TERNARY DIFFUSION IN THE SYSTEM N-PROPANOL PLUS 1-CHLOROBUTANE PLUS N-HEPTANE AT 25-DEGREES-C

We report on measurements of mutual diffusion in the ternary system n- propanol (1) + 1-chlorobutane (2) + n-heptane (3) at 25-degrees-C meas ured by the diaphragm cell technique. The data cover equimolar concent rations, c1 = c2, from dilute solutions (c1 = c2 much-less-than c3) up to the binary system (c3 = 0), including the case c1 = c2 = c3. In co njunction with molar volume data, measured in this work, and activity coefficient data taken from the literature, they enable the calculatio n of the phenomenological coefficient L(ij) of the thermodynamics of i rreversible processes. These coefficients are reported for coordinate systems fixed relative to the local center-of-volume, local center-of- mass, and relative to one component (n-heptane) being at rest. The phe nomenological coefficients are used to examine the validity of Onsager 's reciprocity relation (ORR). The ORR is fulfilled in all cases. Meth ods for non-linear parameter estimation as applied to diaphragm cell d iffusion studies are discussed.