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Expired Canadian patentCanada

Electrochemical generation of dinitrogen pentoxide in nitric acid

CA 2005663 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: Bagg, Greville E. G.

CIPO record

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Its claims, description and drawings are in the Canadian Patents Database.

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Abstract From the Canadian patent

A two-stage method of producing N2O5 in nitric acid from N2O4 in nitric acid consists of a first production stage in which the anodic oxidation of N2O4 in nitric acid and cathodic reduction of nitric acid are separated by a non-ionic or anionic ion exchange membrane, and a second production phase in which the product of the first stage anodic reaction is subjected to further anodic oxidation, the anodic and cathodic reactions being separated by a cationic ion exchange membrane. The use of a cationic membrane in the second stage promotes, through leakage of N2O4 to the catholyte an increase in N2O5 concentration and decrease in N2O4 concentration within the anolyte acid whilst avoiding a …

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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 December 15, 1989 and granted December 14, 1999. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended December 15, 2009.
  • A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by December 15, 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.
FiledDecember 15, 1989
GrantedDecember 14, 1999
Term endedDecember 15, 2009
Patent numberCA 2005663 C
Classification (IPC)C25B1/00 +1 more

Timeline

Timeline From CIPO dates

1990199219941996199820002002200420062008Application filedDec 15, 1989Patent grantedDec 14, 1999Term endedDec 15, 2009

Sources & verification

Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.