Patent ID: 9079857
Filing Date: 2015-07-14
Classification: C07D,Y02P

Abstract:
1. A process for preparing an alkali metal pyrithione comprising the steps of: adding pyridine N-oxide, at least one sulfurination agent and at least one base agent to a solvent blend, the solvent blend containing a surfactant and a first organic solvent, to form a first reaction mixture; wherein the sulfurination agent and the base agent are added in a predetermined molar ratio relative to the pyridine N-oxide; heating the first reaction mixture to a first predetermined temperature; cooling the first reaction mixture to a second predetermined temperature; adding an aqueous solution to the cooled reaction mixture to form a two phase liquid having an organic layer and an aqueous layer; filtering the aqueous layer or the two phase liquid to obtain a filter cake and a filtrate; separating the aqueous layer from the two phase liquid before or after filtering; sparging the aqueous layer or the filtrate with a chemically inert gas into a trap, the trap comprising an alkali metal hydroxide to form a second reaction mixture; and isolating the alkali metal pyrithione from the second reaction mixture.