Process for manufacturing high-purity o-toluic acid
CA 2016347 C · Owner: Takefumi, Tadayoshi · Inventors: Takefumi, Tadayoshi; Matsumoto, Shunichi; Tokura, Nobuyuki
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A process for manufacturing high-purity o-toluic acid from a partial oxidation product of o-xylene is disclosed. o- Toluic acid is widely used as a raw material for agricultural chemicals, medicines, polymerization initiators and the like. Depending on its use, 99% by weight or more purity is demanded for o-toluic acid. Hitherto, o-toluic acid having purity of higher than 99% by weight could not be obtained by fractionation, and purification by fractional crystallization was used. Fractional crystallization is however, an, expensive operation and not only gives a low yield of product but also results a large amount of waste water. The process disclosed herein gives an economical, commercial …
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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 May 9, 1990 and granted March 25, 1997. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended May 9, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by May 9, 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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Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.