Cation exchange resins Amberlite

The hydrolysis of sucrose catalyzed by the strongly acidic cation-exchange resin Amberlite 200C in RH form was chosen as a model reaction to compare the use of stirred tank and continuous-flow reactors [47-49], Scheme 10.6. 

A number of minor components present in commercial neomycin have been separated by column chromatography on a carboxylic cation-exchange resin, Amberlite CG-50 99. The components were eluted from the resin with ammonium hydroxide solution. T.L.C. of the eluent fractions showed the presence of two previously unreported impurities which were then isolated on Dowex 1X2 and tentatively identified using NMR and mass spectrometry. 

PREPARATION OF CATION-EXCHANGE RESIN. Amberlite CG-120-H cation-exchange resin is placed in a 600 cm3 beaker about 3 g of dry resin (10-meq capacity) is required for each 0.9 x 15 cm column. The resin is covered with 3N NH4OH, swirled for 30-60 min, and allowed to settle. The NH OH is decanted off, and the process is repeated twice. The resin is then washed with doubly distilled water until it is approximately neutral. 

The reaction mixture is heated at 80°C for 5 min to cease the reaction, followed by centrifugation. The supernatant is run onto a column of 100 parts by volume of cation-exchange resin [Amberlite IRC-50, NH4+-form]. The column is washed with water, and then eluted with 1 N-aqueous ammonia to give fractions which contain kanamycin B-3 -phosphate. The fractions are collected and concentrated under reduced pressure, and then the concentrate is run onto a column of 100 parts by volume of cation-exchange resin [carboxy-methyl Sephadex C-25, NH4+-form]. The column is washed with water, and eluted with 0.2 N-aqueous ammonia to give fractions which contain kanamycin B-3 -phosphate. The fractions are collected, concentrated and lyophilized, whereby 4.5 parts of kanamycin B-3 -phosphate. 

In 40 parts by volume of water is dissolved 0.6 part of 2, 3 -epimino-2 -deamino-3 -deoxykanamycin B, and in the presence of 9 parts by volume of Raney nickel the mixture is stirred while introducing hydrogen gas at a pressure of 100 kg/cm2 at 60°C for 6 h. After the reaction Raney nickel is separated by filtration. The Raney nickel is washed well with 300 parts by volume of 1 N-aqueous ammonia and the washing is added to the filtrate. The whole is concentrated to about 100 parts by volume. The precipitated insolubles are removed by filtration, and the pH of the supernatant is adjusted to about 5.0 with hydrochloric acid. The mixture is run onto a column of 50 ml of cation-exchange resin [Amberlite CG-50, NH4+-form]. 

Cation-Exchange Resin. Amberlite 15 resin was prepared in the manner described for the anion resin except that the acid-base washing sequences were reversed. 

Polacrilin potassium 2-10 Cation exchange resin (Amberlite IRP88 )... 

S. Ivanov, R. Boeva, S. Tanielyan, Catalytic epoxidation of propylene with tert-butyl hydroperoxide in the presence of modified carboxy cation-exchange resin "Amberlite" IRC-50, J. Catal. 56 (1979) 150. 

Acidic resins [1, 514, after citation of ref. 17]. The biogenetically patterned cyclization of polyenes by Lewis acid catalysts can also be effected by cation-exchange resins (Amberlite IR-20 and XE-100).17a Thus methyl trans.trans-iarntsate (1) is cyclized by XE-100 in acetic acid to (2), (3), and (4), separable by gas chroma-... 

The carbohydrates present a fragile structure so that the removal of the aqueous solution by evaporation on vacuum degrades the molecules. However, at the end of the oxidation process, the electrolyte is easily neutralized with a cation-exchange resin (Amberlite 200), which allows a lyophilization of the aqueous solution free from inorganic species. 

The electrolytic solution was neutralized with a cation-exchange resin (Amberlite 200 from Sigma). The aqueous solution, free from inorganic ions, was then lyophilized, and the crystals obtained were trimethylsilylated for analysis on GC/MS ... 

This estimation is close to the experimental value (Qdes = 19.7 C). This means that the electrooxidation of sucrose took place at 0.74 V versus RHE with nearly no poisoning species involved. The sole quantity of electricity, which served to oxidize sucrose, was thus Qox. At the end of electrolysis, this value was estimated to ca. 104 C, and the yield of the sucrose transformation was estimated close to 60%. The solution was sampled and neutralized on a cation-exchange resin (Amberlite 200, Sigma). The solutions obtained, free from inorganic cations (Na+), were chromatographed again to assure the reproducibility of the last analysis. 

The ion-exchange chromatography was first applied to the separation of geometrical isomers of a cobalt(III) complex by King and Walters who separated tram- and cw-[Co(N02)2(NH3)4]. From the cation-exchange resin (Amberlite IR-120), 1 mol/ dm NaCl eluteJ the fra/w-isomer and then the c -isomer was eluted with 3 mol/dm NaCl. This difference was attributed to that the m-isomer was more firmly held because of its larger dipole moment. 

All FIA atomic absorption methodologies developed for indirect AA determination involve the utilization of flame atomic absorption spectrometry (FAAS) as detector, and are based on oxidation of AA to DHAA and reduction of a metallic specie (Fe(III) to Fe(II), Cr(VI) to Cr(III), Mn(VII) to Mn(II) and Mn(IV) to Mn(II)). Most of the methods apply a microcolumn with a solid phase (polymeric adsorbent Amberlite XAD4 [136], cation-exchange resin Amberlite IR120 [137,138], or poly(aminophosphonic acid) chelating resin [139,140]) to retain the reduced metallic species. The other possibility is the utilization of a solid-phase reactor filled with the substance to be reduced. Thus, Noroozifar et al. [141] propose a reactor filled with Mn02 suspended on silica gel beads. 

Thorin indicator solution, dissolve 25 mg of Thorin in 5 ml of distilled water. Methylene blue indicator solution, dissolve 15 mg of methylene blue in 50 ml of water. Cation exchange resin, Amberlite IR-120 (H). 

One hundred mg per kg body weight of DPA was administered to male Wistar albino rats weighing about 250 g. Twenty-four hour urine specimens were collected, acidified to pH 1.0 with 6 N-HCl and extracted three times with ethyl acetate and twice with ethyl ether. The combined extracts were trimethylsilylated with bistrimethylsilylacetamide or methylated with dimethylformamide dimethylacetal and subjected to GLC and/or GC-MS as described previously (3). The remaining water-layer was applied to cation exchange resin. Amberlite IR-120 column. The neutral and acidic amino acids were eluted by IM-pyrimidine and the basic amino acids by 2N-ammonium hydroxide. The eluates were concentrated separately under vacuo and analyzed by GLC and/or GC-MS after derivatization to the dimethyl ami nomethylene methyl ester with dimethylformamide dimethylacetal respectively (5). 

The general procedure was outlined as follows. 8.0 g compound (III) (25.0 mmol) dissolved in 100 mL of methanol was added with an excess of activated acidic styrene cation exchange resin (amberlite lR-120, Aladdin). The mixture was stirred for 4 h at room temperature. After the resin was filtrated, the solvent was removed by evaporation. The crude product was purified by column chromatography to give a pale-yellow oil 7.1 g (89 %). 

---