The behaviour of some organophosphorus(V) compounds in strongly acidic solvents. Part 1. Monophenyl derivatives

Abstract

The reactions of PPhO(OH)₂ and PPhCl₂O with the strongly acidic solvents 100% H₂SO₄, 25 and 65 oleum, and HSClO₃ have been investigated by means of ³¹P n.m.r. spectroscopy. Initial protonation of the phosphoryl oxygen, the extent of which varies with solute and solvent, is followed in most instances by sulphonation of the aromatic group (except in H₂SO₄), and/or condensation [PPhO(OH)₂] or solvolysis (PPhCl₂O). Slow chlorination of PPhO(OH)₂ was also observed in HSClO₃. Attempts to prepare the intermediate compound PPhClO(OH) did not yield pure products, but reaction of two of the mixtures thus obtained with 100% H₂SO₄ and HSClO₃ confirmed its participation in some of the above systems.