Preparation of sulphonated aromatic esters
CA 1290764 C · Owner: Roberts, David W. · Inventors: Thornthwaite, David W.; Madison, Stephen A.; Roberts, David W.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A process for preparing sulphonated aromatic esters of the group consisting of substituted or unsubstituted sulphonato-phenyl carboxylates and sulphonato-phenyl carbonates is disclosed, comprising the steps of: (1) preparing the unsulphonated aromatic ester; (2) sulphonating said unsulphonated aromatic ester; and (3) neutralising the acid-sulphonated aromatic ester in a non-aqueous organic solvent with an alkali metal earth alkali metal or ammonium carboxylate in an amount in excess over the amount needed to neutralise the sulphonic acid group(s) and any free or complexed SO3 present in the product mixture from the sulphonation reaction. Preferred neutralising agent is sodium acetate; …
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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 October 15, 1991. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended October 15, 2008.
- 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.