An experimental and theoretical study of photo-oxidation reaction of 2-methyl tetrahydrofuran with Cl atom under atmospheric conditions.

Temperature-dependent rate coefficients for the reactions of 2-methyl tetrahydrofuran (MTHF) with Cl atoms in the temperature range of 268-343 K at atmospheric pressure were measured using the relative-rate method. Ethylene and propane were used as reference compounds. Quantitative analysis of the post-photolysis reaction mixture was conducted using a gas chromatograph paired with a flame ionization detector (GC-FID). A gas chromatograph connected to a mass spectrometer (GC-MS) was employed for the purpose of qualitative analysis. In the experimental temperature range, the derived Arrhenius expression for the title reaction is represented by the equation k M T H F + C l Expt 268 - 343 K = ( 1.48 ± 0.13 ) × 10 - 12 × e x p 1474.51 ± 25.16 T cm 3 molecule -1  s -1 . In addition to our experimental findings, we conducted computational calculations employing the CCSD(T)//BHandHLYP/6-31 + G(d,p) level of theory to complement our study. The canonical transition state theory (CTST) was utilized to compute the rate coefficients at 250-400 K and 760 Torr. The Arrhenius expression for the theoretically calculated "k" values is found to be k M T H F + C l Theory 250 - 400 K = ( 1.51 ± 0.10 ) × 10 - 12 × e x p 1544.97 ± 22.14 T cm 3 molecule -1  s -1 . The local reactivity parameters, such as Fukui functions ( f r 0 ), local softness ( s r 0 ), and global softness ( S ) were also calculated theoretically to understand the site-specific reactivity trend of MTHF towards Cl atoms. The atmospheric implications, branching ratios, degradation mechanism, and feasibility of the reaction are discussed in this study.