CARBOXYLATSYRNING

A method for preparing a carboxylic acid by acidification of a liquid feed including a carboxylate salt, which method includes the steps of providing a liquid feed including magnesium carboxylate; providing a gas feed including gaseous hydrogen chloride; and acidifying the carboxylate to carboxylic acid by bringing the liquid feed into contact with the gas feed, thereby forming a liquid effluent including carboxylic acid and magnesium chloride, wherein the gas feed including gaseous hydrogen chloride is derived from a thermal decomposition step wherein an aqueous liquid including magnesium chloride is subjected to a temperature of at least 300° C., thereby decomposing magnesium chloride into magnesium oxide and hydrogen chloride, thus obtaining a solid including magnesium oxide and a gas comprising gaseous hydrogen chloride.