PROCESSES FOR RECOVERING CITRIC ACID

摘要

Described are preferred processes for recovering citric acid from a medium i n which it is contained. The citric acid is rec- overed both effectively and in a form which is readily purifiable. In one preferred process, the citric acid-containing medium is contacted with a solid-phase free base resin having tertiary amine groups to adsorb the citric acid. The citric acid is then desorbed by displacement with a stronger acid, and a citric acid-containing fraction is collected substantially free from contamination by the stronger acid. In another preferred process, a citric acid-containing medium is contacted with a solid-phase polymer having pyridine functions to adsorb citric acid, the contacting being at a temperature below about 40.degree.C. Adsorbed citric acid is then de- sorbed with hot H2O at a temperature of at least about 75.degree.C. Unnecessary impurities such as those arising from the use of organic solvent or throughput inorganic acid desorbents are thereby avoided while at the same time achieving a commercial- ly attractive recovery of the citric acid. Additional preferred modes and process features are also described.