Selective Separation of Cephalexin from Multiple Component Mixtures

• Published in: Industrial & engineering chemistry research Vol. 49; no. 23; pp. 12022 - 12030
• Main Authors: Vilt, Michael E, Ho, W. S. Winston
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01.12.2010
• Subjects: Applied sciences; Chemical engineering; Exact sciences and technology; Separations
• ISSN: 0888-5885; 1520-5045
• DOI: 10.1021/ie100073w

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/(m2 h) was achieved.