Neutral complex extraction and synergistic extraction of macrolide antibiotics

Based on the theory of reactive extraction, new solvent systems were develo ped to replace butylacetate for extraction of macrolide antibiotics (erythr omycin, kitasamycin, spiramycin meleumycin etc.). A new neutral complex sol vent extraction system, fatty alcohol-kerosene (marked by El), was used for extraction of erythromycin, one of the macrolide antibiotics. The extracti on equilibrium equation is obtained, and the extraction distribution is as follows D = exp (-36.33 x 10(3)/RT + 18.77)[B]((o))(1.1)/(1 + 10(8.07-pH)) The effects of several parameters on extraction equilibrium were investigat ed. Furthermore,a new synergistic extraction system (marked by E2) was deve loped, in which another solvent was used as synergistic agent to replace th e diluent kerosene in the neutral complex extraction system. Based on these new extraction systems, an improved process for extraction of erythromycin was developed, showing remarkable advantages in technology and economics o wing to its low solvent consumption of 3 kg per billion unit compared with 9-10 for butylacetate. The recovery process of solvent from raffinate may b e eliminated.