Metal ion complexes for use as scale inhibitors
US5057228A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 16, 1990 |
| Grant date | Oct 15, 1991 |
| Priority date | — |
| Expiry date | Apr 16, 2010 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC02F5/14
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
Complex molecules of phosphonic acid ligands and transition metal ions are formed to be surprisingly good at inhibiting and even preventing scale in aqueous solutions, crude oils, aqueous production fluids, heat exchange media, etc. Ethylenediaminetetra(methylenephosphonic) acid (ENTMP) complexed with copper (II) is a particularly effective scale inhibitor over wide pH and temperature ranges. Other useful metal complex molecules include various alkyleneamino(alkylphosphonic) acids, or salts thereof, complexed with transition metals such as nickel (II), cobalt (II) and zinc (II), in addition to copper (II). The active complexes may be termed phosphonate metal complexes, or in some forms, phosphonic acid metal complexes.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.