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Kinetics and Products of Propargyl (C3H3) Radical Self-Reactions and Propargyl-Methyl Cross-Combination Reactions



Askar Fahr, A Nayak


Propargyl (HC=C-CH2) and methyl radicals were produced through the 193 nm excimer laser photolysis of mixtures of C3H3Cl/He and CH3N2CH3/He respectively. The gas chromatographic/mass spectrometric [GC/MS] product analysis were employed to characterize and quantify the major reaction products. The rate constants for propargyl radical self- reactions and propargyl-methyl cross-combination reactions were determined through kinetic modeling and comparative rate determination methods. The major products of the propargyl radical combination reactions, at room temperature and total pressure of about 6.7 kPa (50 Torr), consisted of three C6H6 isomers with 1,5-hexadiyne (CH{identical with}C-CH2-CH2-C{identical with}.about 60%): 1.2 hexadiene-5ne (CH2{identical with}C{identical with}C-CH2-C{identical with}CH. About 25%) and a third isomer of C6H6({difference}15%). Which has not yet been with uncertainty identified as being the major products. The rate constant determinations, in the propargyl-methyl mixed radical system, yielded a value of (4.0 0.4)x10-11 cm3molecule-1s-1 for propargyl radical combination reactions and a rate constant of (1.5 0.3) x 10-10 cm3molecule-1s-1 for propargyl - methyl cross combination reactions. The products of methyl-propargyl cross-combination reactions were two isomers of C4H6, 1 butyne (about 60%) and 1.2 butyne (about 40%).
International Journal of Chemical Kinetics


combination reactions, kinetics, methyl radical, product analysis, propargyl radical, rate constant


Fahr, A. and Nayak, A. (2000), Kinetics and Products of Propargyl (C<sub>3</sub>H<sub>3</sub>) Radical Self-Reactions and Propargyl-Methyl Cross-Combination Reactions, International Journal of Chemical Kinetics (Accessed July 22, 2024)


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Created January 1, 2000, Updated February 17, 2017