Kinetics and mechanism of phosphite oxidation by iodine(7), catalyzed by tungsten(6)

Kinetics and mechanism of tungsten(6)-catalyzed phosphine oxidation with iodine(7) have been investigated. It has been found that tungsten exhibits its catalytic activity only when Csub(H3O+(>=)9x10-4 molx1-1. Reaction rate passes the maximum as the concentration of tungsten(6) increases. The reduction of reaction rate at Csub(W(6))> 1x10-5 gxmol/l is due to the formation of polymeric forms of tungsten(6) which do not exhibit any catalytic activity. The protonated form of tungsten(Wsub(O3OH-)) has been found to have the highest catalytic power