Kinetic and product studies of Cl atoms reactions with a series of branched Ketones

摘要

The rate constants for the Cl atom reaction with three branched ketones have been measured at 298 ± 2 K and 760 Torr using the relative rate method in the absence of NO. The rate constants values obtained(in units of 10^(-10)cm^3/(molecule·sec)) are: k_(2-methyl-3-pentanone)=1.07 ± 0.26, k_(3-methyl-2-pentanone)= 1.21 ± 0.26, and k_(4-methyl-2-pentanone)= 1.35 ± 0.27. Combining the chemical kinetic data obtained by this study with those reported for other ketones, a revised Structure Activity Relationship(SAR) parameter and R group reactivity(k_R) of R(O)R′and CHx(x = 1, 2, 3) group reactivity(k_(CHx)) toward Cl atoms were proposed. In addition,the products from the three reactions in the presence of NO were also identified and quantified by using PTR-To F-MS and GC-FID, and the yields of the identified products are: acetone(39% ± 8%) + ethanal(78% ± 12%), 2-butanone(22% ± 2%) + ethanal(75% ± 10%) + propanal(14% ± 1%) and acetone(26% ± 3%) + 2-methylpropanal(24% ± 2%), for Cl atoms reaction with 2-methyl-3-pentanone, 3-methyl-2-pentanone and 4-methyl-2-pentanone, respectively.Based on the obtained results, the reaction mechanisms of Cl atoms with these three ketones are proposed.