Dynamical critical phenomena in chemically reactive fluid mixtures

Abstract

It is shown that the interplay between chemical reactions and thermodynamic stability gives rise to some novel phenomena manifested in a slowing down of the chemical reaction and in changes in the critical behavior of transport processes. In an $n$-component fluid, when all the components participate in the reaction, the rate vanishes near the critical point ${T}_{c}$ as ${[\frac{(T\ensuremath{-}{T}_{c})}{{T}_{c}}]}^{\ensuremath{\gamma}}$, where $\ensuremath{\gamma}\ensuremath{\sim}1.25$. When one of the components does not participate in the reaction, the rate vanishes, in general, as ${[\frac{(T\ensuremath{-}{T}_{c})}{{T}_{c}}]}^{a}$, where $a\ensuremath{\sim}0.12$. If more than one component is nonreactive the rate of the reaction is not sensitive to the approach to ${T}_{c}$. Reactive binary mixtures are treated in detail on the basis of a mode-coupling theory. In contrast to nonreactive mixtures, the shear viscosity has no divergence near the critical point. In addition, the diffusion coefficient has a different temperature and wave-vector dependence.