Theoretical determination of molecular structure and conformation. 18. On the formation of epoxides during the ozonolysis of alkenes
The reaction of carbonyl oxide (CH/sub 2/OO) and ethylene has been investigated by ab initio techniques. According to theoretical results, carbonyl oxide can act as an oxygen-transfer agent, thus leading to epoxide and aldehyde: C/sub 2/H/sub 4/ + CH/sub 2/OO ..-->.. CH/sub 2/OCH/sub 2/ + CH/sub 2/O. The calculated transition-state energies of the various epoxidation modes are 4-8 kcal/mol, which are comparable to activation energies of cycloaddition (cycloreversion) reactions encountered in the ozonolysis of alkenes. Epoxidation of alkene by carbonyl oxide is best described as a S/sub N/2 reaction on the terminal oxygen atom of carbonyl oxide. The preferred collision mode of the O-transfer reaction can be rationalized on the basis of frontier orbital interactions. Apart from epoxidation, carbonyl oxide can add to ethylene, yielding 1,2-dioxolane. The energy requirements of the cycloaddition are equivalent to those of the epoxidation. However, 1,2-dioxolanes will only be observed under normal ozonolysis conditions if the excess energy generated in the cycloaddition reaction is readily dissipated. Otherwise, 1,2-dioxolanes will immediately decompose, again yielding, among other products, epoxides.
- Research Organization:
- Universitaet Koeln, West Germany
- OSTI ID:
- 5532873
- Journal Information:
- J. Am. Chem. Soc.; (United States), Vol. 108:12
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ALDEHYDES
CHEMICAL PREPARATION
MOLECULAR STRUCTURE
CARBONYLS
CHEMICAL REACTIONS
EPOXIDES
ETHYLENE
OXIDES
ACTIVATION ENERGY
CALCULATION METHODS
FORMATION HEAT
OXYGEN
THEORETICAL DATA
THERMODYNAMICS
ALKENES
CHALCOGENIDES
DATA
ELEMENTS
ENERGY
ENTHALPY
HYDROCARBONS
INFORMATION
NONMETALS
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
REACTION HEAT
SYNTHESIS
THERMODYNAMIC PROPERTIES
400301* - Organic Chemistry- Chemical & Physicochemical Properties- (-1987)