| 摘要 |
PURPOSE:To reutilize a desorbed solution and efficiently obtain the titled solution, by treating a mother liquor after crystallizing and separating fumaric acid with active carbon, adsorbing the fumaric acid on the active carbon, heating the adsorbed fumaric acid at the adsorption temperature or above, desorbing the fumaric acid, cooling the resultant solution in a high concentration, crystallizing and separating the fumaric acid. CONSTITUTION:A solution containing fumaric acid is brought into contact with active carbon to adsorb the fumaric acid on the active carbon and water or a solution containing fumaric acid is used as a desorbing solution to heat the active carbon adsorbing the fumaric acid at a higher temperature than the adsorption temperature and desorb the fumaric acid from the active carbon into the desorbing solution. Thereby the aimed concentrated solution of the fumaric acid is obtained. Further, the resultant concentrated solution is cooled to crystallize and separate the fumaric acid. The separated solution can be reused in an isomerization step of maleic acid. The active carbon is economical, since performance thereof is hardly deteriorated even by repeating adsorption and desorption many times. The fumaric acid is in high purity and useful as a food additive.
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