Advanced solid phase processes

Abstract This review covers recent advances in the field of radical chemistry on solid phase. Intermolecular processes using both immobilized radicals with solution-phase acceptors and immobilized acceptors with radicals in solution are discussed, as are radical cyclization reactions on polymer supports. Progress in the development of solid-phase asymmetric radical processes and the design of linkers cleaved by radical processes are also discussed. 

During the last ten years there have been several notable advances in the development of ultra high modulus polyethylene and polypropylene. This has been achieved most simply by tensile drawing , but also by hydrostatic extrusion , ram extrusion and die drawing all of which are solid phase deformation processes. In polyethylene, an alternative approach has been the production of fine ultra high modulus fibres from dilute solution, either by crystallisation in an elongational flow field or by stretching fine fibres spun to form a gel from dilute or reasonably dilute solution, 13 ... 

The theory on the level of the electrode and on the electrochemical cell is sufficiently advanced [4-7]. In this connection, it is necessary to mention the works of J.Newman and R.White s group [8-12], In the majority of publications, the macroscopical approach is used. The authors take into account the transport process and material balance within the system in a proper way. The analysis of the flows in the porous matrix or in the cell takes generally into consideration the diffusion, migration and convection processes. While computing transport processes in the concentrated electrolytes the Stefan-Maxwell equations are used. To calculate electron transfer in a solid phase the Ohm s law in its differential form is used. The electrochemical transformations within the electrodes are described by the Batler-Volmer equation. The internal surface of the electrode, where electrochemical process runs, is frequently presented as a certain function of the porosity or as a certain state of the reagents transformation. To describe this function, various modeling or empirical equations are offered, and they... 

Selected examples of these and related applications are authoritatively discussed in the chapters by K.C. Nicolaou et al. (epothilone libraries) and S.E. Gibson and S.P. Keen (cross metathesis processes on solid phase) in this monograph. For some further advancements, the reader is referred to the recent literature [45]. 

The most important solid-phase separation materials for column-based separations in modern radioanalytical chemistry are extraction chromatographic materials, and these have been particularly important in automated radioanalytical chemistry. Solid-phase extraction materials based on the covalent attachment of ligands to solid supports also exist, and they have found application in large-scale separation processes for waste or effluent treatment.22 25 They have been commercialized as Analig or SuperLig materials by IBC Advanced Technologies (American Fork, UT). However, they are less well characterized or used for small-column analytical separations. 

Computational studies have advanced the study of the solid phase of water and of the interfacial region where the phase transition occurs [1-5]. As water exhibits very unusual properties in the liquid phase, it also exhibits peculiar properties in the solid phase as well. Much about the structure of ice is known from x-ray diffraction experiments or computational studies. Some experiments have been performed on the interfacial region between the liquid and solid phase of water to understand the freezing process, but additional studies are still needed to characterize the... 

A number of automatic peptide synthesizers are commercially available now 40). However, in spite of all these mechanical and electronical advances in the automation of solid phase synthesis, as Barany and Merrifield state in their review on the solid phase peptide synthesis11), the limiting factor continues to be the chemistry of the process and automation can reach its full potential only when the assorted chemical difficulties are under control. 

Kobayashi and co-workers began to use the van der Waals and Platteeuw theory in the 1960s to predict hydrate formation in ternary systems. Parrish and Prausnitz extended the method to prediction of hydrate incipient formation in natural gas systems causing the widespread industrial adoption of the van der Waals and the Platteeuw statistical method. Many academic (e.g.. Holder and co-workers ) and commercial programs (e.g., D.B. Robinson, and Associates ) enabled the gas and oil industry to predict thermodynamic conditions at the incipient formation point, and thereby to prevent hydrate formation in industrial processes. All of the errors in the van der Waals and Platteeuw theory were placed in the solid phase. It may be argued that the theory s unusual success in prediction inhibited motivations for advances in hydrate phase measurements. 

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