Process for producing pyrrolidone and n-alkyl pyrrolidones
CA 2129649 C · Owner: Akzo Nobel Nv · Inventors: Bergfeld, Manfred; Wiesgickl, Gunter
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The invention relates to a process for producing pyrrolidone and N-alkyl pyrrolidones from saturated or unsaturated 1,4-dicarboxylic acids or their anhydrides; hydrogen; and a primary amine or ammonia characterized in that, the dicarboxylic acid or its anhydride is allowed to react in an appropriate reactor with hydrogen via a first catalyst bed and the unisolated intermediate product is subsequently reacted with the primary amine or ammonia directly via a second, downstream catalyst bed.
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 February 3, 1993 and granted September 23, 1997. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended February 3, 2013.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by February 3, 2015.
- 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.