AbstractThe rate coefficients for the gas‐phase pyrolyses of a series of structurally related secondary acetates have been measured in a static system over the temperature range of 289.1–359.5°C and the pressure range 50.0–203.0 torr. The temperature dependence of the rate coefficients is given by the following Arrhenius equations: for 3‐hexyl acetate, logk1(s−) = (12.12 ± 0.33) − (176.1 ± 3.9)kJ/mol/2.203RT; for 5‐methyl‐3‐hexyl acetate, logk1(s−) = (13.17 ± 0.20) − (186.2 ± 2.3)kJ/mol/2.303RT; and for 5,5‐dimethyl‐3‐hexyl acetate, logk1(s−) = (12.70 ± 0.19) − (177.4 ± 2.2)kJ/mol/2.303RT. The direction of elimination of these esters has shown from the invariability of olefin distributions at different temperatures and percentages of decomposition that steric hindrance is a determining factor in the eclipsedcisconformation. Moreover, a more detailed analysis indicates that the greater the alkyl–alkyl interaction, the less favored the elimination tends to be. Otherwise, an increase of alkyl–hydrogen interaction caused steric