Infinite-dilution activity coefficients by the inert gas stripping method:Saturated hydrocarbons in N,N-Dimethylformamide

A simple variant of the inert gas stripping technique employing, as suggest ed by Hradetzky et al. (1988, 1990), gas chromatographic analysis of the li quid phase was applied to measure infinite-dilution activity coefficients ( gamma(infinity)) of ten saturated hydrocarbons in N,N-dimethylformamide at 20 degrees C. For accurate evaluation of gamma(infinity) from inert gas str ipping measurements a second-order approximation formula was derived using the perturbation approach. Here, several effects disregarded in the convent ional first-order approximation (Leroi et al., 1977) are accounted for by e xplicit correction factors. Good performance of this readily applicable exp erimental method is supported by the observed long-term reproducibility of results and their comparison with literature data.