Atmospheric pressure process for preparing pure cyclic esters
CA 1281729 C · Owner: E.I. Du Pont De Nemours And Company · Inventors: Bhatia, Kamlesh Kumar
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Abstract of the Disclosure, This invention relates to an improved process for preparing highly pure cyclic esters by heating a polymer of the corresponding .alpha.-hydroxy acid or its ester or a copolymer of .alpha.-hydroxy acid or its ester and a thermally stable polyether in the presence of an inert gas at atmospheric pressure. The cyclic ester is carried from the reaction with the inert gas to a solvent system.
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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
- Granted March 19, 1991. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended March 19, 2008.
- 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
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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.