Quantum Mechanical Approach to Gas Phase Reaction of Isopropanol with Sulfanyl Radical ☆

i-C3H7OH (IPA) is one of the potential fuel additives. The reaction mechanism of isopropanol with sulfanyl radical was investigated at the CCSD(T)//B3LYP/6-311+G(3df,2p) level of theory. Ten possible reaction pathways giving PR1-PR10 including three H-abstraction reactions and seven substitution reactions were considered. Based on the determined potential energy surface and molecular parameters, the rate constants and branching ratios of each reaction pathway were calculated at the temperature range of 298K - 2000K by using the transition state theory considering the Eckart tunnel effect. The kinetics results showed that at 298 K, the reaction products were mainly PR2 ((CH3)2COH + H2S) (~ 100%). However, at 2000 K, the contribution of PR2 decreased to 77.8% of the total product, while, PR3 (CH3CH(CH2)OH + H2S) and PR1 ((CH3)2CHO + H2S) accounted for 16.7% and 5.5% of the total product, respectively.