Absence of experimental evidence of a delta-shock in the system phenetole and 4-tert-butylphenol on Zorbax 300SB-C18.

We investigate the system consisting of phenetole (PNT) and 4-tert-butylphenol (TBP) in methanol-water (63:37 v:v) on a Zorbax 300SB-C18 column by characterising single component isotherms, by performing a large number of binary experiments of different types and by describing the experiments through simulations carried out using a novel, rather powerful competitive adsorption isotherm, that we call the generalized bi-Langmuir isotherm. This system is of great interest because it was previously reported to yield a new type of transition in nonlinear chromatography, the so-called delta-shock. Such transition had been discovered earlier through a theoretical analysis and confirmed by detailed simulations.

Three column intermittent simulated moving bed chromatography: 3. Cascade operation for center-cut separations.

A general design methodology for chromatographic three fraction separation by application of the three column intermittent simulated moving bed (3C-ISMB) cascade is proposed and experimentally validated by studying the purification of an intermediately retained stereoisomer of nadolol, from an equimolar mixture of its four stereoisomers. The theoretical part shows that the 3C-ISMB cascade can be easily designed by applying Triangle Theory. Moreover, a re-scaling approach for the second stage is proposed so as to account for the fact that the feed flow rates to stage 2 are generally higher as compared to stage 1 due to dilution in the latter.

Three-column intermittent simulated moving bed chromatography: 2. Experimental implementation for the separation of Tröger's Base.

The three-column intermittent simulated moving bed (3C-ISMB) process has been presented in the first part of this series [1]. A theoretical comparative analysis of the new process to intermittent simulated moving bed (I-SMB) demonstrated successfully the potential of the 3C-ISMB technology. Particularly, 3C-ISMB was shown to substantially outperform I-SMB in terms of productivity whilst maintaining high purity specifications and without significantly sacrificing solvent consumption.

Three column intermittent simulated moving bed chromatography: 1. Process description and comparative assessment.

The three column intermittent simulated moving bed (3C-ISMB) process is a new type of multi-column chromatographic process for binary separations and can be regarded as a modification of the I-SMB process commercialized by Nippon Rensui Corporation. In contrast to conventional I-SMB, this enables the use of only three instead of four columns without compromising product purity and throughput. The novel mode of operation is characterized by intermittent feeding and product withdrawal as well as by partial recycling of the weakly retained component from section III to section I.