Oxidative secondary rhodium recovery process
CA 2058620 C · Owner: Nicely, Vincent A. · Inventors: Zoeller, Joseph R.; Cushman, Michael R.; Nicely, Vincent A.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Disclosed is a process for recovering rhodium catalyst values from ''tars'' formed during the preparation of acetic anhydride by the rhodium catalyzed carbonylation of a mixture of methyl iodide and methyl acetate and/or dimethyl ether. The disclosed process provides a means for the recovery of rhodium values which normally are not extracted from the tars by treating a methyl iodide solution of such tars with certain oxidants.
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 November 26, 1990 and granted January 11, 1994. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended November 26, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by November 26, 2012.
- 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.