Kinetics and mechanism of 3-chloro-2-methyl-1-propene(3-ClMP) initiated by OH radical: an insight from DFT calculations^[1]

In this manuscript, OH-initiated gas phase reactions of 3-chloro-2-methyl-1-propene [CH2=C(CH3)CH2Cl] has been carried out by using density functional theory (DFT) method. We have chosen M06-2X hybrid density functional method along with 6-31 + G(d,p) basis set for optimisation and vibrational frequency calculations of all the relevant molecular species of the titled reaction. Energetic calculations have been further refined at CCSD(T) method along with cc-pVTZ basis set in order to obtain higher degree of precision of thermo-chemical and kinetic results. Energy profile is presented for all stationary points involved in the titled reaction and thermochemistry for all possible reaction channels (H-abstraction and OH-addition reactions) has been analysed. Canonical Transition State Theory (CTST) has been employed to determine the rate constants within the temperature range of 250–450 K and Our reported rate constant at 298 K are found to be close to the reported experimental rate constant. The atmospheric lifetime of the titled molecule has also been reported in this work. We have also reported standard enthalpies of formation of the titled molecule and generated product radicals by using group-balanced isodesmic reaction schemes.