| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method that purifies a long chain dicarboxylic acid or a salt thereof without using an organic solvent. <P>SOLUTION: The method comprises as follows. A crude long chain dicarboxylic acid is dissolved to water by alkali, decolored by a decolorant, acidified to 1-2.5 of pH, and crystallized. The obtained solid, in which this crystal is performed with heating/filtering in the water of 60-100°C, is resuspended to water. Subsequently the mixture is heated by the higher temperature than 100°C in a high pressure condition, and then cooled to be crystallized. As a result, the content of the impurity of protein, dye or the like in the product can be effectively decreased. The purity of the crystallized long chain dicarboxylic acid is higher than 99 wt%. <P>COPYRIGHT: (C)2013,JPO&INPIT |
