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

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 H<SUB>2</SUB>O molecular elimination channels. The CH<SUB>3</SUB>CHO formed by HX elimination is chemically active and undergoes secondary decomposition resulting in the formation of CH<SUB>4</SUB>, C<SUB>2</SUB>H<SUB>6</SUB>, and C<SUB>2</SUB>H<SUB>4</SUB>. A detailed kinetic simulation indicates that the formation of C<SUB>2</SUB>H<SUB>4</SUB> could not be quantitatively explained as arising exclusively from secondary CH<SUB>3</SUB>CHO decomposition. Contributions from primary radical processes need to be considered to explain C<SUB>2</SUB>H<SUB>4</SUB> quantitatively. Ab initio calculations on HX and H<SUB>2</SUB>O elimination reactions from the haloethanols at HF, MP2, and DFT levels with various basis sets up to 6/311++Gare<SUP>∗∗</SUP> reported. It is pointed out that due to strong correlations between A and Ea, comparison of these two parameters between experimental and theoretical results could be misleading