A molecular orbital study of the mechanism of the oxidation of acetylene by peroxyformic acid

Abstract

The restricted Hartree–Fock level of ab initio theory has been used to study the reaction of peroxyformic acid with acetylene. Various plausible directions of the peroxy-acid approach to acetylene, believed to lead to molecular arrangements of both components which are near the transition state for the formation of oxiren, were investigated. The unsymmetrical attack of the peroxy-acid on acetylene is energetically more favourable than the symmetrical one. The peroxy-acid approach appears to be dominated by charge-transfer interactions. Theoretical investigation of the second-step of reaction, i.e. the oxidation of oxiren to 2,4-dioxabicyclo[1.1.0]butane, shows that such a molecule cannot exist. Nevertheless, the possibility of a diradical state for this species cannot be ruled out.