Theoretical model for electrophilic oxygen atom insertion into hydrocarbons

Journal Article · Wed Jun 30 00:00:00 EDT 1993 · Journal of the American Chemical Society; (United States)

DOI:https://doi.org/10.1021/ja00066a049· OSTI ID:5748006

Bach, R D; Su, M D ^[1]; Andres, J L ^[2]; McDouall, J J.W. ^[3]

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1. Wayne State Univ., Detroit, MI (United States)
2. Universitat Autonoma de Barcelona (Spain) Wayne State Univ., Detroit, MI (United States)
3. Univ. of Manchester (United Kingdom)

A theoretical model suggesting the mechanistic pathway for the oxidation of saturated-alkanes to their corresponding alcohols and ketones is described. Water oxide (H[sub 2]O-O) is employed as a model singlet oxygen atom donor. Molecular orbital calculations with the 6-31G basis set at the MP2, QCISD, QCISD(T), CASSCF, and MRCI levels of theory suggest that oxygen insertion by water oxide occurs by the interaction of an electrophilic oxygen atom with a doubly occupied hydrocarbon fragment orbital. The electrophilic oxygen approaches the hydrocarbon along the axis of the atomic carbon p orbital comprising a [pi]-[sub CH(2)] or [pi]-[sub CHCH(3)] fragment orbital to form a carbon-oxygen [sigma] bond. A concerted hydrogen migration to an adjacent oxygen lone pair of electrons affords the alcohol insertion product in a stereoselective fashion with predictable stereochemistry. Subsequent oxidation of the alcohol to a ketone (or aldehyde) occurs in a similar fashion and has a lower activation barrier. The calculated (MP4/6-31G*//MP2/6-31G*) activation barriers for oxygen atom insertion into the C-H bonds of methane, ethane, propane, butane, isobutane, and methanol are 10.7, 8.2, 3.9, 4.8, 4.5, and 3.3 kcal/mol, respectively. We use ab initio molecular orbital calculations in support of a frontier MO theory that provides a unique rationale for both the stereospecificity and the stereoselectivity of insertion of electrophilic oxygen and related electrophiles into the carbon-hydrogen bond. 13 refs., 7 figs., 2 tabs.

• OSTI ID: 5748006
• Journal Information: Journal of the American Chemical Society; (United States), Vol. 115:13; ISSN 0002-7863
• Country of Publication: United States
• Language: English

Related Subjects

10 SYNTHETIC FUELS
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ALKANES
OXIDATION
ALCOHOLS
ALDEHYDES
BUTANE
ETHANE
KETONES
METHANE
METHANOL
MOLECULAR ORBITAL METHOD
OXYGEN
PROPANE
THEORETICAL DATA
WATER
CALCULATION METHODS
CHEMICAL REACTIONS
DATA
ELEMENTS
HYDROCARBONS
HYDROGEN COMPOUNDS
HYDROXY COMPOUNDS
INFORMATION
NONMETALS
NUMERICAL DATA
ORGANIC COMPOUNDS
OXYGEN COMPOUNDS
100200* - Synthetic Fuels- Production- (1990-)
400201 - Chemical & Physicochemical Properties