An Ab Initio RRKM-Based Master Equation Study for Kinetics of OH-Initiated Oxidation of 2-Methyltetrahydrofuran and Its Implications in Kinetic Modeling

Cyclic ethers (CEs) can be promising future biofuel candidates. Most CEs possess physico-chemical and combustion indicators comparable to conventional fuels, making them suitable for internal engines. This work computationally investigates the kinetic behaviors of hydrogen abstraction from 2-methyl tetrahydrofuran (2MTHF), one CEs, by hydroxyl radicals under atmospheric relevant conditions. The various reaction pathways were explored using CCSD(T)/cc-pVTZ//M06-2X/aug-cc-pVTZ level theory. Rice–Ramsperger–Kassel–Marcus-based master equation (RRKM-ME) rate model, including treatments hindered rotation tunneling, was employed describe time-dependent species profiles pressure temperature-dependent coefficients. Our model revealed that H-abstraction proceeds via an addition-elimination mechanism forming complexes at both entrance exit channels. Eight different channels yielding five radical products located. exhibited complex kinetics a U-shaped Arrhenius behavior. An unusual occurrence negative temperature dependence observed low temperatures, owing barrier height C-H bond vicinity O-atom. A shift in with dominance Cα-H 2MTHF ring (causing negative-T dependence) CH3 (positive-T high respectively. Interestingly, effect revealing significance pre-reaction complex. Under pressure, our theoretical coefficients showed excellent agreement available literature data. nicely captured temperatures. predicted global expressed as k (T, 760 Torr) = 3.55 × 101 T−4.72 exp [−340.0 K/T] + 8.21 10−23 T3.49 [918.8 (cm3/molecule/s). provides detailed picture OH-initiated oxidation 2MTHF. Hence, this information is useful building me chanism methylated cyclic ethers.