Fundamentals of the theory and practice of polymer gel-permeation chromatography as a method of chromatographic porosimetry

Novel synthetic access to 15- and 18-membered ring diaza-bibracchial lariat ethers (BiBLEs) and a study of sidearm-macroring cooperativity in cation binding

The esterification of fatty acids is an important pretreatment step in the production of biodiesel from low-cost raw materials. It was thus used as a model reaction in a study of the influence of concentration variations of the polar component (methanol) in a reaction mixture on the morphology and functioning of ion exchange catalysts. For a gel-type ion exchange catalyst, a decrease in the methanol concentration proved to have unambiguously negative effects, as it induced de-swelling of the polymer matrix and diminished the accessibility of the active centers. For macroreticular ion exchange catalysts, on the other hand, the drop in methanol concentration had a positive influence on the efficiency of the catalytic action mechanism of the acidic centers. This was due to the existence of some swelling-independent porosity, causing a shift from a general to a specific catalysis-like mechanism.

Working-state morphologies of ion exchange catalysts and their influence on reaction kinetics

Anomeric activation of thioglycosides and preparation of deoxyglycosides using polymer-bound iodate(I) complexes

Swollen-state morphology of a series of ion exchanger catalysts was analyzed by inverse steric exclusion chromatography. Correlation of the obtained information with data on activities of the catalysts for synthesis of bisphenol A (BPA) served for quantitative assessment of usefulness of various fractions of polymer mass of the examined ion exchangers for bisphenol A synthesis.

Relations between morphology and catalytic activity of ion exchanger catalysts for synthesis of bisphenol A

Can porosity properties of particles really be determined by inverse gel permeation chromatography

Influence of the polymer on an anionic activation reaction promoted by a supported crown ether

The influence of non macroporous and macroporous supports on a test reaction is studied. t-BuOH reacts with tetra O-acetyl bromoglucose in presence of silver nitrate and a supported crown ether. Two reaction products are formed. Yield and selectivity are affected by the morphology of the support. The selectivity depends on the crosslinking degree. This dependence is explained by the rigidity of the matrix and by the variation of steric hindrance.

J. Capillon

Papers

Can porosity properties of particles really be determined by inverse gel permeation chromatography

Influence of the polymer on an anionic activation reaction promoted by a supported crown ether

Importance of the texture of the resin in crown ether supported catalysis