Further extractions of metals in carbon dioxide and chelating agents therefor
US5872257A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 1, 1997 |
| Grant date | Feb 16, 1999 |
| Priority date | — |
| Expiry date | Apr 1, 2017 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02P20/54
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
The present invention provides a chelating agent suitable for forming coordinated complexes with a metal in liquid and supercritical carbon dioxide of covalently bonded (i) a chelating group selected from the group consisting of a dithio carbamate, a thiol group, and a picolyl amine group, (ii) a non-electron withdrawing spacer group selected from (CH.sub.2).sub.x ; and (iii) a CO.sub.2 -soluble functional group selected from (CF.sub.2 CF.sub.2 O).sub.X, (CF.sub.2 O).sub.X, (CF.sub.2).sub.X, and CF.sub.2 (CF.sub.3 FO)!.sub.x. X is selected to be greater or equal to 3 and to minimize the electron withdrawing effect of the CO.sub.2 -soluble functional group and to achieve a chelating agent solubility of at least a 10.sup.-3 gm/gm CO.sub.2. A solubility of at least 10.sup.-2 gm/gm CO.sub.2 is attained at a temperature in the range of approximately 0.degree. to 100.degree. C. and a pressure of approximately 500 to 5000 psi.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.