11th International Symposium on Surfactants in Solutions Abstracts, Jerusalem, Israel, p. 270 (1996)
ABSTRACT. From the flocculation tests of the systems, containing dispersed particles with azacrown ethers (mono- and poly-) we found that macrocycle - triazadibenz-18-crown-6 (ACE) - hemisorb on the surface of noble metals, providing the selectivity of adsorption and flocculation under certain conditions. We suggested to use emulsions with such structures dissolved in the organic phase, for the selective adagulation of fine gold particles on the oil droplets, with following extraction of dispersed phase into the oil. Trithiodiazadibenzo-15-crown-5 (TCE) and monobenzo-15-crown-5 (OCE) were tested to compare the selectivity of the modifying action of macrocycles with different heteroatoms. Adagulation tests were combined with the preferential wetting measurements. For ACE solutions essential increase of the contact angle and wetting inversion is observed. The strong hydrophobic effect of ACE solutions on the gold surfaces correlates with high extraction ability and the selectivity of ACE towards gold particles in the flocculation and adagulation tests. This effect is provided by optimal combination of specific coordination bonding with gold surface, special conformation and orientation of the molecule in the absorbed layer, and strong hydrophobic action of the benzene rings of the macrocycle structure.