Isolation of tetrahydrofuran from mixtures which contain tetrahydrofuran, 1,4 butanediol, y-butyrolactone and succinic acid esters
CA 2036627 C · Owner: Fischer, Rolf · Inventors: Harder, Wolfgang; Gosch, Hans-Juergen; Stabel, Uwe
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A process is described for, isolating tetrahydrofuran from mixtures containing tetrahydrofuran, 1,4-butanediol, ~-butyrolactone and succinic acid esters, in which the mixtures are heated to from 150 to 250°C in the presence of phyllosilicates the, resultant tetrahydrofuran and water of reaction are removed from the reaction mixture by distillation and, the tetrahydrofuran is separated from the distillate.
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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
- Filed February 19, 1991 and granted February 13, 2001. 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.