Vergleich verschiedener verfahrenstechnischer Konzepte der präparativen Flüssigchromatographie

Abstract

Liquid chromatography utilising porous solid phases (adsorption chromatography) is one of the most powerful and versatile methods of modern analytical chemistry. Its widespread application is due in part to the development of a broad range of combinations of solid stationary and liquid mobile phase. Normal phase and reverse phase chromatography with pure and chemically modified silica gel, respectively, affinity chromatography, and ion chromatography can be cited as examples [1]. In addition to its use as an analytical method, chromatography is becoming increasingly important in the preparative‐scale isolation of pure substances in the pharmaceutical industry, in biotechnology, and in the production of fine chemicals. In many cases, the required purity criteria can only be met with chromatographic techniques, as in the resolution of racemates. From a process engineering viewpoint, a better understanding of concentration profile deformations caused by intended overloading of separation columns has recently been acquired [2]. In particular, this cncerns the description of displacement and entrainment effects associated with the competing adsorption. A series of alternative operating modes has been developed and used [3] for enhancing yields and productivities. In spite of a number of attempted comparative studies [4] there is a lack of quantitative information about optimized process. This article aims to compare four different process engineering concepts of preparative chromatography on the basis of a uniform theoretical model.

A Rigorous Model for Annular Chromatography

“…Further on, it could be experimentally shown, that the separation performance of annular and batch chromatography is comparable [5], enabling a simple scaleup from small batch columns to larger annular chromatographs. In case of dominating equilibrium and mass transfer effects, but negligible dispersion, it was also theoretically shown that the separation performance regarding productivity, yield and specific solvent consumption, is the same for both processes [11,12].…”

Chromatographic Reactors

“…The production rate of the rotating cylindrical annulus is comparable to that of the BCR [9]. The rotating annulus can be considered as a number of batch columns arranged in a circle and periodically charged with feed.…”

“…A distinction is made between models that take Vol. 9 Chromatographic Reactorsmass transfer resistance into account and models in which equilibrium between the solid and the fluid phase is assumed. By employing the model of axial dispersion, axial mixing along the column can be described.…”

Modeling of Simulated Moving‐bed Chromatography

“…by repeated injections or recycling chromatography, but in any case the disadvantages of product dilution and discontinuous operation remain [1][2][3]. Continuous techniques can be classifi ed into those where the inlets and outlets are fi xed whereas the stationary phase is moved and the ones where the inlets and outlets are moved along the stationary phase (see Fig.…”