Strongly basic macrocyclic triamines,1,5,9-triazacyclododecanes for solvent extraction of gold(I) cyanide

摘要

Solvent extraction of gold(I) dicyanide anion from alkaline gold(I) cyanide solution using unusaully basic amine extractants was conducted.1,5,9-Triazacyclododecane (4) is known as an unusually basic macrocclic amine having pK_a=12.3-12.7,and is thus a good candidate as a basic amine extractant.Three lipophilic derivatives of 4 expected to stay in the organic phase during gold solvent extraction were synthesized.N-Dodecyl-1,5,9-triazacyclododecane (3) was prepared from 1,5,9-triazacyclododecane (5) and N,N',N"-tridodecyl-1,5,9-triazacyclododecane (6) wee efficiently synthesized by selective di-alkylation of 4 with n-dodecyl iodide,and by reductive alkylation of 4 with n-dodecanal,respectivley.The extractants 3 and 6 showed pH_(50)=10.5,which is the minimum value required for practical application.