No abstract

Ion-solvent interactions have been studied in cyclohexane solutions of sodium tetra-ro-butylaluminate (NaAl-Bu4) as a function of added tetrahydrofuran (THF) using differential vapor pressure analysis. Departure from ideality, as determined by means of the differential vapor pressure method, is attributed to an aggregation process. The apparent degree of aggregation varies from ion pairs at a concentration of approximately 0.0025 M to an aggregation number of 6 at a concentration of the order of 2 M. Addition of THF to the salt solutions is found to lower the apparent molecular weight of the solute relative to that of the corresponding solvated aggregate. The magnitude of this effect is found to increase with both an increase in the ratio of THF: NaAlBui and with an increase in NaAlBu4 concentration. This is attributed to a loss of aggregate stability in both instances.