City Research Online

Abstract

An introduction to photochemistry with a review on organophosphorus photochemistry is given in chapters one and two respectively.

In chapter three the chemistry of singlet oxygen and its reaction with anthracenyl compounds is discussed. The photooxidation of a variety of anthracenyl phosphorus compounds has been studied, and found to occur via a Type II process. All products observed can be accounted for by involving a 9,10-endoperoxide which may subsequently fragment, resulting in cleavage of the phosphorus moiety from the anthracene nucleus. The participation of singlet oxygen has been shown by solvent isotope studies, and by the isolation and subsequent thermolysis of a 9,10-endoperoxide. Where fragmentation of an endoperoxide occurs, the phosphorus moiety may be lost as a phosphorus ylid. The influence of phosphorus on anthracenyl photooxidation chemistry and the synthetic potential of this work is mentioned.

The principal methods for oxidative desulphurisation at pentavalent phosphorus are reviewed in chapter four. The photochemistry of 1,2-dicarbonyl based compounds is discussed in the light of their ability to epoxidize olefins. It has been found that the oxidation of phosphorus thionate and thiolate compounds may be achieved by the photochemical generation of peroxy radicals from 1,2-dicarbonyl compounds. The reaction of such peroxy radicals with a number of thiophosphoryl compounds is shown to result in the formation of the phosphoryl analogue, while thiolate compounds are transformed into their corresponding phosphorus acid. The significance of this work towards the activation and detoxication of thiophosphorus pesticides is mentioned, and illustrated by the oxidative desulphurisation of parathion and chlormephos. Finally a number of novel chemical methods which may carry out a similar thiophosphoryl phosphoryl interconversion are given.

Publication Type:	Thesis (Doctoral)
Subjects:	Q Science > QD Chemistry T Technology > TP Chemical technology
Departments:	School of Science & Technology > School of Science & Technology Doctoral Theses Doctoral Theses

Export

Downloads