Patent ID: 9309181
Filing Date: 2016-04-12
CPC Classification: C07C,C12P

Claim Text:
1. A method of producing an unsaturated carboxylic acid from a salt of a hydroxycarboxylic acid, the method comprising: providing an aqueous solution comprising a salt of a hydroxycarboxylic acid; concentrating the aqueous solution by heating the aqueous solution to a first temperature to remove water, optionally under reduced pressure, wherein the first temperature is lower than a temperature needed to split a salt from the salt of the hydroxycarboxylic acid; adding a solvent with a boiling point of 200° C. or higher to the aqueous solution; and heating the aqueous solution at a temperature lower than the boiling point of the added solvent to split a salt from the salt of the hydroxycarboxylic acid while simultaneously dehydrating the hydroxycarboxylic acid, thereby converting the hydroxycarboxylic acid to an unsaturated carboxylic acid, wherein the step of heating the aqueous solution to a first temperature to remove water is performed before adding the solvent with a boiling point of 200° C. or higher.