Theoretical study of hydrogen abstraction from dimethyl ether and methyl tert-butyl ether by hydroxyl radical

Abstract

MP2/6-31G**//MP2/6-31G**, PMP2/6-31G**//MP2/6-31G**, MP4/6-311G(3df,2p)//MP2/6-31G**, PMP4/6-311G(3df,2p)//MP2/6-31G** and CCSD(T)/6-311++G**//MP2/6-31G** calculations have been used to investigate the H-abstraction reaction from CH₃OCH₃ (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 (CH₃)₃COCH₃ (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.