Reaction of carbon atoms, C (2p2, 3P) with C3H4 (allene and methylacetylene), C3H6 (propylene) and C4H8 (trans-butene): Overall rate constants and atomic hydrogen branching ratios.

Abstract

The multichannel C + allene, methylacetylene, propylene and trans-butene reactions were studied, at room temperature, in a low-pressure fast-flow reactor. Carbon atoms were obtained from the reaction of CBr₄ with potassium atoms. The overall rate constants were found to be (2.7 ± 0.5) × 10⁻¹⁰, (2.9 ± 0.4) × 10⁻¹⁰, (2.6 ± 0.4) × 10⁻¹⁰, and (1.9 ± 0.6) × 10⁻¹⁰ cm³ molecule⁻¹ s⁻¹, respectively. The absolute atomic hydrogen branching ratios have been measured by resonance fluorescence in the vacuum ultraviolet: H (C + C₃H₄ (allene)) = 1.00_−0.06^+0.00, H (C + C₃H₄ (methylacetylene)) = 0.85 ± 0.06, H (C + C₃H₆ (propylene)) = 0.51 ± 0.08, H (C + C₄H₈ (trans-butene)) = 0.33 ± 0.08.