| 摘要 |
Crude aqueous malic acid liquor is purified from saturated organic acid impurities by contacting with a basic anion exchange resin of a basicity to selectively adsorb the acid impurities. The liquor which may be that remaining from the crystallization of fumaric acid from the reaction mixture obtained by treatment of maleic acid may be treated preferably with a polystyrene resin containing aminomethyl substituents. Other resins such as cation-exchange resins and porous activated carbon adsorbent may also be used in further purification stages. |
