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Expired Canadian patentCanada

Two-stage dilute acid prehydrolysis of biomass

CA 2065548 C · Owner: Torget, Robert W. · Inventors: Torget, Robert W.; Grohmann, Karel

CIPO record

Overview

Drawings and full text

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

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Abstract From the Canadian patent

A two-stage dilute acid prehydrolysis process on xylan containing hemicellulose in biomass is effected by: treating feedstock of hemicellulosic material comprising xylan that is slow hydrolyzable and xylan that is fast hydrolyzable under predetermined low temperature conditions with a dilute acid for a residence time sufficient to hydrolyze the fast hydrolyzable xylan to xylose; removing said xylose from said fast hydrolyzable xylan and leaving a residue; and treating said residue having a slow hydrolyzable xylan with a dilute acid under predetermined high temperature conditions for a residence time required to hydrolyze said slow hydrolyzable xylan to xylose.

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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 April 7, 1992 and granted February 26, 2002. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended April 7, 2012.
  • A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by April 7, 2014.
  • 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, 1992
GrantedFebruary 26, 2002
Term endedApril 7, 2012
Patent numberCA 2065548 C
Classification (IPC)C13K13/00

Timeline

Timeline From CIPO dates

1993199519971999200120032005200720092011Application filedApril 7, 1992Patent grantedFeb 26, 2002Term endedApril 7, 2012

Sources & verification

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