Strongly basic macrocyclic triamines, 1,5,9-triazacyclododecanes for solvent extraction of gold(I) cyanide
✍ Scribed by Heung-Jin Choi; Yoon-Kyung Bae; Seok-Chan Kang; Yeon Sil Park; Joon Won Park; Woong-Il Kim; Thomas W Bell
- Publisher
- Elsevier Science
- Year
- 2002
- Tongue
- French
- Weight
- 139 KB
- Volume
- 43
- Category
- Article
- ISSN
- 0040-4039
No coin nor oath required. For personal study only.
✦ Synopsis
Solvent extraction of gold(I) dicyanide anion from alkaline gold(I) cyanide solution using unusually basic amine extractants was conducted. 1,5,9-Triazacyclododecane (4) is known as an unusually basic macrocyclic 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-2,4-dione (1) by N-alkylation with n-dodecyl iodide and then reduction with BH 3 -THF. N,N%-Didodecyl-1,5,9-triazacyclododecane (5) and N,N%,N%%-tridodecyl-1,5,9-triazacyclododecane (6) were efficiently synthesized by selective di-alkylation of 4 with n-dodecyl iodide, and by reductive alkylation of 4 with n-dodecanal, respectively. The extractants 3 and 6 showed pH 50 =10.5, which is the minimum value required for practical application.