Method of separating dinitrogen pentoxide from its solution in nitric acid
CA 2049014 C · Owner: The Secretary Of State For Defence In Her Britannic Majesty'S Government Of The United Kingdom Of Great Britain And Northern Ireland · Inventors: Salter, David A.; Bagg, Greville E. G.; Sanderson, Andrew J.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A method of separating N2O5 from its solution in nitric acid which comprises the steps of: (a) preparing, by the electrochemical oxidation of N2O4 in nitric acid, a nitric acid solution at a temperature of at least 10 °C containing at least 45, wt % of dissolved (N2O4 + N2O5) and having a dissolved N2O5: nitric acid ratio by weight of at least 1:3; and (b) cooling the acid solution to less than 8 °C until an N2O5 solvate precipitates froze solution. The main advantage of the invention is that it enables electrically-efficient electrochemical methods to be employed in the production of the acid solution from which the solute is recovered.
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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 November 20, 1990 and granted May 30, 2000. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended November 20, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by November 20, 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
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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.