Duolite

Amberlite and Duolite are trade names of Rohm Haas resins. 

Duolite C-433 4.5 1.19 Acrylic-DVB type very high capacity. Used for metals removal and neutralization of alkaline solutions. 

Duolite C-464 3.0 1.13 Polyacrylic resin with high capacity and outstanding resistance to osmotic shock. 

Duolite A-7 2.2 1.12 Phenolic type resin. High porosity and hydrophilic matrix. pH range is 0 to 6. 

Type Duolite International Ltd Rohm Haas Co., USA Dow Chemical Co., USA Bio-Rad Labs Ltd, Watford, UK... 

Strong acid cation exchangers Duolite C225 Duolite C255 Duolite C26C Amberlite 120 Amberlite 200 Dowex 50 AG50W AGMP-50 ... 

Weak acid cation exchangers Duolite C433 Duolite C464 Amberlite 84 Amberlite 50 Bio-Rex 70 ... 

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

Weak base anion exchangers Duolite A303 Duolite A378 Amberlite 45 Amberlite 68 Amberlite 93 AG3-X4A... 

Chelating resins Duolite ES466 Amberlite 718 Chelex 100... 

Strongly acidic cation exchangers (polystyrene sulphonic acid resins). These resins (Duolite C225, Amberlite 120, etc.) are usually marketed in the sodium form and to convert them into the hydrogen form (which, it may be noted, are also available commercially) the following procedure may be used. 

Strongly basic anion exchangers (polystyrene quaternary ammonium resins). These resins (Duolite A113, Amberlite 400, etc.) are usually supplied in the chloride form. For conversion into the hydroxide form, treatment with 1M sodium hydroxide is employed, the volume used depending upon the extent of conversion desired two bed volumes are satisfactory for most purposes. The rinsing of the resin free from alkali should be done with de-ionised water free from carbon dioxide to avoid converting the resin into the carbonate form about 2 litres of such water will suffice for 100 g of resin. An increase in volume of about 20 per cent occurs in the conversion of the resin from the chloride to the hydroxide form. 

A 50 mL or 100 mL burette, with Pyrex glass-wool plug or sintered-glass disc at the lower end, can generally be used for the determinations described below alternatively, the column with side arm (Fig. 7.4a) is equally convenient in practice for student use. Reference will be made to the Duolite resins the equivalent Amberlite or other resin (see Table 7.1 in Section 7.1) may of course be used. 

Anion exchange resin. Proceed as in the previous experiment using 1.0 g, accurately weighed, of the air-dried strongly basic anion exchanger (e.g. Duolite A113, chloride form). Fill the 250 mL separatory funnel with ca 0.25M sodium nitrate solution, and allow this solution to drop into the column at the rate of about 2 mL per minute. Collect the effluent in a 500 mL conical flask, and titrate with standard 0.1M silver nitrate using potassium chromate as indicator. 

Procedure. Prepare a column of the anion exchange resin using about 15 g of Duolite Al 13 in the chloride form (Section 7.9). The column should be made up in 2 M hydrochloric acid. 

Procedure. Prepare an anion exchange column (Section 7.8) using about 40g of Duolite A113 (chloride form). The ion exchange tube may be 16 cm long and about 12 mm internal diameter. Wash the column with 0.6M sodium nitrate until the effluent contains no chloride ion (silver nitrate test) and then wash with 50 mL of 0.3 M sodium nitrate. 

Theory. Cadmium and zinc form negatively charged chloro-complexes which are absorbed by a strongly basic anion exchange resin, such as Duolite A113. The maximum absorption of cadmium and zinc is obtained in 0.12 M hydrochloric acid containing 100 g of sodium chloride per litre. The zinc is eluted quantitatively by a 2M sodium hydroxide solution containing 20 g of sodium chloride per litre, while the cadmium is retained on the resin. Finally, the cadmium is eluted... 

Tetra-n-butylammonium hydroxide (0.1 M solution in methanol). Prepare an anion exchange column using an anion exchange resin such as Duolite A113 or Amberlite IRA-400, convert to the hydroxide form and after washing with water, pass 300-400 mL of methanol through the column to remove water (see Section 7.2). 

Of industrial importance at present is die biotransformation of fumarate to L-aspartic add by Escherichia cdi aspartase. Modified versions have been developed, such as the continuous production of L-aspartic add using duolite-ADS-aspartase. A conversion higher than 99% during 3 months on a production scale has been achieved. 

Chelating CHjCOOH -CH2N ch2cooh H+ 4-14 Dil. H2SO+, HC1 Dowex XF-4195, Dowex XF-4196, Duolite ES-63, Duolite CS-346... 

Series, No. 107, Nijhoff, Dordrecht, 1986, pp. 119-1451. Constant Separation-Factor Treatment If the valences of all species are equal, the separation factor atJ applies, where atJ = KtJ= Z (16-46) cjn/ FIG. 16-8 Ideal mass-action equilibrium for three-component ion exchange with unequal valences. K AC = 8.06 K B C = 3.87. Duolite C-20 polystyrenesul-fonate resin, with Ca as A, Mg as B, and Na as C. [Klein et al., Ind. Eng. Chem. Fund., 6, 339 (1967) reprinted with permission.]... 

Among the microbial pectinesterases, the one from Coniothyrium diplodiella56 was purified by repeated chromatography on columns of Duolite A-2 and DEAE-cellulose. Two electrophoretically homogeneous forms of pectinesterase were obtained, having an identical pH optimum and the same behavior towards pectins of different d.e. 

The pectinesterase produced by Sclerotinia libertiana78 was purified on columns of Duolite A-2, Amberlite CG-50, and CM-cellulose. The final product was purified 266-fold, its sedimentation coefficient was calculated to be 4.41 S, and zone electrophoresis in starch gel showed a slight contamination of this product. 

The only pectic enzyme thus far obtained in crystalline form is the endo-D-galacturonanase from Acrocylindrium.209 Crystallization of the enzyme from a solution of ammonium sulfate was preceded by chromatography on calcium phosphate, Duolite CS 101, and DEAE-cellulose, and by starch-gel electrophoresis. 

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