A Theoretical Study of the Epoxidation of Olefins by Peracids.
For the parent reacting system, HCOOOH + CH(2)=CH(2) --> HCOOH + ethylene oxide, the overall potential energy surface has been determined using ab initio methods. The oxygen-addition transition state is found to be remarkably similar to that deduced experimentally. The O-H bond is retained in the transition state. Reasonable kinetic isotopic effects are obtained theoretically. The transition state leads to an unprecedented transient intermediate. That intermediate is converted to a hydrogen-bonded system between ethylene oxide and formic acid. Substituent effects on transition-state geometries are small, but the effects on activation energies are large.
Yamabe
Shinichi
S
Department of Chemistry, Nara University of Education, Takabatake-cho, Nara 630, Japan, and Institute for Natural Science, Nara University, 1500 Misasagi-cho, Nara 631, Japan.
Kondou
Chisako
C
Minato
Tsutomu
T