Separation Process Of Citric Acid with Tertiary Amines/Diluents in Supercritical CO2

Citric acid is the most widely used organic acid in the field of foods and beverages as an acidulant as well as in pharmaceutical and chemical products. Demand for citric acid has increased worldwide, including in Turkey. It is generally produced by surface or submerged fungal fermentation mainly with Aspergillus niger. However, the highest citric acid production has been obtained with the submerged fermentation method. Citric acid is typically purified by a firmly established process known as the method of calcium salt precipitation. Citric acid can be separated from fermentation broths by a series of precipitation and isolation reactions using Ca(OH)2 and H2SO4. However, this process contains several batch treatments, which require large amounts of chemical reagents and a considerable amount of heat. These negative factors have directed many investigators to find new techniques to separate or purify citric acid from fermentation broths. Recently, reactive extraction with amines and supercritical fluid extraction have been reported in the literature as a new technique. Reactive extraction has proven its applicability in the separation of fermented ∗To whom correspondence should be addressed.