Photochemistry of 2,2-dichloroethanol: kinetics and mechanism of the reaction with Cl atoms and OH radicals

Abstract

Smog chamber/FTIR techniques were used to investigate the kinetics and mechanism of the Cl atom and OH radical initiated oxidation of 2,2-dichloroethanol at (296 ± 1) K. Relative rate methods were used to measure k(Cl + CHCl₂CH₂OH) = (5.87 ± 0.96) × 10⁻¹² and k(OH + CHCl₂CH₂OH) = (5.54 ± 1.94) × 10⁻¹³ cm³ molecule⁻¹ s⁻¹. Chlorine atom initiated oxidation of CHCl₂CH₂OH in one atmosphere of air gives HCOCl, CHCl₂CHO, and COCl₂ in yields of (62 ± 5)%, (39 ± 10)%, and (8 ± 2)%, respectively. The rate constant k(Cl + CHCl₂CHO) = (8.3 ± 16) × 10⁻¹² cm³ molecule⁻¹ s⁻¹ was determined and the IR spectra of CHCl₂CHO is reported for the first time. The atmospheric lifetime for CHCl₂CH₂OH is estimated as 21 days. The experimental results are discussed in the context of the atmospheric chemistry of chlorinated alcohols.