ASSOCIATIVE REPLICA ORNSTEIN-ZERNIKE EQUATIONS AND THE STRUCTURE OF CHEMICALLY REACTING FLUIDS IN POROUS-MEDIA

A model for a chemically associating fluid, adsorbed in a disordered p orous media, is proposed. The formation of the associates occurs throu gh the directional bonding between the fluid particles. For simplicity , we restrict our attention to the dimerization of particles. In the a bsence of association, this model reduces to that of Kaminsky and Mons on (KM) for the adsorption of methane in a xerosilica gel. This model is studied by means of the replica Ornstein-Zernike ROZ equations, wit h the hypernetted chain approximation, extended for associating fluids . It follows from a comparison with the computer simulation data that this theory yields a very good description of the structural propertie s of the KM model. The influence of the fluid density, the matrix pack ing fraction, and the association energy on the dimerization in the di sordered matrix is studied. The fluid compressibility for the KM model and for the dimerizing fluid in a disordered matrix is obtained via t he compressibility equation. (C) 1997 American Institute of Physics.