Process for the preparation of 2-nitro-5-fluoro- or -5-chlorophenol
CA 2080208 A1 · Owner: Papenfuhs, Theodor · Inventors: Forstinger, Klaus; Pfirmann, Ralf; Papenfuhs, Theodor
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Abstract of the Disclosure: Process for the preparation of 2-nitro-5-fluoro- or -5chlorophenol, The present invention relates to a process for the preparation of isomerically pure 2-nitro-5-fluoro- or -5chlorophenol, by reacting 2,4-difluoronitrobenzene or 2,4-dichloronitrobenzene with aqueous alkali metal or alkaline earth metal hydroxide solution or suspension in the absence of organic solvents or other solubility promoting substances at temperatures from about 20°C to about 190°C, adjusting the pH of the reaction mixture to about 1 to about 6 by the addition of acid steam, distilling the resultant product and isolating it from the distillate after cooling.
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 October 8, 1992. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended October 8, 2012.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by October 8, 2014.
- 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.