Thermal Decomposition of 1-Butyne in Shock Waves

Article abstract of DOI:10.1002/kin.550270403

1-Butyne diluted with Ar was heated behind reflected shock waves over the temperature range of 1100 - 1600 K and the total density range of 1.36*10^-5 - 1.75*10^-5 mol/cm³.Reaction products were analyzed by gas-chromatography.The progress of the reaction was followed by IR laser kinetic absorption spectroscopy.The products were CH4, C2H2, C2H4, C2H6, allene, propyne, C4H2, vinylacetylene, 1,2-butadiene, 1,3-butadiene, and benzene.The present data were successfully modeled with a 80 reaction mechanism. 1-Butyne was found to isomerize to 1,2-butadiene.The initial decomposition was dominated by 1-butyne -> C3H3 + CH3 under these conditions.Rate constant expressions were derived for the decomposition to be k₇ = 3.0*10¹⁵ exp(-75800 cal/RT) s^-1 and for the isomerization to be k₄ = 2.5*10¹³ exp(-65000 cal/RT) s^-1.The activation energy 75.8 kcal/mol was cited from literature value and the activation energy 65 kcal/mol was assumed.These rate constant expressions are applicable under the present experimental conditions, 1100 - 1600 K and 1.23 - 2.30 atm.