5291-90-7Relevant academic research and scientific papers
Shock Tube Study of Thermal Rearrangement of 1,5-Hexadiyne over Wide Temperature and Pressure Regime
Tranter, Robert S.,Tang, Weiyong,Anderson, Ken B.,Brezinsky, Kenneth
, p. 3406 - 3415 (2007/10/03)
The pyrolysis of 1,5-hexadiyne has been studied in a high-pressure single pulse shock tube to investigate the mechanisms involved in the production of benzene from propargyl radicals. Analysis of the reaction products by gas chromatography and matrix isolation Fourier transform infrared spectroscopy has positively identified six linear C6H6 species and two cyclic C6H6 species. Of these species cis-1,3-hexadien-5- yne and trans-1,3-hexadiene-5-yne have been unambiguously identified for the first time and provide vital information concerning a low-temperature route to benzene that does not involve the formation of fulvene; however, the data also provide support for two high-temperature paths from propargyl radicals to benzene via fulvene. Thus experimental evidence has been gained that supports two different routes to benzene formation. The mechanisms and rate coefficients that have been obtained in this work are discussed.
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.
Thermal Rearrangements, XXIII. - The Thermogram of a C6H6 Chemistry in the Temperature Range from 450 to 730 deg C
Zimmermann, Gerhard,Nuechter, Matthias,Remmler, Matthias,Findeisen, Matthias,Hopf, Henning,et al.
, p. 1747 - 1754 (2007/10/02)
The thermal isomerization of 1,5-hexadiyne (1) and its 2>-labeled derivative (1a) was studied in the temperature range 450 - 730 deg C and in the presence of different carrier gases (N2, H2, D2, N2/toluene).By detailed analysis (GC, GCMS, NMR) all volatile reaction products were identified and determined quantitatively by using hexafluorobenzene as an internal standard.The experimental data show clearly that the reaction products are formed by two different routes: (i) electrocyclization leading to dimethylene cyclobutene (3) at temperatures up to about 600 deg C and (ii) radical reaction leading to benzene (4) and pentafulvene (5) at temperatures above 550 deg C.Cyclopentadienylmethyl radicals are supposed to be the essential radical intermediates. - Key Words: Isomerization, thermal / Radicals / D-Labeling / 1,5-Hexadiyne / Pentafulvene / Rearrangement, homoallyl
