Amberlite nitration

Exhausted liquid ion exchangers may be regenerated in an analogous manner to ion exchange resins, e.g. Amberlite LA.l saturated with nitrate ions can be converted to the chloride form by treatment with excess sodium chloride solution. 

Several improved methods for the nitration of alkyl halides have been reported. For example, the use of KN02 in the presence of lS-crown-694 or nitrite ion bounded to macroporous quaternary ammonium amberlite resin (amberlite IRA 900) improves the yield of nitro compounds (Eq. 2.49) 95... 

Removal of inorganic interferences, particularly the removal of bromide interference in seawater by fivefold dilution of the sample, the removal of nitrate by addition of sulfamic acid, and the removal of metals by passage through Amberlite IR 120 cation exchange resin. 

Plastic film membranes can also contain fixed ion-exchange groups. Jyo and coworkers [79] chloromethylated Amberlite XAD-2 (cross-linked styrene-divinylbenzene copolymer of the macroreticular type) and formed quaternary ammonium groups in the product by treatment with dimethyltetradecylamine. They converted the substance into the chloride, nitrate or perchlorate form and saturated it with nitrobenzene. The presence of hydrophobic ion-exchange sites... 

A 90 x 6 cm column was packed with 2 kg of granular Amberlite IRA-410 resin in the chloride form (a vinylpyridine/divinylbenzene copolymer quaternized with dimethyl sulfate and converted to chloride) and washed with 3 kg of a 10% aqueous solution of sodium cyanate. This changed the resin from the chloride to the cyanate form. Sodium chloride and excess sodium cyanate were then washed from the column with distilled water until the effluent failed to give a white precipitate with silver nitrate. The reaction of equation (2) was conducted by elutriating the column with a solution of 105 grams (1.5 mols) of hydroxylamine hydrochloride in 400 ml water at about 15°C. 

Davenport and Johnson [30] used ion exchange chromatography on Amberlite IRA-900 strongly basic resin to determine nitrate and nitrite in water. 0.10M perchloric acid was used as eluent and an electrochemical cadmium electrode detector was used. 

Gel-type ion exchangers are much less resistant to osmotic shock than macroporous ones. For example, after the application of 70 cycles of osmotic shock (by treating sulfonic acid resins alternatively with 76% HNOg and wastewater from an ammonium nitrate processing plant), the number of cracked beads in the case of a gel-type resin (Wofatit KPS) was 78.3%, but for macroporous resins the number varied from only 1.2% (Amberlite 200) to 7.6% (Duolite C26) [24]. Similar results have been obtained for anion exchangers. Thus, the number of the... 

Regeneration of Amberlite-200 Resin. The Amberlite-200 resin was operated in the sodium form during the exchange cycle strontium and calcium ions replace sodium ions. In the regeneration cycle, high concentrations of sodium ion must be used to displace the strontium and calcium. Sodium nitrate was used to regenerate laboratory columns... 

Three comii rcially available longaliphatic amines, Primene JM-T (primary), Amberlite LA-2 (secondary), and trilaurylamine (TLA, tertiary), were tested as membrane carriers for nitrate, pertechnetate and chromate anions. Long-chain aliphatic amines, dissolved in an (H ic diluents, are known to extract acids according to the reaction... 

The results show that the two modules were very effective in reducing the U(VI) and Tc(VII) concentrations by about three and two orders of magnitude, respectively. The limited success with NO3 is due to the fact that these tests were performed befwe the final choice of the best carrier for nitrates was made. The use of a 0.2 M Amberlite LA-II solution as liquid membrane in the second module would have led to much better results for the removal of nitrates. 

A chromogenic crown ether (AA -bis-(2-hydroxy-5-nitrobenzyl)4,13-diazadibenzo-18-crown-6) in a mixed micellar medium was proposed for the determination of Cd in water (the detection limit was 6 ppb) [1]. The preconcentration of Cd on a chelating resin prepared by coupling Pyrocatechol Violet to Amberlite XAD-2 was studied [2]. Quantitative adsorption was achieved at pH 5-7. Nitric acid (4 M) was used as elluent. The effects of various anions (fluoride, chloride, nitrate, sulfate and phosphate) on the adsorption of Cd (Zn, Pb(Il) and Ni) were investigated. 

Amberlite 252 ion-exchanger resin in the hydrogen form. The hi was removed by the resin and the displaced formed hydrogen carbonate. The CO2 was then driven off by heating. They found traces of F, and N02" in their product although at least 85% of the original was in the nitrate form. This source was used by Stout (16) in his... 

Cortina et al. [6,18,32] studied the efficiency of impregnated resins containing the active component of Cyanex 272 adsorbed onto Amberlite XAD2 for the extraction of Zn(II), Cu(II), and Cd(II) from dilute solutions in nitrate and chloride media. The metal distribution studies show, as described in Sect. III.B, that the extraction of these metal ions involves reactions similar to those in solvent extraction systems. The extraction results indicate that Zn(Il) is adsorbed more selectively than Cu(II) and Cd(II), making possible the quantitative separation of Zn(II) from the other two [6], No significant differences were found on comparison of the extraction efficiency of these resins with Levextrel 807 84 resins [35]. 

Similar studies of application of anion exchangers Amberlite IRA-900 (macroporous, polystyrene, strongly basic anion exchanger of type 1, 16-50 mesh) [133-135] and Amberlite IRA-410 (gel, polystyrene, strongly basic of type 2,16-50 mesh) [135] for recovery and removal of trace amounts of Pd(II), Pt(II), Ru(III), Rh(III), Au(III) and Ir(IV) ions from chloride and radioactive nitrate waste waters were carried out by the Els et al. [133, 134] and El-Said et al. 

Kameo et ai. reported [50] the use of polystyrenesulfonic acid as a catalyst in the nitration of aromatics with HNO3. Nitration of toluene with 90% HNO3 over dried sulfonated polystyrene resin (Rohm and Haas amberlite IR-120) was also reported by Wright et al. at 65-70°C to give an ortho para isomer ratio of only 0.68, much lower than usual ortho-para ratios in acid-catalyzed nitrations [11]. It is considered that the nitroniura ion is strongly ion paired to the resinsulfonic acid. The ion-pair salt thus formed is much bulkier than the free nitronium ion or such nitronium salts as NO2 BF4. 

A process has been developed by Ayres for the purification of zirconium, in which the various impurities are absorbed upon a cation-exchange resin. The zirconium itself is not absorbed as it is in the colloidal condition. This state is not difficult to achieve with, for example, zirconyl nitrate ZrO(NOs)2, since it is normally hydrolysed to the highly insoluble hydrated oxide in a neutral or near neutral solution. A zirconium ore is therefore broken in concentrated sulphuric acid and the soluble zirconium sulphate converted to the nitrate by suitable means and passed through a column of resin in the usual manner. Amberlite I.R.-100 has been used, in the hydrogen form. Impurities such as iron, beryllium and rare earth elements are absorbed completely, together with about 80 per cent of the titanium. The resin capacity for zirconium, however, is as low as 0-84 mmoles/100 cm of resin, and it is therefore recovered virtually completely in the pure column effluent. The very small amount of zirconium taken up by the resin is probably retained by a surface absorption process rather than true ion-exchange. The zirconium can be precipitated by alkah from the effluent as the hydrated oxide, in massive form, for conversion to other compounds and finally to metal. The resin is regenerated for further use by elution of the cation impurities with, for example, dilute sulphuric acid. 

Fermentation broth containing cephamycins A and B was acidified at harvest to obtain maximum stability of the antibiotics. The broth was filtered, and 4000 liters of filtrate containing about 80 pg cephamycin/ml was passed through a 380-liter bed of Amberlite XAD-2 (Rohm and Haas). The resin bed was washed with water and then eluted with 60% aqueous methanol. The rich eluate, 800 liters, was concentrated under reduced pressure to 160 liters and adjusted to pH 3.5 with aqueous ammonia. This procedure gave 40% yield of 2% purity. One half of this concentrate was diluted to 120 liters and absorbed on a 22.5-liter bed of Amberlite IRA-68 resin in the chloride cycle. The activity was recovered by elution with 200 liters of a pH 7.5 solution of I M sodium nitrate and 0.1 M sodium acetate. The eluate was adjusted to pH 3 and adsorbed on a 45-liter bed of Amberlite XAD-2 resin to separate the product from salts. The column was washed with water, eluted with 320 liters of 25% aqueous acetone and then concentrated under reduced pressure to 17.4 liters. The concentrate was adjusted to pH 4.0 with aqueous ammonia and freeze-dried. The yield was 620 g of cephamycin, about 13% pure, for a calculated recovery of 125%. 

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