Process for purifying isophthalic acid by crystallization
CA 2331805 A1 · Owner: Gtc Technology Inc. · Inventors: Lee, Fu-Ming; Lamshing, Wiston; Wytcherley, Randi Wright
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Disclosed is a method for preparing isophthalic acid from metaxylene and especially for purifying crude isophthalic acid (IPA) produced in the course of such method, or otherwise, from a liquid dispersion thereof also containing impurities selected from unreacted starting materials solvents, products of , side reactions and/or other undesired materials. The purifying portion of the method comprises the step of: (1) filtering the dispersion to form a crude IPA filter cake; (2) dissolving the filter cake in a selective crystallization solvent at an elevated temperature to form a solution; (3) crystallizing purified IPA from the solution in the crystallization solvent by reducing the …
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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 20, 1999. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended April 20, 2019.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by April 20, 2021.
- 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.