Process for reducing the free aldehyde content in n-alkylol amide monomers
CA 2116318 C · Owner: Celanese International Corporation · Inventors: Leighton, John C.; Chandran, Rama S.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
In a process for the preparation of N-alkylol amide monomers wherein a polymerizable amide is reacted with an aldehyde the improvement which comprises adjusting the pH of the resulting N-alkylol amide monomer to pH 10-11 and adding thereto an alkali or alkali earth metal borohydride at a temperature of -10 to 25°C so as to convert the residual free aldehyde in the equilibrium mixture to the corresponding alcohol.
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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 23, 1994 and granted February 1, 2000. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended February 23, 2014.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by February 23, 2016.
- 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.