Dowex 50 resin column

To prevent during the denitration step the formation of precipitates on which Pu and Am were partially and irreversibly adsorbed, denitration and oxalate precipitation were carried out in a single step by addition of the waste solution to the formic and oxalic acid mixture, the latter acid acting as a metal complexant during the denitration step. By experimental tests performed on simulated HAW according to this modified process scheme, separation yields of about 99.5% for Pu and 99.8% for Am were measured. A further reduction of the actinide content was reached by flowing the clarified HAW solution through a Dowex 50 resin column. The oxalate precipitation experiments on fully active HAW solutions have practically been completed. The results obtained from five runs (Table IV) confirmed the previous results obtained on simulated solutions. 

Fig. 13.1 Elution of homologous trivalent actinides and lanthanides from a Dowex 50 resin column at ZTC with a-hydroxyisobutyrate as eluant. The broken curve for element 103 (Lr) is a prediction.

The elution profile of praseodymium chloride (PrCIs) by a citrate buffer at pH = 3 from a Dowex 50 resin column (originally studied by Mayer and Tompkins (1947)) can be described by equation (7.1.102a) (Lightfoot etal. (1962) have described it in detail) in the presence of cerium (CeCIs) the sorption equilibria are linear and noninterfering. 

Disodium succinate [150-90-3] M 162.1. Crystd twice from water (1.2mL/g) and dried at 125°. Freed from other metal ions by passage of a 0. IM soln through a column of Dowex resin A-1 (Na form). 

S-Acetylthiocholine chloride [6050-81-3] M 197,7, m 172-173° The chloride can be purified in the same way as the bromide, and it can be prepared from the iodide. A few milligrams dissolved in H2O can be purified by applying onto a Dowex-1 CL resin column (prepared by washing with N HCl followed by COf— free H2O until the pH is 5.8). After equilibration for lOmin elution is started with CO3—free distilled H2O and... 

S-Acetylthiocholine chloride [6050-81-3] M 197.7, m 172-173" The chloride can be purified in the same way as the bromide, and it can be prepared from the iodide. A few milligrams dissolved in H2O can be purified by applying onto a Dowex-1 Cf resin column (prepared by washing with N HCl followed by CO3— free H2O until the pH is 5.8). After equilibration for lOmin elution is started with CO3 —free distilled H2O and 3ml fractions are collected and their OD at 229nm measured. The fractions with appreciable absorption are pooled and lyophilised at 0-5°. Note that at higher temps decomposition of the ester is appreciable hydrolysis is appreciable at pH >10.5/20°. The residue is dried in vacuo over P2O5, checked for traces of iodine (cone H2SO4 and heat, violet vapours are released), and recrystd from propan-l-ol. [Clinica Chim Acta 2 316 1957],... 

Such an Ion exchange separation can also be done by us-lng a Dowex-1 anion exchange resin column In the carbonate form at pH of about 6. The Cs elutes In the first 3 ml. The column Is then washed with 3 ml HsO. 

In those esses where complete Identification la desirable, rttre earth separations, are made using a cation exchange resin column (Dowex-50, citrate elution at pi 3.5) and elevated temperature as described by Thompson et al., as follows ... 

After dilution to about 0.3 V BC1, the aoln. le slowly passed through Dowex-1 resin column (200 mesh-), which Is bested to the boiling point of Isopropyl alcohol (82.3 0) (I9l). This results In a very effective separation of Pb end Bl, the Bl adhering strongly to the realn. 

It 1b possible to partially separate the Fr from Cs by passing a 1 H HHO3 soln. through a short resin columns of colloidal Dowex-50, the Fr coming off at the last of the other alkali elements. 

The Au foil Is quickly dissolved In aqua regia and the Au extracted with ethyl acetate for 1 min. The aqueous phase is then eluted through a Dowex-1 anion resin column (2 zmn diameter, 1 cm long) with 6 M HC1 to complete the removal of Au end other impurities. The dropB. containing the actinide fraction are evaporated and the activity is then eluted through a Dowex-50 resin cation column with 0.4 M soln. of ammonium Q -hydroxy-isobutyrate, which is adjusted to pH 4.0 with HH4OH to separate the various actinide elements from each other, (Mv-Fm-E-Cf)... 

Prepare two columns, one containing Sephadex and the other Dowex resins, by forming a slurry of the resin in water which is then poured into the empty column. Allow the resin to settle, and wash well with water prior to use.c... 

Prepare the ion-exchange column (i) introduce a small piece of glass wool above the stopcock (ii) add the slurry of Dowex resin (150 g) and water (300 mL) (iii) exchange the Cl of the commercial resin to OH by treatment of the resin with 200 mL of 10% NaOH aqueous solution and (iv) wash the resin with water until the eluent is neutral (pH indicator strip). 

To regenerate the Dowex resin after use, place in a glass column, wash with... 

The synthesis of this substance, starting with methyl 2-acetamido-4,6-0-benzylidene-2-deoxy-a-D-glucoside, was performed as follows. The two isomers which were formed were separated on a Dowex 50 colunm, and one (Md +109°) was shown to be identical with natural muramic acid. The strong dextrorotation effectively ruled out the L-glucosamine configuration, and the configuration of the lactic moiety was deduced to be most likely d. The second isomer had [ ] +52° and differed, in its behavior on resin columns and in paper chromatography, from natural muramic acid. 

Fig. 2. Pressure drop across ion exchange resin columns as a function of flow rate for resins of different particle size. Operating conditions 40°C column, 0.62 X 100 ora, stainless steel resin, Dowex 1 X —8.

The lyophilisate was tlien dissolved in a 1 1 mixture of ethanol water and eluted over an ion exchange resin column (DOWEX 2IK Ch form). 

Procedure Pass 10 ml of urine through a cation-exchange resin column (Dowex 60-W-X4, 20-50 mesh, in the hydrogen form) and wash the column with 30 ml of distilled water. Elute the amino acids with 20 ml of concentrated ammonia solution. Evaporate this eluate to dryness in vacuo. To the residue add 1 ml of trifluoroacetic anhydride and 0.5 ml of trifluoroacetic acid, and allow the mixture to stand at room temperature for 20 minutes. Remove excess reagents with a stream of air and treat the oily residue with an ethereal solution of distilled diazomethane (DANGER Poisonous-explosive) for 15 minutes. Remove excess diazomethane (CAUTION ) with a stream of air. Dissolve the residue in methanol and inject a suitable aliquot part into the gas chromatograph. Figures 25 and 26 show results obtained by this procedure. 

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