Thermal decomposition of haloethanols: single pulse shock tube and ab initio studies

Abstract

This paper reports single pulse shock tube and ab initio studies on thermal decomposition of 2-fluoro and 2-chloroethanol at T=1000–1200 K. Both molecules have HX (X = F/Cl) and H₂O molecular elimination channels. The CH₃CHO formed by HX elimination is chemically active and undergoes secondary decomposition resulting in the formation of CH4, C₂H₆, and C₂H₄. A detailed kinetic simulation indicates that the formation of C₂H₄ could not be quantitatively explained as arising exclusively from secondary CH₃CHO decomposition. Contributions from primary radical processes need to be considered to explain C₂H₄ quantitatively. Ab initio calculations on HX and H₂O elimination reactions from the haloethanols at HF, MP2, and DFT levels with various basis sets up to 6/311++G^**are reported. It is pointed out that due to strong correlations between A and E_α, comparison of these two parameters between experimental and theoretical results could be misleading.