Process for the preparation of 2-hydroxynaphthalene-6-carboxylic acid
CA 2124058 A1 · Owner: Hoechst Aktiengesellschaft · Inventors: Schmid, Jorg; Rittner, Siegbert; Ruffer, Hans-Martin
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Process for the preparation of 2-hydroxynaphthalene-6carboxylic acid, A process for the preparation of 2-hydroxynaphthalene-6carboxylic acid using potassium carbonate and CO at temperatures above 260°C and at a pressure of at least 10 bar comprises using 2-hydroxynaphthalene-3-carboxylic acid and/or 2-hydroxynaphthalene-3,6-dicarboxylic acid and/or their potassium salts and, if desired potassium, .beta.-naphtholate as starting materials. The process according to the invention enables a considerable inerease, by reusing the secondary products in, the product selectivity with regard to 2-hydroxynaphthalene-6-carboxylic acid.
Read the whole patent
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 20, 1994. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended May 20, 2014.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by May 20, 2016.
- 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
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.