Solvent extraction studies. Part VII. The ammonia–tri-n-butyl phosphate system

Abstract

The solubility of ammonia in tri-n-butyl phosphate has been measured over the temperature range –65—+20 °C. For tributyl phosphate–liquid ammonia, the solubility increases with increasing temperature, with a maximum NH₃:Bu₃PO₄ ratio of 3·64 at –35 °C. N.m.r. studies show that hydrogen-bonding between NH₃ and Bu₃PO₄ is weaker than in the Bu₃PO₄–H₂O system. With gaseous ammonia, the temperature-dependence of the solubility leads to ΔH_sol=–2·54 kcal mol^–1. The results are compared with those for the Bu₃PO₄–H₂O system.