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Expired Canadian patentCanada

Process for the preparation of n-acetyl-p-aminophenol

CA 1297129 C · Owner: Sathe, Sharad Somnath · Inventors: Sathe, Sharad Somnath

CIPO record

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Abstract From the Canadian patent

Abstract of the Disclosure, An improved process for the preparation of N-acetylp-aminophenol. p-Aminophenol is acetylated in an aqueous medium to produce a crude aqueous reaction mixture and N-acetyl-p-aminophenol product is recovered by crystallization from an aqueous system comprising the reaction mixture. Crystals are separated from the crude mother liquor which contains residual N-acetyl-p-aminophenol and unreacted acetic acid. According to the improvement residual N-acetyl-paminophenol and acetic acid are recovered from the crude mother liquor by liquid-liquid extraction with a water-immiscible organic solvent to produce an extract containing N-acetyl-p-aminophenol and acetic acid. The …

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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 March 10, 1992. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended March 10, 2009.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledNovember 7, 1985
GrantedMarch 10, 1992
Term endedMarch 10, 2009
Patent numberCA 1297129 C
Classification (IPC)C07C231/02 +1 more

Timeline

Timeline From CIPO dates

19861989199219951998200120042007Application filedNov 7, 1985Patent grantedMarch 10, 1992Term endedMarch 10, 2009

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Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.