Effect of stability of nanosized catalyst-polymer substrate complex on hydrolysis of poly(<Emphasis Type="Italic">N</Emphasis>-vinylpyrrolidone) in copper sols

The causes of a high total conversion and the S-shaped pattern of the time dependence of conversion for copper sol-catalyzed hydrolysis of the lactam rings of poly(N-vinylpyrrolidone) have been studied. The high conversion of the hydrolusis is achieved via replacement of modified macromolecules in shields of catalyst particles with less modified macromolecules from the dispersion medium of a sol in the course of reaction owing to a decline in the stability of copper nanoparticle complexes with macromolecules with an increase in the degree of hydrolysis. A reduction in the complex stability leads to an increase in the lability of bonding of shielding polymer chains with the catalyst surface and to the growth of the rate of rearrangement and the overall rate of reaction after the induction period. This situation is also responsible for the enlargement of nanosized catalyst particles in the course of reaction and the destruction of the sol after a limiting conversion of units of ～40–50% is attained.