Cl atoms-initiated degradation of 1-Chlorobutane and 2-Chlorobutane: Kinetics, product analysis and atmospheric implications

Abstract

The relative rate method was employed to investigate the kinetics of the Cl-initiated reactions of 1-chlorobutane (1-CB) and 2-chlorobutane (2-CB) over 263–363 K, and the measured rate coefficients at room temperature are (1.04 ± 0.24) × 10−10 and (5.84 ± 0.27) × 10−11 cm3 molecule−1 s−1, respectively. The Arrhenius equations for the title reactions were derived to be k1-CB + Cl (T = 263–363 K) = (2.77 ± 0.72) × 10−11 exp [(422 ± 79)/T] and k2-CB + Cl (T = 263–363 K) = (1.40 ± 0.32) × 10−11 exp [(415 ± 70)/T] cm3 molecule−1 s−1, respectively. The products were analysed qualitatively using gas chromatography-mass spectrometry (GC-MS), and the reaction mechanism was proposed for the reactions. The rate coefficients for the title reactions were calculated computationally over the temperature range of 200–400 K using canonical variational transition state theory with appropriate tunnelling corrections at CCSD(T)/6–311++G(2d,2p)//BHandHLYP/6–311++G(2d,2p) level of theory to complement our experimentally measured kinetic parameters. The experimental and theoretical data obtained were used to evaluate the impact of the studied molecules in the troposphere.