On ion-exchange resins

Pharmaceutical. Ion-exchange resins are useful in both the production of pharmaceuticals (qv) and the oral adrninistration of medicine (32). Antibiotics (qv), such as streptomycin [57-92-17, neomycin [1404-04-2] (33), and cephalosporin C [61-24-5] (34), which are produced by fermentation, are recovered, concentrated, and purified by adsorption on ion-exchange resins, or polymeric adsorbents. Impurities are removed from other types of pharmaceutical products in a similar manner. Resins serve as catalysts in the manufacture of intermediate chemicals. 

After the second extraction/stripping cycle, the plutonium is concentrated by evaporation or by preferential adsorption (qv) on ion-exchange resins. As in the case for uranium, the newer faciHties, such as THORP, use only a single purification step. 

Anion exchange resins. Should be conditioned before use by successive washing with water, EtOH and water, and taken through two OH"—H" "—OH" " cycles by successive treatment with N NaOH, water, N HCl, water and N NaOH, then washed with water until neutral to give the OH" form. (See commercial catalogues on ion exchange resins). 

Loss on ion-exchange resin (equivalent decolorization use to bone char) 0.03%... 

Wade, H. E., The fractionation of phosphate esters on ion-exchange resin by a new system of pH-gradient elution, Biochem.., 77, 534, 1960. 

Catalysts for hydrogenation can be also supported on ion exchange resins. For example, rhodium(III) chloride, attached to a 3-carboxy-butenolic acid/DVB cation exchange resin with... 

The plutonium concentration in marine samples is principally due to environmental pollution caused by fallout from nuclear explosions and is generally at very low levels [75]. Environmental samples also contain microtraces of natural a emitters (uranium, thorium, and their decay products) which complicate the plutonium determinations [76]. Methods for the determination of plutonium in marine samples must therefore be very sensitive and selective. The methods reported for the chemical separation of plutonium are based on ion exchange resins [76-80] or liquid-liquid extraction with tertiary amines [81], organophosphorus compounds [82,83], and ketones [84,85]. 

Amino acid analysers based on ion exchange resins are available commercially. These achieve good separations of amino acid mixtures. Fluorescent derivatives of separated amino acids constitute a very sensitive means of detecting these compounds in seawater [256,258]. Fluorescent derivatives that have been studied include o-phthalaldehyde [259], dansyl [260], fluo-rescamine [261], and ninhydrin [261]. 

Klyueva and Gel perin have compared the equilibrium distribution curves for the adsorption of neomycin on ion-exchange resins from both pure solutions and typical fermentation broths. 

Some studies and patents related to the etherification reaction between glycerol and isobutene are available in the literature, which report the production of the ethers with various catalysts, such as zeolites [19], ion-exchange resins [20, 21] and some homogeneous catalysts, e.g., p-toluene sulfonic acid [21, 22] and methane sulfonic acid [22], Recent studies, however, have concentrated on the etherification of glycerol with isobutene on ion-exchange resins [8, 23]. 

TBA and isobutene have been compared as the etherifying agent at 60 °C. The initial molar ratio of isobutene to glycerol was 4.0 with Amberlyst A35 as the catalyst. The conversion of glycerol is lower when etherified with TBA than when etherified with isobutene. More hydrocarbons are formed with isobutene than with TBA. But, with TBA, mainly monoethers are formed and valuable triethers are formed only in small amounts. In addition, TBA dehydrates to water, which has an inhibition effect on ion-exchange resin catalysts [23],... 

The Separation of Rare-Earths, Fission Product, and other Metal Ions and Anions by Adsorption on Ion-Exchange Resins. J. Amer. chem. Soc.- 69, 2769—2881 (1947) (15 papers). 

El Haji, T. Masroua, A. Martin, J.-C. Descotes, G. Synthesis of 5-(hydroxymethyl)-furan-2-carboxaldehyde and its derivatives by acid treatment of sugars on ion-exchange resins, Bull Soc. Chim. Fr., 1987, 855-860. 

Small, H. and Bremer, D. N. Sorption of nonionic solntes on ion exchange resins bearing amphiphilic connter ions. Environ. Sci. TechnoL, 3(4) 361-3367, 1964. 

The proteins known today as linker or HI histones were initially described as the abundant lysine-rich nuclear proteins that could be separated by chromatography on ion exchange resin from other major basic nuclear proteins known today as core histones (for review see Refs. [1,2]). During gel electrophoresis of histones the HI fraction migrated as the slowest and most heterogeneous band. Upon the discovery of nucleosomal organization of chromatin in the mid 1970s it turned out that linker histones are not involved in the assembly of the nucleosomal protein core, but bind to DNA between nucleosomes (hence their name). 

Many other modifications, particularly of the Rh and Mel catalysed carbonylation of MeOH, have been proposed and some of these have been operated commercially or may have been tested at significant pilot plant scale. These include, for example, the use of phosphine oxide species such as PPh30 [20] as promoters and systems involving immobilizing the Rh on ion exchange resins [21]. Numerous examples of ligand modified catalysts have been described, particularly for Rh, though relatively few complexes have been shown to have any extended lifetime at typical process conditions and none are reported in commercial use [22, 23]. The carbonyl iodides of Ru and Os mentioned above in the context of the Cativa process are also promoters for Rh catalysed carbonylation of MeOH to AcOH [24]. 

Most home water softeners are based on ion-exchange resins. The first ion-exchange materials used in softening water were naturally occurring polymeric aluminum silicates called zeolites. At present, synthetic zeolites are also used for this purpose. Today, most... 

Still the search continued. In 1954 several laboratories reported die isolation and study of elements 99 and lOO. A group at Berkeley gave some details of the discovery of 99 (96), and soon afterwards of 100 (97). Only minute amounts of these substances were obtained, but the elution sequences on ion-exchange resins served to identify them. Physical properties were reported from both Berkeley ( 98) and the Argonne Laboratories at Arco, Idaho (99). The authors of all those papers added notes to their reports stating that unpublished information still remained, and that no attempt should be made to prejudge questions of priority of discovery on the basis of the published papers. 

Ison, A.P., Dunnill, P., Lilly, M.D., Macrae, A.R. and Smith, C.G. (1990) Enzymatic interesterification of fats Immobilization and immimogold localization of hpase on ion-exchange resins. Biocatalysis, 3, 329-342. 

Larsen, A M., Barfoed, M. and Ursin, C. (1995) Localisation and concentration profiling of immobilized " C-labelled lipase on ion-exchange resin by micro autoradiography. European Conference of Biotechnology, MAP-120. 

Analysis of glycosaminoglycan hydrolyzates is often complicated by the presence of basic and acidic glycoses, in addition to neutral monosaccharides. Adsorption chromatography on silica gel was used to classify such a hydrolyzate, and the neutral fraction was shown to contain D-glucose, D-galactose, and D-mannose.288 Separation on ion-exchange resins may also be used.51,149 The resolution of the acidic and basic fractions is discussed in Sections IX (p. 71) and X (p. 78). 

When polysaccharides contain uronic acids, it is often convenient to separate the acidic oxidation-products on ion-exchange resins and to generate the lactones, which are then reduced. Applied to... 

The analyte must be efficiently recovered. The usual mechanism for solvent desorption is selective displacement of the analyte. Selective displacement occurs as a more polar solvent displaces a less polar one on charcoal, just as a more active ion displaces a less active one on ion exchange resins. CS2 is frequently used to recover substances from charcoal, but simple alcohols cannot be displaced from charcoal by CS2, and it is necessary to add l%-5% of another alcohol to the CS2 to facilitate desorption. Frequently, low recoveries can be increased by increasing the quantity of solvent, if analytical sensitivity permits. Prospective solvents may be chosen based on polarity or solubility of the analyte. 

Two classical examples are given here, based on ion exchange resins ... 

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