Separation of FTC-Ester Enantiomers Using a Simulated Moving Bed

Abstract

A simulated moving bed (SMB) process has been developed for the resolution of racemic mixtures of cis-(()-FTC-ester, a precursor of a potential anti-HIV drug. Chiralpak AD was chosen as the stationary phase and methanol as the mobile phase for this study. The nonlinear standing wave design method was used to determine the zone flow rates and step times of the SMB process. Computer simulations and several laboratory-scale SMB experiments were conducted to test the proposed SMB processes. Extracolumn dead volume (DV) had significant effects on the performance of the laboratory-scale SMB with small columns (10 × 1 cm). Nonuniformly distributed DV was considered in the design and simulations. Different pump arrangements were investigated to reduce the DV effects. High purity (99.8%, or 99.6% e.e.) and high yield (98.9%) were achieved in the SMB experiments. If mass-transfer effects were ignored in the design, the yield would have been lower than 93%.

Standing wave optimization of SMB using a hybrid simulated annealing and genetic algorithm (SAGA)

“…This separation was originally examined by Xie et al (2003a), where the reported stationary phase, mobile phase, isotherm parameters, and mass-transfer parameters appear in Table 1. More recently, an in-depth analysis of this separation problem was presented in Cauley et al using SWAT optimization tool (Cauley et al 2006), which will be used as a benchmark in this paper.…”

“…Furthermore, unlike methods that rely on the equilibrium theory, SWD does not require time-consuming simulations of SMB processes to ensure that the purity and yield requirements are satisfied. Many experimental studies and computer simulations based on a detailed rate model (VERSE) have verified that SWD guarantees the desired purity and yield for nonideal SMB systems with two or more columns in each zone (Wu et al 1998;Xie et al 2002Xie et al , 2003a.…”

Simulated moving bed multiobjective optimization using standing wave design and genetic algorithm

“…The velocity differences that are needed to focus the waves, and to maintain certain desired product purity and yield, have been derived and verified experimentally for nonideal systems in several previous studies. 25,26,28,29 …”

“…The maximum pressure drop in a given system depends on zone configuration and pump configuration. 28,30 A conservative estimate was made by assuming that the desorbent pump controls the flow rates from Zones I to IV. Then, the overall system pressure can be calculated by summation of the pressure drop in each zone, which was calculated from the Ergun equation.…”

Partial port-closing strategy for obtaining high throughput or high purities in a four-zone simulated moving bed chromatography for binary separation

“…It has thus been of noteworthy applications in petrochemical, biochemical, and pharmaceutical industries [2,[5][6][7]. Fig.…”