Expired Canadian patentCanada
Obtaining maleic anhydride not prone to discolor
CA 1291763 C · Owner: Michl, Gerhard · Inventors: Schmidt, Johannes E.; Michl, Gerhard; Seubert, Rolf
Overview
Drawings and full text
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Process for obtaining maleic anhydride that is not prone to discolor by treating crude maleic anhydride with oxygen, a gas mixture containing oxygen, or a substance that releases oxygen before or while it is distilled.
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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 November 5, 1991. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended November 5, 2008.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledDecember 19, 1988
GrantedNovember 5, 1991
Term endedNovember 5, 2008
Patent numberCA 1291763 C
Classification (IPC)C07D307/60 +1 more
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.