Preparation of 3,4,6-trifluorophthalic acid
CA 2079464 A1 · Owner: Occidental Chemical Corporation · Inventors: O'Reilly, Neil J.; Lin, Henry C.; Derwin, William S.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
2079464 9116308 PCTABS00007, 3,4,6-trifluorophthalic acid is prepared in high yield by reaction of a 3,4,6-trichloro-N-substituted phthalimide with potassium fluoride at temperatures in the range of 200· to 270 ·C in the absence of a catalyst to form the corresponding trifluoro-N-substituted phthalimide which in turn, is hydrolyzed to form the, 3,4,6-trifluorophthalic acid.
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
- Filed April 2, 1991. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended April 2, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by April 2, 2013.
- 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.