The kinetics of the reactions of Cl atoms with three unsaturated carbonyl compounds at 298 K and atmospheric pressure were investigated for the first time using the GC-FID technique. Rate coefficients (in cm(3) molecule (1) s (1)) of k(1)(Cl + CH2=CHC(O)CH2CH3) = (2.91 +/-1.10) x 10 (10), k(2)(Cl + CH2=CHOC(O)CH2-CH3) = (2.06 +/- 0.36) x 10 (10) and k(3)(Cl + CH2=CHC(O)OCH2CH3) = (2.53 +/- 0.46) x 10 (10) were obtained using the relative rate method with different references. Structure activity relationships (SARs) were developed for the reactions of Cl with a wide range of unsaturated compounds. On the basis of our kinetic measurements, tropospheric lifetimes of the studied unsaturated compounds are estimated. (C) 2009 Elsevier B. V. All rights reserved.