Preparation of tetrahydrofuran and .gamma.-butyrolactone
CA 2036626 C · Owner: Zimmermann, Horst · Inventors: Brenner, Karl; Scheiper, Hans-Juergen; Zimmermann, Horst
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A process for the preparation of tetrahydrofuran or tetrahydrofuran and .gamma.-butyrolactone from the product of the hydrogenation of malefic acid, succinic acid malefic, anhydride, succinic anhydride and/or fumaric acid by, treating the crude hydrogenation product without prior, work-up, at from 100 to 300°C with a protic acid and, isolating pure tetrahydrofuran and .gamma.-butyrolactone from the resultant reaction mixture by distillation.
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 19, 1991 and granted November 7, 2000. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended February 19, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by February 19, 2013.
- 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.