Physical and Reactive Extraction Equilibria of Penicillin G in a Hydrogen-Bond Acceptor Solvent System

Abstract

Physical and reactive extraction equilibria of penicillin G were investigated experimentally and theoretically in the existence of n-butyl acetate as a hydrogen-bond acceptor solvent. Physical extraction equilibrium experiments were carried out varying the pH of aqueous phase and overall penicillin concentration. We compared the experimental data with the calculated results from four physical extraction equilibrium models suggested here and obtained the most reasonable model. Also, penicillin G was reactively extracted using Amberlite LA-2 in n-butyl acetate. The experimental variables were pH of the aqueous phase, overall amine concentration, and overall penicillin concentration. A combined equilibrium model including our physical extraction equilibrium expression and the reactive extraction equilibrium expression suggested by Reschke and Schügerl was used so as to analyze the current reactive extraction equilibrium system. The calculated results from the reactive extraction equilibrium model were in good agreement with the experimental data.

Facilitated Transport of Penicillin G by Bulk Liquid Membrane with TBP as Carrier

“…Also, when n-butyl acetate or MIBK is used as a diluent, the transport efficiency is high. Because the penicillin G-TBP complex, TBP m (HP) n , is more soluble in a polar solvent than in a nonpolar solvent [5,8].…”

“…Although many types of complex extractants, such as aminebased solvent, aliphatic alcohol, and phosphorus ester, etc. had been applied to recover penicillin G in many studies [7][8][9][10][11], the reactive extraction process had not been adopted in industrial process because the consumption of solvent in the extraction process is large and the solvent is usually expensive [7].…”

Extraction equilibria of penicillin G in four different types of organic solvent systems

“…Also, the subscripts, org and aq denote organic and aqueous phases, respectively. By using an overall material balance of penicillin G [4], the degree of extraction (E) is written by…”

“…In the case of n = 3, the degree of extraction is denoted by using Eqs. (2) and (4), and an overall material balance of penicillin G as follows [4]:…”

“…It has been physically extracted with n-butyl acetate at low pH in conventional solvent extraction processes, but loss of penicillin G due to its instability, high solubility of the organic solvent into aqueous feed phase and a low recovery yield of penicillin G have not made the processes economical. In order to overcome the disadvantages of the physical extraction process, therefore, chemical reaction between penicillin G and amines has been introduced into various liquid-liquid extraction and liquid membrane systems [1][2][3][4][5][6][7] since Reschke and Shü gerl [8][9][10] pioneered reactive extraction of penicillin G using amine extractants. Equilibrium expressions of the chemical reaction are dependent on organic solvent types [2,4], but they have not been rightly used in some penicillin extraction systems, thereby resulting in a wrong transport mechanism of penicillin G.…”