A Kinetic Determination of the Dissociation Energy of the C—O Bond in Anisole

1975 ◽  
Vol 53 (22) ◽  
pp. 3330-3338 ◽  
Author(s):  
S. Paul ◽  
M. H. Back
Keyword(s):  
Rate Constant ◽  
Dissociation Energy ◽  
Stabilization Energy ◽  
Phenoxy Radical ◽  
Methyl Radicals ◽  
Kinetic Determination ◽  
First Order

The rate of dissociation of anisole into phenoxy and methyl radicals has been measured using a toluene scavenging technique. The rate was measured by the production of methane over the range of temperature 720−795 K and was shown to be first order in anisole concentration and homogeneous. The rate constant, expressed in the Arrhenius form, was[Formula: see text]The dissociation energy, D298(C6H5O—CH3), therefore equals 57 ± 2 kcal/mol, giving ΔHf(C6H5O) = 5 kcal/mol. The stabilization energy of the phenoxy radical is discussed.

Vulcameter Determination of Best Cure

1965 ◽  
Vol 38 (4) ◽  
pp. 757-768 ◽  
Author(s):  
S. D. Gehman ◽  
F. S. Maxey ◽  
S. R. Ogilby
Keyword(s):  
Rate Constant ◽  
Work Load ◽  
Service Performance ◽  
Stress Strain ◽  
First Order ◽  
Testing Laboratories ◽  
Physical Testing ◽  
Strain Testing ◽  
Minimum Number

Abstract Using a continuous cure curve to select a minimum number of stepped cures, it should be possible to vulcanize and test fewer sheets to determine best cure. This procedure is attractive for its potential of expediting the output of physical testing laboratories and especially for reducing the work load of stress-strain testing. Cure curves recorded with the Vulcameter approximated first-order reactions. Equations were derived to calculate the final force and rate constant from recorded force values without carrying the reaction to completion. A chart is suggested to assist in calculating the rate constant. Time for a given fractional rise in force depends only on the rate constant so that a chart for obtaining it is relatively simple. Experience and correlation with service performance in selecting best cures is emphasized. 95% rise times from Vulcameter curves were compared with conventionally selected best cures for a wide variety of compounds. Indications are that experience with the method might reduce the number of test-sheet cures to determine optimum stress-strain properties to one, two, or three depending upon the compound and the exactness required.

The CH 2 : CH.CH 2 —CH 3 bond dissociation energy and the heat of formation of the allyl radical

1950 ◽  
Vol 202 (1069) ◽  
pp. 263-276 ◽  
Keyword(s):  
Bond Dissociation Energy ◽  
Dissociation Energy ◽  
Heat Of Formation ◽  
Methyl Radicals ◽  
Kcal Mole ◽  
Allyl Radical ◽  
First Order ◽  
Bond Dissociation ◽  
Benzyl Radicals ◽  
Thermal Stability Of

The pyrolysis of butene-1 was investigated by a flow technique, toluene being used as a carrier gas. It was found that butene-1 decomposed into allyl and methyl radicals according to the equation CH 2 : CH.CH 2 — CH 3 → CH 2 : CH.CH 2 + CH 3 . Methyl radicals were removed by reaction with toluene giving methane and benzyl radicals. The rate of the initial decomposition was measured by the rate of formation of methane. The decomposition was found to be a homogeneous first order gas reaction. The activation energy was calculated at 61.5 kcal./mole and it was identified with the CH 2 : CH.CH 2 — CH 3 bond dissociation energy. Taking D (CH 2 : CH.CH 2 —CH 3 ) at 61.5 kcal./mole we calculated from thermochemical data D (CH 2 : CH.CH 2 —H) at 76.5 kcal./mole and the heat of formation of allyl radical at + 30 kcal./mole. The fate of allyl radicals is discussed and the thermal stability of these is compared with that of benzyl radicals.

A method for the direct determination of the rate constants for radical-radical interactions in the gas phase II. The rate constant for the recombination of methyl radicals

1957 ◽  
Vol 243 (1232) ◽  
pp. 130-142 ◽  
Keyword(s):  
Gas Phase ◽  
Rate Constant ◽  
Room Temperature ◽  
Direct Determination ◽  
Theoretical Interpretation ◽  
Methyl Radicals ◽  
Gas Phase Reactions ◽  
A Value ◽  
Acetone Vapour

The technique outlined in part I of this paper has been employed to study the photo­sensitized decomposition of acetone vapour. A theoretical interpretation of the non-stationary state applied to non-chain photochemical gas phase reactions with second-order termination has been given and the effects of non-homogeneous absorption of radiation have been considered. A value has been obtained for the rate constant for the recombination of methyl radicals in the gas phase at room temperature.

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.

Kinetic Determination of Total Serum Protein with a Centrifugal Analyzer

1974 ◽  
Vol 20 (3) ◽  
pp. 392-394 ◽  
Author(s):  
Thomas R Koch ◽  
George F Johnson ◽  
Max E Chilcote
Keyword(s):  
Kinetic Analysis ◽  
Serum Protein ◽  
Analytical Method ◽  
Clinical Laboratory ◽  
Total Serum Protein ◽  
Total Serum ◽  
Kinetic Determination ◽  
First Order

Abstract A kinetic biuret assay of total serum protein on the "CentrifiChem" centrifugal analyzer is shown to be rapid, accurate, and reasonably precise, and accommodates the most desirable analytical method and standardization currently available. Kinetic analysis of compounds undergoing first-order reactions is a useful type of analysis that is of significant advantage to the clinical laboratory.

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