33142-15-3Relevant articles and documents
Pressure and Temperature Effects on Product Channels of the Propargyl (HC≡CCH2) Combination Reaction and the Formation of the First Ring
Howe, Pui-Teng,Fahr, Askar
, p. 9603 - 9610 (2007/10/03)
The mechanism for formation of aromatic and polyaromatic hydrocarbons and soot in combustion processes is still far from being well understood. The formation of the first aromatic ring, particularly benzene, is thought to be a critical step in soot formation mechanisms and has been the subject of continuing interest. Experimental results on the nature and the relative yields of the final products of the propargyl combination, C3H3 + C3H3 → C6H6 (1) were presented. Propargyl radicals, for most experiments, were generated by the 248 nm excimer laser photolysis of propargyl bromide. Five isomeric C6H6 final products were detected including 1,5-hexadiyne, fulvene, dimethylenecyclobutene, and benzene. The formation of dimethylenecyclobutene and benzene from the propargyl combination reaction was significantly more efficient than previously predicted. The relative yield of fulvene was less than those of dimethylenecyclobutene and benzene.
Kinetics and products of propargyl (C3H3) radical self-reactions and propargyl-methyl cross-combination reactions
Fahr, Askar,Nayak, Akshaya
, p. 118 - 124 (2007/10/03)
Propargyl and methyl radicals were produced through the 193-nm excimer laser photolysis of mixtures of C3H3Cl/He and CH3N2CH3/He, respectively. Gas chromatographic and mass spectrometric (GC/MS) product analyses 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 reaction, at room temperature and total pressure of about 6.7 kPa (50 Torr) consisted of three C6H6 isomers. The rate constant determination in the propargyl-methyl mixed radical system yielded a value of (4.0±0.4)×10-11 cm3 molecule-1 s-1 for propargyl radical combination reactions and a rate constant of (1.5±0.3)×10-10 cm3 molecule-1 s-1 for propargyl-methyl cross-combination reactions. The products of the methyl-propargyl cross-combination reactions were two isomers of C4H6, 1-butyne (about 60%) and 1,2-butadiene (about 40%).
Formation of C6H6 Isomers by Recombination of Propynyl in the System Sodium Vapour/Propynylhalide
Alkemade, U.,Homann, K. H.
, p. 19 - 34 (2007/10/02)
2-Propynyl radicals (C3H3) were generated from the respective chloride or bromide by the reaction Na + C3H3X -> C3H3 + NaX in a low-pressure flow reactor fed by multislit-diffusion burner.The temperature range was 623 to 673 K and total pressures of 300 and 600 Pa were applied.Analyses were performed by nozzle beam/mass spectrometry and by gas chromatography/mass spectrometry.The rate constants of the primary reactions were determined as k(Na + C3H3Cl) = 1.6E13 and k(Na + C3H3Br) = 7.8E13 cm3 mol-1 s-1, independent of temperature within the above range.The overall recombination rate constant of 2-propynyl was found to be 3.4E13 cm3 mol-1 s-1.The recombination products of propynyl were 1,5-hexadiyne, 1,2-hexadien-5-yne and 1,2,4,5-hexatetraene.Besides these direct products also 1,3-hexadien-5-yne and benzene were detected in relatively high yields which decreased with increasing pressure.A reaction mechanism via a propynyl-cyclopropene intermediate by which the chemically activated primary recombination products can rearrange to benzene and 1,3-hexadien-5-yne is discussed. - Keywords: Reaction kinetics / Hydrocarbon radicals / Sodium reactions / Benzene formation
