Anion exchangers Amberlites , Dowex

Molybdenum Anion-exchange on Dowex 1-X8 resin or Amberlite GC-40 Spectrophotometry [497-500,... 

Aliphatic amine-type weak base anion exchangers Amberlites IR-45 and IRA-67 Dowex 3-x4A Permutit E Permutit A 240A (Rohm and Haas, USA) (Dow Chemical Co, USA) (Permutit AG, Germany) (Phillips and Pain-Vermorel, France)... 

To increase metabolite production in plant cell culture, various adsorbents have been used for the solid/liquid two-phase system. Activated charcoal, lipophilic carrier (RP-8), zeolite, nonionic exchange resin (Amberlite XAD-2, XAD-4, XAD-7, XAD-8), acidic cationic exchange resins (Dowex 50 W, Amberlite IRC-50, IRC-200), basic anion exchange resin (Dowex i 1X4-50, Amberlite IRA-93, IRA-400), mixed bed resin (TMD-8), and wofatite have all been examined as shown in Table 2. Before adsorbent is introduced to a vessel or bioreactor for this purpose, it should be pre-treated to activate the surface. As an example, the preparation of XAD-7 is detailed as follows. 

Displacements. For the displacement ArCH2X ArCHjCN, a strongly basic anion exchanger (Amberlite IRA-400 or Dowex 21 K) was first converted into... 

Trace amounts of molybdenum have been separated from natural waters by retention of the anionic Mo-thiocyanate complex on the anion-exchanger Dowex 1. Mixtures of 2 A/ HCIO4 and 1 M HCl are used for the elution [24]. The Mo-thiocyanate complex has also been concentrated on the anion exchanger Amberlite XAD [25,26], with the use of acetone as the eluent [25]. Molybdenum has been retained on anion-exchange columns from an HCl medium prior to being determined by the thiocyanate method [27-30]. Mo has been sorbed selectively (pH 3.5) on the anion exchanger Sephadex G-25, from which it can be eluted withEDTA [31]. 

Ion-exchange separations can also be made by the use of a polymer with exchangeable anions in this case, the lanthanide or actinide elements must be initially present as complex ions (11,12). The anion-exchange resins Dowex-1 (a copolymer of styrene and divinylbenzene with quaternary ammonium groups) and Amberlite IRA-400 (a quaternary ammonium polystyrene) have been used successfully. The order of elution is often the reverse of that from cationic-exchange resins. 

Separations research at the Rocky Flats Plant (United States) has found ways to significantly improve Pu recovery from HNO waste streams by using extraction chromatography. Several extractants, including TBP (tribu-tylphosphate), TOPO (tri- -octylphosphine oxide), DHDECMP (dihexyl N,N-diethylcarbamoylmethylenephosphonate), and CMPO (octylphenyl-N,N-diisobutylcarbamoylmethylphosphine oxide) and their mixtures supported on Amberlite XAD4 and anion exchange resins (Dowex 1x4 and Amberlite IRA 938), were evaluated for their ability to remove low concentrations of plutonium from 7 M acid nitric [71-73],... 

Ion exchangers (s. a. Amberlite, Anion exchangers. Cation Dowex)... 

Strong base anion exchangers Duolite A113 Duolite A116 Duolite A161 Amberlite 400 Amberlite 410 Amberlite 900 Dowex 1 Dowex 2 AG1 AGMP-1 ... 

Anionic exchanger Strong base -N+(CH3)3C1- -N+(CH3)3OH- Cl" OH" 1-14 1-14 NaCl NaOH Amberlite IRA 400, Amberlite IRA 425, Dowex 1, Dowex 21K, Permutit SK... 

Ion-exchange polymeric resins are the most important types of exchangers currently in use [113-123], The first, totally organic ion-exchange resin was synthesized in 1935 by Adams and Holmer, when they produced a phenol-formaldehyde cation-exchange resin and an amine-formaldehyde anion-exchange resin, both obtained with the help of condensation polymerization reactions [113], In 1944, D Alelio synthesized styrene-based polymeric resins, which could be modified to obtain both cationic- and anionic-exchange resins. The majority of the resins commercially applied currently are of this type, for example, Amberlite IR-20, Lewatit S-100, Permutit Q, Duolite, C-20, Dowex-50, and Nalcite HCR. 

Johns et al. (2000) reported an anion exchange technology using Amberlite or Dowex or other resins to isolate phytoestrogens from plant protein materials. Carbonate or bicarbonate was used as a counterion to avoid chlorides or alkali in the final product. Protein slurry was passed through the column at pH 6-8. The bound isoflavones were released with alcohols, organic solvents or acid or base solution. The protein isolate produced was essentially free of isoflavones. 

Strongly basic anion-exchange resins, such as Dowex 1 and Amberlite IRA-400, are mostly used in the separation and preconcentrations to be discussed. 

Aldehydes may be dimerized, either to p-hydroxy aldehydes or to a,P-unsaturated aldehydes, by the use of the anion-exchange resins Amberlite and Dowex. ... 

In this way Consden et al. (1948) and Drake (1947) separated glutamic and aspartic acid on columns of Amberlite IR.-4 (polyamine anion exchanger) maintained at pH 2.5, and this type of column has been used to separate acidic peptides from a wool hydrolyzate (Consden et al., 1949). More recently Stein and Moore (1949) have obtained excellent fractionations of amino acids on columns of Dowex-50 (cation exchanger, sulfonic acid groups) developed with 1.5-4 N HCl. The separations obtained are almost certainly due to differences in adsorption affinity for the resin, as well as to charge effects. At the pH used the only partially... 

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