Expired Canadian patentCanada
Nitric acid hydrolysis of polyamides
CA 2225381 C · Owner: Davis, Darwin Darrell · Inventors: Davis, Darwin Darrell; Wilhoit, Eugene Dennis
Overview
Drawings and full text
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Dicarboxylic acid and diamine are recovered from polyamides by hydrolysis with nitric acid, followed by separation of the dicarboxylic acid and , hydrogenation of the nitric acid and then recovery of the diamine.
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 June 13, 1996 and granted September 5, 2000. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended June 13, 2016.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by June 13, 2018.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledJune 13, 1996
GrantedSeptember 5, 2000
Term endedJune 13, 2016
Patent numberCA 2225381 C
Classification (IPC)C07C55/14 +2 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.