ARENEDIAZONIUM SALTS - NEW PROBES OF THE INTERFACIAL COMPOSITIONS OF ASSOCIATION COLLOIDS .2. BINDING CONSTANTS OF BUTANOL AND HEXANOL IN AQUEOUS 3-COMPONENT CETYLTRIMETHYLAMMONIUM BROMIDE MICROEMULSIONS

Yields of aryl ether products, 16-ArOR', were determined by HPLC with excellent reproducibility from dediazoniation of 4-hexadecyl-2,6-dimethylbenzenediazonium tetrafluoroborate (16-ArN2BF4) bound to surfactant aggregates in three-component microemulsions of cetyltrimethylammonium bromide ((CTA)Br), H2O, and an alcohol (R'OH), either 1-butanol (BuOH) or 1-hexanol (HexOH). The results were used to estimate the mole fractions (X(A)) of R'OH bound to the microemulsions, their mole fraction partition constants (K(A)), and mass action binding constants (K(A)'). Values of K(A) decrease with added R'OH consistent with literature results. Unexpectedly, values of K(A)' are constant at all values of X(A), indicating that (CTA)Br mixes ideally with both BuOH and HexOH in aqueous microemulsions and that binding of R'OH to (CTA)Br microemulsions is driven by a hydrophobic effect with minimal contributions from specific interactions between R'OH and (CTA)Br.