Industrial & Engineering Chemistry Research, Vol.49, No.23, 12022-12030, 2010
Selective Separation of Cephalexin from Multiple Component Mixtures
Supported liquid membranes (SLMs) with strip dispersion and carrier, Aliquat 336, were used for the selective recovery of Cephalexin from simulated enzymatic solutions for Cephalexin synthesis. For the Cephalexin-containing feed solution, pH control methods using constant NaOH titration, carbonate buffer, and phosphate buffer were compared. Carbonate buffers with concentrations of 0.05 and 0.10 M gave the highest extraction and recovery, in which recovery for both cases was over 99%. Optimal extraction of Cephalexin from feed solutions containing equimolar concentrations of 7-amino-3-desacetoxicephalosporanic acid (7-ADCA) occurred at a feed solution pH = 9.5, resulting in a separation factor of 12.1. The recovery of Cephalexin from solutions containing 7-ADCA, phenylglycine amide (PGA), and phenylglycine (PG) was also demonstrated. Improved Cephalexin extraction was achieved at a feed pH = 8.0 when compared to a feed pH = 9.5 due to high coextraction of PG at the latter. At a feed pH = 8.0 and a feed solution composition of 15, 15, 15, and 3 mM for Cephalexin, 7-ADCA, PG, and PGA, respectively, an initial Cephalexin flux of 3.1 g/(m(2) h) was achieved.