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

Published

January 1, 2000

Author(s)

Askar Fahr, A Nayak

Abstract

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%).

Citation

International Journal of Chemical Kinetics

Volume

32

Pub Type

Journals

Keywords

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

Citation

Fahr, A. and Nayak, A. (2000), Kinetics and Products of Propargyl (C₃H₃) Radical Self-Reactions and Propargyl-Methyl Cross-Combination Reactions, International Journal of Chemical Kinetics (Accessed April 25, 2024)