화학공학소재연구정보센터
Journal of the American Chemical Society, Vol.116, No.26, 11779-11786, 1994
Arenediazonium Salts - New Probes of the Interfacial Compositions of Association Colloids .3. Distributions of Butanol, Hexanol, and Water in 4-Component Cationic Microemulsions
Product yields from dediazoniation of 4-hexadecyl-2,6-dimethylbenzenediazonium tetrafluoroborate, 16-ArN2BF4, bound to aggregates of four-component microemulsions composed of cetyltrimethylammonium bromide, (CTA)Br, H2O, hexadecane, and an alcohol, R’OH, either 1-butanol, BuOH, or 1-hexanol, HexOH, were used to estimate changes in H2O and R’OH compositions at the microemulsion interface over a range of microemulsion compositions. Analysis of % 16-ArOR’/% 16-ArOH product percent yield ratios obtained in the water-in-oil microemulsion region of the phase diagram at low water content show that mass action binding constants for the distributions of BuOH and HexOH between the interfacial and oil regions in these microemulsions are independent of [R’OH]. These results indicate that (CTA)Br mixes ideally with both alcohols and that alcohol binding is driven primarily by the hydrophobic effect with minimal contributions from specific interactions between R’OH and (CTA)Br. We also show that our approach provides estimates of molar concentrations of BuOH and H2O in the oil, interfacial, and water regions at any composition of these 4-component microemulsions. Changes in the molar concentrations of H2O and BuOH mark the oil-in-water droplets to bicontinuous to water-in-oil droplets transitions. Potential applications of the dediazoniation method are discussed.