Strong/weak anion exchange

Strong Base Anion Exchangers. As ia the synthesis of weak base anion exchangers, strong base resias are manufactured from styrenic as well as acryhc copolymers. Those based on copolymers of styrene and divinylben2ene are chloromethylated and then aminated. These reactions are the same as for the styrenic weakbase resias. The esseatial differeace is the amine used for amination. Trimethyl amine [75-50-3] N(CH2)3, and /V, /V- dim ethyl eth a n ol amine [108-01 -0] (CH2)2NCH2CH20H, are most commonly used. Both form quaternary ammonium functional groups similar to (8). 

Fig. 1. Demineializei systems consist of various unit processes arranged to meet the system needs. I Lstrong acid cation exchanger I I Strong ha anion exchanger 0 Degasifier I Mixed bed I Weak acid cation exchanger 1 1 Weak base anion exchanger and I IConnterflow cation.

The symbol R3N represents the complex weakly basic anion-exchanger radical. The symbol R,N represents the complex strongly basic anion-exchanger radical. 

To complete the deionization process, water from the cation unit is passed through a strong base anion exchange resin in the hydroxide form. The resin exchanges hydrogen ions for both highly ionized mineral ions and the more weakly ionized carbonic and silicic acids according to1,2 ... 

NP, WP, P = non polar, weakly polar, polar, respectively SCX, SAX, WAX = strong cation, strong anion, weak anion exchanger, respectively. 

Kulprathipanja, S. (2007) Separahon of dtric add from gluconic add in fermentafron broth using a weakly or strongly basic anionic exchange resin adsorbent. U.S. Patent 7,241,918 Bl. 

Separation and purification chromatography has to be applied before the quantitative chromatography. Some purification techniques applied are lEC, such as DEAE-Sephadex A-25 [571], weak anion-exchange column [572,573], strong anion-exchange column (564), cation-exchange column... 

Acrylic strong base anion exchangers (9) are synthesized from acrylic weak base resins. The tertiary amine groups are converted to a quaternary ammonium functionality by reaction of chloromethane [74-87-3], CH3C1, and the weak base resin. 

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