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The thermal reactions of CH{sub 3}

Conference ·
OSTI ID:10158685

The thermal reactions of CH{sub 3}-radicals have been investigated in reflected shock waves experiments at temperatures between 1224--2520 K. The fast dissociation of CH{sub 3}I served as the source of CH{sub 3}. Experiments were performed at three loading pressures with variations in [CH{sub 3}I]{sub 0}. H-atoms formed in the reaction, 2CH{sub 3} {yields} C{sub 2}H{sub 5} + H, were measured by the atomic resonance absorption spectrometric (ARAS) technique. The product ethyl radicals subsequently decompose to give a second H-atom and ethylene. A reaction mechanism was used to fit the data, and the resulting value for the rate constant was 5.25 {times} 10{sup {minus}11} exp({minus}7384 K/T) cm{sup 3} molecule{sup {minus}1} s{sup {minus}1}. This value is compared to earlier determinations. At higher temperatures, 2150--2520 K, the H-atom formation rate was dominated by CH{sub 3} thermal dissociation. With simulations, the rate constant for CH{sub 3} + Kr {yields} CH{sub 2} + H + Kr could be determined. The rate constant for this process is: k = 4.68 {times} 10{sup {minus}9} exp({minus}42506 K/T) cm{sup 3} molecule{sup {minus}1} s{sup {minus}1}. This result is compared to earlier experimental determinations and also to theoretical calculations using the semi-empirical Troe formalism.

Research Organization:
Argonne National Lab., IL (United States)
Sponsoring Organization:
USDOE, Washington, DC (United States)
DOE Contract Number:
W-31109-ENG-38
OSTI ID:
10158685
Report Number(s):
ANL/CHM/CP--81410; CONF-940711--16; ON: DE94013395
Country of Publication:
United States
Language:
English