Process for manufacture of lithium hexafluorophosphate
US5935541A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 3, 1998 |
| Grant date | Aug 10, 1999 |
| Priority date | — |
| Expiry date | Jun 3, 2018 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC01D15/005
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
The process of the present invention consists in bringing into contact, on the one hand, (A) gaseous phosphorus pentafluoride or a gaseous mixture comprising phosphorus pentafluoride and hydrochloric acid, and, on the other hand, (B) a solution of lithium fluoride in hydrofluoric acid, in a column (10) having a sufficient number of transfer units to carry out the reaction of PF.sub.5 with LiF under the chosen conditions of temperature, of pressure and of molar ratio of the two contrasting reactants and with complete or substantially complete absorption of the PF.sub.5 in the column. This process makes it possible to solve the problems of blockage by preventing recrystallizations of salts; to discharge the heat given off by the reaction by the evaporation of a portion of the HF; and to separate the HCl which may be contained in the starting PF.sub.5, without loss of PF.sub.5, thus allowing subsequent recovery/value enhancement of this HCl. Moreover, this process is very simple, with a very small number of stages, which makes it possible to avoid any entry of air or moisture capable of contaminating the final LiPF.sub.6.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.