Separation process of citric acid with tertiary amines/diluents in supercritical CO2

Reactive extraction of citric acid was investigated at atmospheric and supe rcritical. conditions. The most suitable diluent and amine from among the t ertiary amines and eight different diluents were determined at atmospheric conditions. The distribution coefficient values obtained with Hostarex A 32 7 were higher than those of Alamine 336. The selected amine (Hostarex A327) and the diluent (Oleyl alcohol) were used for reactive extraction of citri c acid at supercritical conditions. Separation yields of citric acid were o btained in the temperature ranges of 308 to 328 K and in the pressure range s of 80 to 180 bars in a supercritical. extraction system which is continuo us in terms of CO2. It was found that separation yield decreased with incre asing extraction pressure at all investigated temperatures. The highest sep aration yield (28%) was obtained at near the critical pressure. It was obse rved that the separation yield did not change with increasing temperature i n the pressure range of 80 to 180 bars.