392. The absorption of some organic bases by carboxylic acid ion-exchange resins. Part I. Equilibrium studies

1952 ◽  
pp. 2111 ◽  
Author(s):  
L. Saunders ◽  
R. S. Srivastava
Keyword(s):  
Carboxylic Acid ◽  
Ion Exchange ◽  
Ion Exchange Resins ◽  
Equilibrium Studies ◽  
Organic Bases ◽  
Exchange Resins

The isolation and identifiction of 5-Hydroxypiperidine-2-carboxylic Acid from Leucaena glauca Benth

1957 ◽  
Vol 10 (4) ◽  
pp. 484 ◽  
Author(s):  
MP Hegarty
Keyword(s):  
Carboxylic Acid ◽  
Ion Exchange ◽  
Ion Exchange Resins ◽  
Isolation And Identification ◽  
Synthetic Compounds ◽  
Chromatographic Techniques ◽  
Imino Acid ◽  
Exchange Resins

The isolation and identification of 5-hydroxypiperidine-2-carboxylic acid from the leaves of L. glauca Benth. by procedures using ion-exchange resins and chromatography are described. This imino acid has been synthesized and the resulting diastereo-isomers separated by chromatographic techniques. The stereochemistry of the natural and the synthetic compounds is discussed.

Equilibrium studies of phenylalanine and tyrosine on ion-exchange resins

2005 ◽  
Vol 60 (18) ◽  
pp. 5022-5034 ◽  
Author(s):  
Maria João A. Moreira ◽  
Licínio Manuel G.A. Ferreira
Keyword(s):  
Ion Exchange ◽  
Ion Exchange Resins ◽  
Equilibrium Studies ◽  
Exchange Resins

Molecular sorption of benzoic acids on ion-exchange resins: sorption equilibrium studies

1982 ◽  
Vol 244 (2) ◽  
pp. 241-245 ◽  
Author(s):  
S.L. Bafna ◽  
B.V. Kamath ◽  
M.B. Patel ◽  
S.S. Kazi ◽  
M.C. Doshi ◽  
...  
Keyword(s):  
Ion Exchange ◽  
Ion Exchange Resins ◽  
Benzoic Acids ◽  
Sorption Equilibrium ◽  
Equilibrium Studies ◽  
Molecular Sorption ◽  
Exchange Resins

Die Hydratation von Carboxyl-Gruppen in Ionenaustauscherharzen Eine dielektrische Untersuchung / The Hydration of Carboxylic Acid Groups in Ion Exchange Resins A Dielectric Investigation

1970 ◽  
Vol 25 (8) ◽  
pp. 808-820 ◽  
Author(s):  
K. Bunzl ◽  
B. Sansoni
Keyword(s):  
Dielectric Constant ◽  
Carboxylic Acid ◽  
Ion Exchange ◽  
Water Content ◽  
Ion Exchange Resins ◽  
Dielectric Measurements ◽  
Proton Mobility ◽  
Carboxylic Acid Groups ◽  
Carboxylic Groups ◽  
Exchange Resins

The hydration of carboxylic acid groups in ion exchange resins was studied by means of dielectric measurements. For three resins carrying carboxylic groups with quite different pK-values the dielectric constant and the dielectric loss were measured as a function of frequency, water content, and temperature. A comparison of their behaviour showed that the observed dielectric dispersion is due to a Maxwell-Wagner mechanism. In the course of the water adsorption the resin with very weak carboxylic acid groups exhibited a discontinuity of the dielectric constant, if one molecule of water was attached to two carboxylic groups. This can be explained by assuming that the carboxylic groups which are connected by hydrogen bonds in the dry state begin to dissociate at the above mentioned water content. As a consequence, the formation of H5O2⊕-complexes becomes possible. The corresponding increase of the proton mobility leads to the observed Maxwell-Wagner effects. Hydration structures of the carboxylic acid groups below and above this critical water content are proposed.In the case of the two other resins with higher acidity of the carboxyl groups no discontinuity during water sorption could be observed. The mobility of the proton and hence the Maxwell-Wagner effects could thus be observed at much lower water contents.The appreciable differences in the shapes of the corresponding wateradsorption isotherms are in agreement with conclusions from the dielectric measurements.

Embedding Procedure for Water Swollen Samples

1970 ◽  
Vol 28 ◽  
pp. 504-505
Author(s):  
Ann M. Thomas ◽  
Virginia Shemeley
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Ion Exchange ◽  
Structural Changes ◽  
Cross Linking ◽  
Ion Exchange Resins ◽  
Transmission Electron ◽  
First Pass ◽  
Exchange Resins

Those samples which swell rapidly when exposed to water are, at best, difficult to section for transmission electron microscopy. Some materials literally burst out of the embedding block with the first pass by the knife, and even the most rapid cutting cycle produces sections of limited value. Many ion exchange resins swell in water; some undergo irreversible structural changes when dried. We developed our embedding procedure to handle this type of sample, but it should be applicable to many materials that present similar sectioning difficulties.The purpose of our embedding procedure is to build up a cross-linking network throughout the sample, while it is in a water swollen state. Our procedure was suggested to us by the work of Rosenberg, where he mentioned the formation of a tridimensional structure by the polymerization of the GMA biproduct, triglycol dimethacrylate.

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