A process for the preparation of aliphatic oligocarbonate diols from dimethyl carbonate and aliphatic diols
CA 2293960 A1 · Owner: Bayer Aktiengesellschaft · Inventors: Langer, Reinhard; Hovestadt, Wieland; Melchiors, Martin
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The present invention relates to a process for the preparation of aliphatic oligocarbonate diols by, a) transesterifying dimethyl carbonate with aliphatic diols in the presence of soluble transesterification catalysts in a gas-liquid countercurrent apparatus to, form oligocarbonates until the degree of conversion of the initial dimethyl carbonate is more than 80% and, b) removing methanol and traces of dimethyl carbonate in an apparatus which generates gas bubbles in the oligocarbonates until the degree of capping of the terminal OH groups with methoxycarbonyl groups is less than 5%.
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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 January 4, 2000. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended January 4, 2020.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by January 4, 2022.
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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.