Potential barrier chromatography

E Ruckenstein, V Lesins. Classification of liquid chromatographic methods based on the interaction forces The niche of potential barrier chromatography. In A Mizrahi, ed. Advances in Biotechnological Processes, Vol 8 Downstream Processes Equipment and Techniques. New York Alan R. Liss, 1988, pp 241-314. 

Rates of adsorption/desorption are calculated by considering Bora, double-layer, and van der Waals forces. Conditions exist where rates are highly sensitive to particle size, shape, and chemical constitution because diffusion over a potential barrier controls. On this basis, a new separation technique, called potential-barrier chromatography, is suggested. 

With potential barrier chromatography, the double layer is suppressed by the use of high ionic strength and the van de Waal s attractive force predominates. Large particles, due to their greater attraction to the packing, are retarded more than small ones and elute later. 

The potential importance of rotational dynamics about the aryl C-N bond in asymmetric Mizoroki-Heck cyclizations of o-iodoacrylanilides was highhghted in a recent study by Curran and coworkers [68]. Because of the presence of two ortho substituents, racemic ( )-acryl o-iodoanilide 117 could be resolved by preparative high-performance liquid chromatography, and the enantiomers were shown to have a barrier for interconversion of 26 kcalmol" (Scheme 16.30). Although these conformational stereoisomers would racemize readily at the elevated temperatures typically used in asymmetric Mizoroki-Heck... 

ABSTRACT. The paper examines the influence of interactions at polymer surfaces and interfaces on the properties of polymer systems, with emphasis on acid/base interactions. The method of inverse gas chromatography is used to evaluate the donor-acceptor interaction potential of components in polymer systems. The usefulness of the interaction parameters is established by their ability to rationalize diverse properties of polymer systems, including the adsorption of polymers on pigments, and the effectiveness of thermal stabilizers in pigmented polymers. Various strategies for controlling surface and interfacial interactions in polymer systems are reviewed, with emphasis placed on the ability of polymers to adopt various surface orientations and compositions. TTiese inherent surface modification effects are attributed to thermodynamic driving forces, and are shown to influence polymer adhesion, barrier and other properties dependent on surface and interfacial forces. 

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