Kinetics and mechanisms of OH-induced 2-ethoxyethanol oxidation in the atmosphere

The mechanisms and kinetics for the reaction of 2-ethoxyethanol (2EE) with OH radicals in the presence of O 2 /NO were carried out using ab initio molecular orbital theory based on the QCISD(T)/6-311++G(d,p)//BH&HLYP/6-311++G(d,p) method in conjunction with transition state theory (TST) coupled with Wigner’s tunneling correction at temperatures between 200 and 1000 K. The calculated results indicate that ethylene glycol monoacetate [CH 3 C(O)OCH 2 CH 2 OH], ethylene glycol monoformate [HC(O)OCH 2 CH 2 OH], formaldehyde [HC(O)H], ethyl glycolate [CH 3 CH 2 OC(O)CH 2 OH], and ethyl formate [CH 3 CH 2 OC(O)H] can be the major products for the reaction of 2EE + OH in the presence of O 2 /NO, which are in excellent accord with the experimental observations. The rate constant for the reaction of OH radicals with 2EE at 298 K is computed to be 3.14 × 10 −11 cm 3 molecule −1 s −1 , which is in stronger agreement with the experimental value given by Colmenar et al. (2.17 ± 0.11) × 10 −11 cm 3 molecule −1 s −1 . In the temperature range of 200−1000 K, the calculated TST rate constants for the OH+2EE reaction can be expressed as a function of temperature with k = 1.15 × 10 −14 × ( T /298) 3.9 × exp (2338.2/ T ) cm 3 molecule −1 s −1 .