Kinetic and mechanistic aspects of the redox dissociation of tetraphosphorus decasulphide in solution

Abstract

The kinetics of the redox dissociation of P₄S₁₀ dissolved in 1-chloronaphthalene has been studied at 110–150°C. Phosphorus-containing reaction products are P₄S₉ and smaller amounts of phosphorus polysulphides. The reaction is conveniently monitored by means of a simple hydrolysis test. The initial kinetics are quasi-first order, the rate being almost unaffected by dilution. The reaction is insensitive to the presence of oxygen or to the addition of sulphur, but catalysis by iodine and bromine compounds has been observed. A mechanism is proposed which involves, as a first step, the rate-determining fission of P₄S₁₀ into two molecules of metastable P₂S₅.