Complex Formation in Tertiary Amine Extraction of Trivalent Metals
Toluene solutions of trilaurylammoniumchloride in equilibrium with dilute hydrochloric acid contain an amount of water which corresponds to amine salt monohydrate. In contact with hydrochloric acid of increasing concentration, the organic phase extracts increasing amounts of excess acid, whereas the water content decreases. From distribution studies with acidic concentrated chloride solutions, it can be concluded that the extraction of excess acid is due mainly to amine dihydrochloride formation. The water content is independent of excess acid present in the organic phase, and is proportional to the water activity. Physicochemical investigations of the organic phases (infrared absorption, conductivity, cryoscopic measurements) confirm the interpretation of analytical data as to amine dihydrochloride formation and to amine salt hydration.