Reactions of dimethyl ether with atomic oxygen: A matrix isolation and a quantum chemical study
Journal Article
·
· Journal of Physical Chemistry A: Molecules, Spectroscopy, Kinetics, Environment, amp General Theory
- Ruhr-Univ., Bochum (Germany). Lehrstuhl fuer Organische Chemie II
- Univ. of Goeteborg (Sweden)
The reaction of dimethyl ether (1) with atomic oxygen generated by photolysis of ozone or N{sub 2}O was examined in low-temperature matrices. The major reaction products are two conformers of methoxymethanol (5). IR absorptions of the products were assigned by isotopic labeling ({sup 18}O and D) and DFT calculations at the B3LYP/6-311++G(d,p) level of theory. The mechanism of the formation of 5, in particular H abstraction from 1 by atomic oxygen (O{sup 3}P and O{sup 1}D), was investigated using UMP, UCCSD(T), and UDFT. In both the H abstraction and the O({sup 1}D) insertion reaction, the out-of-plane C-H bonds of 1 are preferentially attacked since the in-plane C-H bonds are about 10 kcal/mol stronger. In the case of a reaction with O({sup 3}P), an Arrhenius activation energy of 3.5 kcal/mol is calculated at 298 K, which compares well with an experimental value of 2.85 kcal/mol. In the exit channel of the reaction, a radical-radical complex between CH{sub 3}CH{sub 2}{center_dot} and {center_dot}OH ({minus}2.7 kcal/mol relative to separated products) is found. The latter is the starting point for the formation of 5 and helps to rationalize the stereoselectivity of the reaction leading to particular conformations of 5.
- OSTI ID:
- 352680
- Journal Information:
- Journal of Physical Chemistry A: Molecules, Spectroscopy, Kinetics, Environment, amp General Theory, Journal Name: Journal of Physical Chemistry A: Molecules, Spectroscopy, Kinetics, Environment, amp General Theory Journal Issue: 19 Vol. 103; ISSN 1089-5639; ISSN JPCAFH
- Country of Publication:
- United States
- Language:
- English
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