Styrene anion exchange resin

Scheme 2.4 Addition polymerization synthesis of styrenic anion exchange resins...

The second step of the 7-aminocephalosporanic acid (7-ACA) process is the deamidation of glutaryl-7-ACA (Fig. 19-22), the first step is described in Sect. 19.3.2.2. 7-ACA is an intermediate for semi-synthetic cephalosporins. Hoechst Marion Roussel uses the glutaryl amidase immobilized on a spherical carrier. Toyo Jozo and Asahi Chemical immobilize the glutaryl amidase on porous styrene anion exchange resin with subsequent cross-linking with 1% glutardialdehyde. The catalyst is applied in a fixed bed reactor in a repetitive batch mode (70 cycles). Here, an enzymatic process has replaced an existing chemical process for environmental reasons (Fig. 19-23) ... 

Ion-exchange separations can also be made by the use of a polymer with exchangeable anions in this case, the lanthanide or actinide elements must be initially present as complex ions (11,12). The anion-exchange resins Dowex-1 (a copolymer of styrene and divinylben2ene with quaternary ammonium groups) and Amherlite IRA-400 (a quaternary ammonium polystyrene) have been used successfully. The order of elution is often the reverse of that from cationic-exchange resins. 

Epoxy resin (Tufnol, Bakelite, Epophen) Styrene divinylbenzene ion exchange resins Reillex HPQ anion exchange resin Phenol/formaldehyde cation exchange resin Polyurethane Cellulose (as tissues)... 

Elemental composition P 38.73%, H 1.26%, O 60.01%. The compound may be identified by physical properties alone. It may be distinguished from ortho and pyrophosphates by its reaction with a neutral silver nitrate solution. Metaphosphate forms a white crystalline precipitate with AgNOs, while P04 produces a yellow precipitate and P20 yields a white gelatinous precipitate. Alternatively, metaphosphate solution acidified with acetic acid forms a white precipitate when treated with a solution of albumen. The other two phosphate ions do not respond to this test. A cold dilute aqueous solution may be analyzed for HPO3 by ion chromatography using a styrene divinylbenzene-based low-capacity anion-exchange resin. 

Such oxometal catalysts can also be immobilized as anions on anion exchange resins as reported recently by Kurusu and Masuyama51 who used tetrabromo-oxomolybdate(V) bound to a tetraalkylammonium-containing styrene/divinylbenzene copolymer as a catalyst for the epoxidation of olefins and oxidation of alcohols with TBHP. 

Weak Base Anion Exchangers. Both styrenic and acrylic copolymers can be converted to weak base anion-exchange resins, but different synthetic routes are necessary. Styrene—DVB copolymers are chloromethylated and aminated in a two-step process. Chloromethyl groups are attached to the aromatic rings (5) by reaction of chloromethyl methyl ether [107-30-2], CH3OCH2Cl, with the copolymer in the presence of a Friedel-Crafts catalyst such as aluminum chloride [7446-70-0], A1C13, iron(III) chloride [7705-08-0]9 FeCl3, or zinc chloride [7646-85-7], ZnC. ... 

The data presented lead to the general conclusion that Dowex anion-exchange resins (types 1x8 50-400, 1x4 50-400, and 1x2 100-400 styrene-... 

Ion-exchange polymeric resins are the most important types of exchangers currently in use [113-123], The first, totally organic ion-exchange resin was synthesized in 1935 by Adams and Holmer, when they produced a phenol-formaldehyde cation-exchange resin and an amine-formaldehyde anion-exchange resin, both obtained with the help of condensation polymerization reactions [113], In 1944, D Alelio synthesized styrene-based polymeric resins, which could be modified to obtain both cationic- and anionic-exchange resins. The majority of the resins commercially applied currently are of this type, for example, Amberlite IR-20, Lewatit S-100, Permutit Q, Duolite, C-20, Dowex-50, and Nalcite HCR. 

These TLC plates have cation- or anion-exchange resins bonded to their surfaces. The resins are materials such as styrene-divinylbenzene copolymers having either quaternary ammonium or sulphonic acid groupings for ion exchange. They are particularly usefril for substmices of high molecular weight and for amphoteric materials. Strong acids or alkalis are usually used as mobile phases. 

It was predicted, and subsequently confirmed, that an anion exchange resin based upon an acrylic matrix should demonstrate beneficial exchange equilibria and kinetics towards large organic ions compared with the styrenic structures. A simplistic explanation for this lies with the greater hydrophilic nature of the aliphatic skeletal structure of the acrylic matrix, which in turn means a weaker van der Waals type attraction between the resin matrix and the hydrocarbon structure of an organic counter-ion. 

In the ion exchange process the leach liquor is passed through a bed of anion exchange resin beads which are loaded with chloride or in some cases nitrate. The resin will normally be a polymer carrying quaternary amine functions and having the generalized formula Pol(NR3)x+Cl, where Pol represents a polymer chain such as styrene-divinylbenzene copolymer, R = alkyl and... 

Colestyramine Anion exchanger The chloride of a strongly basic anion-exchange resin containing quaternary ammonium groups attached to styrene-divinylbenzene copolymer ... 

Subsequently D Alello developed the polystyrene-hased resin in 1944 (4). Two years later, polystyrene anion-exchange resins made hy chloromethylation and amination of the matrix were produced. Four principal classes of ion-exchange resins were commercially availahle by the 1950s. These are the strong-acid, strong-hase, and weak-hase resins derived from styrene-divinylbenzene copolymers, and the weak-acid resins derived from cross-linked acrylics. To this day, the most widely used ion exchangers are synthetic organic polymer resins based on styrene- or acrylic-acid-type monomers as described by D Alelio in U.S. Patent 2,3666,007. 

Comparisons of commonly used XAD resins have been published for the isolation of both fulvic acid (Aiken et al., 1979) and humic acid (Cheng, 1977) from water. These resins differ in pore size, surface area, polymer composition, and polarity (Table 5) (Kunin, 1977). As with anion-exchange resins, hydrophobic styrene-divinylbenzene resins (XAD-1, XAD-2, XAD-4) were found more difficult to elute than hydrophilic acrylic-ester resins (Table 6). This is due to hydrophobic interactions, and possible tt-tt interactions with the aromatic resin matrix of styrene-divinylbenzene resins. In addition, ki-... 

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