Purification of phosphoric acid
CA 1055419 A · Owner: Hoechst Aktiengesellschaft · Inventors: Ehlers, Klaus-Peter; Scheibitz, Wolfgang; Wojtech, Bernhard
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Phosphoric acid is purified. To this end it is, dissolved in an organic solvent completely miscible with water. More particularly, the phosphoric acid is mixed with a solvent having a boiling point higher than that of water or higher than that of the resulting azeotrope; the resulting solution is heated to temperatures between the boiling point of water or the azeotrope and that of the solvent for as long a period as necessary to distillatively free the solution from the bulk of uncombined water therein; and the phosphoric acid solution is separated from residue.
Read the whole patent
Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Granted May 29, 1979. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended May 29, 1996.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.