Theoretical study of hydrogen abstraction from dimethyl ether and methyl tert-butyl ether by hydroxyl radicalElectronic supplementary information (ESI) available: optimized structural parameters, energies, zero point energies and dipole moments for reactants, products, and transition states (Tables S1–8). See http://www.rsc.org/suppdata/cp/b1/b109970c/

Abstract

31G** and CCSD(T)/6-311++G**//MP2/6-31G** calculations have been used to investigate the H-abstraction reaction from CH 3 OCH 3 (DME) whereas MP2/6-31G**//MP2/6-31G** and PMP2/6-31G**//MP2/6-31G** levels have been used to model the H-abstraction reaction from (CH 3 ) 3 COCH 3 (MTBE) by OH. The methodology used has been proved to be adequate to reproduce the experimental geometrical parameters for the reactants and the C-H bond energies. The reaction rate constants for DME, calculated using the transition state theory reproduce the reported experimental results. The fact that H-abstraction is favored from the methoxy group of MTBE in comparison to the tert-butyl group has also been reproduced.y Electronic supplementary information (ESI) available: optimized structural parameters, energies, zero point energies and dipole moments for reactants, products, and transition states (Tables S1-8). See

An ab initio/Rice-Ramsperger-Kassel-Marcus study of the hydrogen-abstraction reactions of methyl ethers, H3COCH3−x(CH3)x, x = 0–2, by ˙OH; mechanism and kinetics

“…For the reaction of DME + OH, they found that the energy barrier for the H-abstraction ''in-plane'' is 2 kcal mol À1 lower than that from ''out-of-plane''. This contrasts with the results of Atadinc et al 10 and Wu et al, 11 who reported that the energy barriers for ''in-plane'' H-abstraction are 2.98 and 2.84 kcal mol À1 higher than that from ''out-of-plane'', respectively.…”

“…Optimized geometries, frequencies, internal rotational potentials, and energies of the stable complexes and saddle points along the intrinsic reaction coordinate (IRC) were calculated on the potential energy surface of reactions of DME, EME and IPME with OH radical. Based on previous studies, [10][11][12] we expected that the potential energy surface would be sensitive to the method used, in which the second-order Møller-Plesset perturbation (MP2) method calculations can locate two transition states for abstraction of the in-plane hydrogen atom of DME and that for out-of-plane hydrogen, while only one transition state (abstraction of out-of-plane hydrogen) can be located using density functional theory (DFT) and the B3LYP functional.…”

“…[3][4][5][6][7][8][9] Most of the experimental results are in good agreement with each other; the most recent high temperature shock tube results obtained by Cook et al 8 are in good agreement with a much earlier estimate by Curran et al 7 Theoretical investigations of DME + OH have been carried out by several groups. [10][11][12][13][14] Wu 11 used the G3//MP2/6-311G(d,p) method to investigate the reaction mechanism and employed variational transition state theory (VTST) with small curvature tunnelling correction to compute rate constants. Their rate constants are 2 times higher than that obtained by Curran et al 7 and Cook et al 8 in the temperature range 800 K to 1500 K.…”

Dual-level direct dynamics studies for the reactions of CH3OCH3 and CF3OCH3 with the OH radical

“…High-temperature values were determined by Curran et al 20 over the temperature range 650-1300 K, and the rate constant at 650 K is close to that of Arif et al 18 Theoretically, an ab initio calculation was carried out to study the CH 3 OCH 3 ϩOH reaction. 21 The rate constants calculated at 298 K using transition state theory with a onedimensional tunneling correction based on an Eckart potential were about 3-7 times lower than the value obtained by Arif et al 18 For reaction ͑R2͒, the rate constants measured by Chen et al ͑268 -308͒ ͑Ref. 22͒ and Hsu et al ͑298 -393 K͒ ͑Ref.…”

Assessment of model chemistries for hydrofluoropolyethers: A DFT/M08‐HX benchmark study

“…By taking these factors into account we opted for an electronic structure method with low CPU time scaling, such as KS‐DFT (which in many cases scales approximately as K 4 , where K is a measure of the size of the molecule, typically related to the number of basis functions). Based on published research concerning the reactivity of a variety of volatile organic compounds and on our own preliminary calculations on HG‐ and ‐ , KS‐DFT (employing M06‐2X and M08‐HX functionals) and MP2 appear to be promising theoretical approaches. In the previously cited list of references M06‐2X is used extensively while M08‐HX is only used once, but because this functional is an improvement on M06‐2X, we opted to make it our benchmark functional in our calculations, which will also include a comparison between the two functionals.…”