The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 24, 1996
Filed:
Jun. 02, 1995
Paolo Vacca, Vado Ligure, IT;
Marco Frezzati, Savona, IT;
Minnesota Mining and Manufacturing Company, St. Paul, MN (US);
Abstract
A process for synthesizing carbamoyl pyridinium compounds is described, in which the pyridine ring carries a sulfoalkyl group. The process comprises reacting a pyridine sulfonic acid with a carbamoyl chloride in the presence of a tert.-amine compound in a ketone solvent. The reactants are highly soluble in the ketone solvent, while, on the contrary, the carbamoyl pyridinium compounds and the tert.-ammonium halides formed by the reaction are not soluble in the ketone solvent and can be recovered from the reaction mixture. In a subsequent washing step with a selective solvent, for example in methanol in which carbamoyl pyridinium compounds are not soluble but tert.-ammonium halides are highly soluble, substantially pure carbamoyl pyridinium compounds can be obtained in high yields.