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Expired Canadian patentCanada

Method for manufacture of phthalic anhydride

CA 1311740 C · Owner: Hara, Tadanori · Inventors: Hara, Tadanori

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Abstract From the Canadian patent

A method for the manufacture of phthalic anhydride by the catalytic oxidation of naphthlene and/ or ortho-xylene which comprises contacting a mixed gas containing naphthalene and/or ortho-xylene and a molecular oxygen-containing gas with a catalyst bed comprising a first catalyst packed on the upstream side of the flow of mixed gas and a second catalyst packed on the downstream side of the flow, wherein the first catalyst has carried on a nonporous inactive carrier a catalytically active component composed of 90 to 67% by weight of titanium dioxide, 8 to 30% by weight of vanadium pentoxide, 2 to 5% by weight of a cesium compound and 0.11 to 0.2 of cesium compound/vanadium pentoxide (molar …

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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 December 22, 1992. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended December 22, 2009.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledApril 7, 1988
GrantedDecember 22, 1992
Term endedDecember 22, 2009
Patent numberCA 1311740 C
Classification (IPC)C07C51/26 +2 more

Timeline

Timeline From CIPO dates

1989199219951998200120042007Application filedApril 7, 1988Patent grantedDec 22, 1992Term endedDec 22, 2009

Sources & verification

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