulphide ◽  
Temperature Range

Hydrogen atom abstraction from (CH3)2S by CF3 radicals has been studied in the temperature range 79-167�: (1) CF3 + CH3SCH3 ←→ CF3H + CH3SCH2 (-1) The rate constant, based on Ayscough's value of 1013.36cmS mol-l s-l for the recombination of CF3 radicals, is given by (k1 in cm3 mol-1 s-l, E in J mol-l): Logk1 = (12.05 � 0.02)-(28710 � 130)/2.303RT Combination of these results with thermochemical data gives a calculated value of log k-1 = 12.2 - 62600/2.303RT for the rate constant of the reverse reaction. ΔH�f(CH3SCH2) and S�(CH3SCH2) are estimated to be 155.6 kJ mol-l and 290 J K-l mol-1 respectively.

Reactions of methyl radicals. I. Hydrogen abstraction from dimethyl sulphide

1976 ◽  
Vol 29 (7) ◽  
pp. 1483 ◽  
Author(s):  
NL Arthur ◽  
M Lee
Keyword(s):  
Free Radicals ◽  
Rate Constant ◽  
Rate Constants ◽  
Hydrogen Abstraction ◽  
Reverse Reaction ◽  
Thermochemical Data ◽  
Methyl Radicals ◽  
Dimethyl Sulphide ◽  
Temperature Range

Hydrogen abstraction from (CH3),S and CH3COCH3 by CH3 radicals CH3+CH3SCH3 → CH4+CH3SCH2 CH3 + CH3COCH3 → CH4 + CH3COCH2 has been studied in the temperature range 120-245�. The rate constants, based on the value of 1013.34cm3 mol-l s-1 for the recombination of CH3 radicals, are given by (k in cm3 mol-1 s-1, E in kJ mol-1, R = 0.008314 kJ K-1 mol-1): logk1 = (11.62 � 0.08) ? (38.35 � 0.68)/2.303RT logk3 = (11.61 � 0.05) ? (40.48 � 0.46)/2.303RT Combination of the results for (1) with thermochemical data gives a calculated value of Logk-1 = (11.8 -63.7/2.303RT for the rate constant of the reverse reaction. The results for CH3+(CH3)2S are compared with all of the available data for hydrogen abstraction by free radicals from both sulphur-containing compounds, and molecules of the type (CH3)xM.

Reactions of trifluoromethyl radicals. II. Hydrogen abstraction from monochlorosilane

1973 ◽  
Vol 26 (6) ◽  
pp. 1269 ◽  
Author(s):  
NL Arthur ◽  
BR Harman
Keyword(s):  
Hydrogen Atom ◽  
Rate Constant ◽  
Experimental Error ◽  
Hydrogen Abstraction ◽  
Activation Energies ◽  
Hydrogen Atom Abstraction ◽  
Temperature Range ◽  
Average Value

Hydrogen atom abstraction from SiH3Cl by CF3 radicals ����������������� CF3 + SiH3Cl → CF3H+SiH2Cl������������������� (1) has been studied in the temperature range 69-168�. The rate constant, based on Ayscough's value of 1013.36 cm3 mol-1 s-1 for the recombination of CF3 radicals, is given by (k1 in cm3 mol-1 s-1, E in kJ mol-1): ������������������ logk1 = (12.38�0.06)-(25.72�0.41)/2.303RT At 400 K, the rate constant for CF3 + SiH3Cl is greater than the average value reported for CF3+SiHCl3 by a factor of 3.6. This is due to a difference in A factors since the activation energies are equal within experimental error.

HYDROGEN ATOM ABSTRACTION BY ETHYL-d5 RADICALS. PART I

1960 ◽  
Vol 38 (9) ◽  
pp. 1576-1589 ◽  
Author(s):  
P. J. Boddy ◽  
E. W. R. Steacie
Keyword(s):  
Hydrogen Atom ◽  
Hydrogen Abstraction ◽  
Deuterium Atom ◽  
Structural Features ◽  
Activation Energies ◽  
Hydrogen Atom Abstraction ◽  
Kcal Mole ◽  
Temperature Range ◽  
Exponential Factors ◽  
Ethyl Radicals

The photolysis of 3-pentanone-d10 has been used as a source of deuterated ethyl radicals and some of their hydrogen abstraction reactions studied over the temperature range 50–300 °C.The compounds neopentane, n-butane, and isobutane were chosen as representative of the basic structural features in the alkane series. The activation energies for abstraction [Formula: see text] are respectively 12.60 ± 0.7, 10.4 ± 0.75, and 8.9 ± 0.6 kcal/mole and the pre-exponential factors (log10(A8/A4)) are 0.300 ± 0.09, 0.082 ± 0.09, and −0.334 ± 0.066 where[Formula: see text]For abstraction of a deuterium atom from the ketone the values obtained are [Formula: see text] in agreement with previous investigations (1, 2).The value of the disproportionation to combination ratio for C2D5 radicals is 0.0985 ± 0.008 independent of temperature.

scholarly journals Hydrogen Abstraction from Dimethyl Sulfide by Trifluoromethyl Radicals

1979 ◽  
Vol 32 (9) ◽  
pp. 2077 ◽  
Author(s):  
NL Arthur ◽  
KS Yeo
Keyword(s):  
Rate Constant ◽  
Additional Data ◽  
Dimethyl Sulfide ◽  
Hydrogen Abstraction ◽  
Reverse Reaction ◽  
Thermochemical Data

Additional data are presented for hydrogen abstraction from (CH3)2,S by CF3 radicals CF3+(CH3)2S → CF3H+CH2SCH2 (1) leading to a revised value for the rate constant (k in cm3 mol-1 s-1, E in J mol-1): logk1 = (11�83�0�06)-(26910�450)/19.16T Combination of these results with thermochemical data gives a revised value of logk-1 = 11�9-61800/19�145Tfor the rate constant of the reverse reaction.

Arrhenius parameters for the reaction of propyl radicals with propane

1969 ◽  
Vol 47 (18) ◽  
pp. 3305-3311 ◽  
Author(s):  
R. E. Berkley ◽  
G. N. C. Woodall ◽  
O. P. Strausz ◽  
H. E. Gunning
Keyword(s):  
Hydrogen Atom ◽  
Thermodynamic Data ◽  
Reverse Reaction ◽  
Hydrogen Atom Abstraction ◽  
Arrhenius Parameters ◽  
Complicating Factors

The reaction of n-propyl radicals from the photolysis of azo-n-propane with propane has been studied and Arrhenius parameters for hydrogen atom abstraction relative to the recombination of n-propyl radicals determined. From the Arrhenius parameters obtained and the available thermodynamic data, the Arrhenius parameters of the reverse reaction, the hydrogen atom abstraction from propane by iso-propyl radicals, have been calculated.Some complicating factors in the photolysis of azopropane are discussed.

Influence of the double bond on the hydrogen abstraction reactions of methyl esters with hydrogen radical: an ab initio and chemical kinetic study

RSC Advances ◽  
2015 ◽  
Vol 5 (84) ◽  
pp. 68314-68325 ◽  
Author(s):  
Quan-De Wang ◽  
Weidong Zhang
Keyword(s):  
Double Bond ◽  
Hydrogen Atom ◽  
Ab Initio ◽  
Kinetic Study ◽  
Rate Constants ◽  
Methyl Esters ◽  
Hydrogen Abstraction ◽  
Chemical Kinetic ◽  
Hydrogen Atom Abstraction ◽  
Hydrogen Radical

This work reports a systematic ab initio and chemical kinetic study of the rate constants for hydrogen atom abstraction reactions by hydrogen radical on the isomers of unsaturated C6 methyl esters.

Reactions of methyl radicals. V. Hydrogen abstraction from hydrogen sulfide

1983 ◽  
Vol 36 (11) ◽  
pp. 2195 ◽  
Author(s):  
H Arican ◽  
NL Arthur
Keyword(s):  
Hydrogen Sulfide ◽  
Rate Constant ◽  
Hydrogen Abstraction ◽  
Methyl Radicals ◽  
Arrhenius Parameters ◽  
Temperature Range

Hydrogen abstraction from H2S by CH3 radicals, produced by the photolysis of azomethane, has been studied in the temperature range 334-432 K. The rate constant, based on the value 1013.34 cm3 mol-1 s-1 for the recombination of CH3 radicals, is given by log k4 = (11.00 � 0.01) - (8760 � 80)/19.145T where k4 is in cm3 mol-1 s-1 and E is in J mol-1. The previous data reported for this reaction are discussed and best values for its Arrhenius parameters are recommended. The results indicate that CH3 radicals react faster than CF3 radicals with H2S; this confirms the importance of polar effects in the hydrogen abstraction reactions of CF3 radicals.

Reaction of Acyclic Hydrocarbons Towards t-Butoxy Radicals. A Study of Hydrogen Atom Abstraction by Using the Radical Trapping Technique

1998 ◽  
Vol 51 (12) ◽  
pp. 1113 ◽  
Author(s):  
Peter Dokolas ◽  
Steven M. Loer ◽  
David H. Solomon
Keyword(s):  
Hydrogen Atom ◽  
Hydrogen Abstraction ◽  
Hydrogen Atom Abstraction ◽  
Aromatic Solvent ◽  
Radical Trapping ◽  
Sterically Demanding ◽  
Butoxy Radical ◽  
Hydrocarbon Solution ◽  
Acyclic Hydrocarbons

The reaction of 3-methylpentane and 2,4-dimethylpentane toward t-butoxy radicals has been investigated, in neat and benzene solutions, by using the radical trapping technique. Abstraction occurs principally from the tertiary and secondary C-H reaction sites of 3-methylpentane and the tertiary position of 2,4-dimethylpentane. The tertiary and in particular secondary C-H reaction sites of 2,4-dimethylpentane are shown to be considerably less susceptible towards t-butoxy radical facilitated abstraction compared with the equivalent reaction sites of 3-methylpentane. As a result, the latter is three times as reactive as 2,4-dimethylpentane as a neat hydrocarbon solution and seven times as reactive in a diluted mixture of benzene. Diferences in selectivity and rate of hydrogen abstraction, between the substrates, are interpreted in terms of non-bonding interactions retarding t-butoxy radicals from approaching sterically demanding C-H reaction sites. The selectivity from 3-methylpentane is solvent-insensitive whereas abstraction from 2,4-dimethylpentane is modified in benzene. Further, the rate of hydrogen abstraction, from either substrate, to t-butoxy radical β-scission is considerably smaller in benzene. Both observations are interpreted in terms of t-butoxy radical solvation by the aromatic solvent.

Ab initio kinetics studies of hydrogen atom abstraction from methyl propanoate

2016 ◽  
Vol 18 (6) ◽  
pp. 4594-4607 ◽  
Author(s):  
Ting Tan ◽  
Xueliang Yang ◽  
Yiguang Ju ◽  
Emily A. Carter
Keyword(s):  
Hydrogen Atom ◽  
Ab Initio ◽  
Hydrogen Abstraction ◽  
Hydrogen Atom Abstraction ◽  
Kinetics Studies ◽  
Kinetics Of ◽  
Methyl Propanoate

The kinetics of hydrogen abstraction by five radicals (H, CH3, O(3P), OH, and HO2) from a biodiesel surrogate, methyl propanoate (MP), is theoretically investigated.

Kinetics of the reaction C2H5 + H2 → C2H6 + H from 1111-1200 K

1982 ◽  
Vol 60 (24) ◽  
pp. 3039-3048 ◽  
Author(s):  
J.-R. Cao ◽  
M. H. Back
Keyword(s):  
Rate Constant ◽  
Equilibrium Concentration ◽  
Reverse Reaction ◽  
Elementary Reaction ◽  
Hydrogen Atoms ◽  
Temperature Range ◽  
Lower Temperature ◽  
Kinetics Of ◽  
Rate Controlling Step ◽  
Hydrogenation Of Ethylene

A system for the measurement of the rate constant for the elementary reaction[Formula: see text]in the temperature range 1111–1200 K is described and is based on the thermal production of an equilibrium concentration of hydrogen atoms. In a mixture of hydrogen with about 10 ppm ethylene this reaction is the rate-controlling step in the hydrogenation of ethylene. The product ethane undergoes rapid secondary dissociation and the final product is methane. The values obtained in the present work, which are represented by the following expression,[Formula: see text](R = 1.987 cal mol−1 deg−1) are compared to those obtained at lower temperature (820–350 K) and to those calculated from measurements of the reverse reaction.

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