A comparative study of the catalytic action of water-miscible organic solvents on the hydrolytic degradation of long-chain polyphosphates

Abstract The hydrolytic degradation of sodium polyphosphate (Na PP ) catalysed by six water-miscible organic solvents—methanol, ethanol, n -propanol, t -butanol, acetone and dioxane—was studied. This was done principally to compare their catalytic actions and to have a fresh look at the factors responsible for it. The values of energy of activation ( E ) obtained using 40% (v/v) of the solvents ranged from 12.1 to 15.3 kcal mol −1 . Taking into account the values of dielectric constant (ϵ) of the solvent media at all temperatures at which the rate of degradation was studied, it was found that the lower the average value of ϵ, the lower was the value of E . The product of ϵ and the dipole moment, referred to as the electrostatic factor (EF), of the pure solvents also appeared to have a profound influence on the course of degradation. Dioxane, with a zero value of EF, was the most effective solvent in catalysing the hydrolytic degradation of Na PP .