Behaviour of some organophosphorus(V) compounds in strongly acidic solvents. Part 2. Ph2P(O)OH, Ph2P(O)Cl, Ph3PO, Ph3PS, and MeP(O)-Cl2

Abstract

The reaction of Ph₂P(O)OH, Ph₂P(O)Cl, Ph₃PO, Ph₃PS, and MeP(O)Cl₂, with the strongly acidic solvents 100% H₂SO₄, HSClO₃, 25 and (in most cases) 65 oleum have been investigated by ³¹P n.m.r. spectroscopy. The initial reaction is protonation of the phosphoryl oxygen for phosphoryl compounds, although Ph₃PS appears not to protonate. Further reactions including sulphonation of the aromatic rings, and/or solvolysis of phosphorus–chlorine bonds, have also been observed in many instances. The relative basicities of these and other phosphorus(V) compounds are discussed on the basis of the results.