Method of preparing dialkyl dicarbonates
CA 2004650 A1 · Owner: Akzo America Inc. · Inventors: Franklin, Ralph
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A dialkyl dicarbonate (dialkyl pyrocarbonate) is prepared by contacting an alkyl haloformate (such as ethyl chloroformate) with an alkali metal carbonate (such as potassium carbonate) in the presence of a catalytic amount of a crown ether (such as 18 crown 6) and a solvating amount of a solvent (such as acetonitrile). The process of the invention is easy to carry out, it does not employ particularly hazardous materials and provides a high yield of dicarbonate.
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 December 5, 1989. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended December 5, 2009.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by December 5, 2011.
- 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.