RECOVERY OF CARBOXYLIC ACID FROM THEIR MAGNESIUM SALTS BY PRECIPITATION USING HYDROCHLORIC ACID, USEFUL FOR FERMENTATION BROTH WORK-UP

摘要

The invention provides a method for preparing a carboxylic acid, which method comprises the steps of providing magnesium carboxylate, wherein the carboxylic acid corresponding with the carboxylate is selected from the group consisting of 2,5-furandicarboxylic acid, fumaric acid, adipic acid, itaconic acid, citric acid, glutaric acid, maleic acid, malonic acid, oxalic acid and fatty acids having more than 10 carbon atoms; acidifying the magnesium carboxylate with hydrogen chloride (HC1), thereby obtaining a solution comprising carboxylic acid and magnesium chloride (MgCb); optionally a concentration step, wherein the solution comprising carboxylic acid and MgCb is concentrated; precipitating the carboxylic acid from the solution comprising the carboxylic acid and MgCb, thereby obtaining a carboxylic acid precipitate and a MgCb solution. The inventors found that the addition of HC1 to a magnesium salt of the carboxylic acid and subsequent precipitation of the carboxylic acid from the solution leads to a very efficient separation of the carboxylic acid from a magnesium carboxylate solution.