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Expired Canadian patentCanada

Removal of selenium from urethane solutions

CA 1110827 A · Owner: Atlantic Richfield Company · Inventors: Shawl, Edward T.; Zajacek, John G.; Sheng, Ming N.

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Abstract From the Canadian patent

A method for the removal and recovery of selenium from a urethane solution containing selenium compounds which may be in the form of inorganic selenium and/or organoselenium compounds, which comprises contacting the selenium-containing urethane solution at a suitable temperature with an aqueous hydrogen peroxide solution and recovering the selenium from the resulting selenium compound enriched aqueous phase in a form suitable for reuse in the preparation of urethanes, the deselenized urethane remaining in the hydrocarbon and/or organic phase.

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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

  • Granted October 20, 1981. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended October 20, 1998.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledOctober 24, 1980
GrantedOctober 20, 1981
Term endedOctober 20, 1998
Patent numberCA 1110827 A
Classification (IPC)C01B19/00

Timeline

Timeline From CIPO dates

198119831985198719891991199319951997Application filedOct 24, 1980Patent grantedOct 20, 1981Term endedOct 20, 1998

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