Chloromethylated polystyrene properties

Owing to this type of reaction, both chloromethylated polystyrene and poly(oc-methylstyrene) show crosslinking properties. 

Table 8.2 Properties of initial polystyrene (PS), chloromethylated polystyrene (CMPS), and intramolecularly hypercrosslinked polystyrenes (IHPSs), based on the latter...

The synthesis of cu-amino-substituted 18-crown-6 and [2.2.2]cryptand readily bonded with chloromethylated polystyrene cross-linked by different amounts of DVB, is described [86]. Such bonded polyesters are used as interfacial transfer catalysts promoted by anions. As in the case of analogous soluble systems, the catalytic activity of cryptands is higher than that of crown ethers and quaternary onium salts. Because of their high chemical stability, such catalysts can be regenerated without chemical decomposition. However, the impairment of mechanical properties caused by comminution of the polymer matrix remains to be solved. 

The effect of the chemical properties of a support on the activity of dispersed zero-valent metals has been shown [27]. Chloromethylated polystyrene, cross-linked with 4-7% DVB with high porosity and surface area (0.1 -0.03 pm particles), was functionalized by the following groups rr-donor and 7r-acceptor groups capable of forming molecular associates with the substrate hydrophobic and hydrophilic groups... 

As the functional sites introduced in this way are located in positions which even in the shrunken state of the support are easily accessible, this type of chloromethylated polystyrene exhibits excellent properties for further transformations in the Merrifield peptide synthesis. Nevertheless, we should retain that this type of reactive polymer may only contain its chloromethyl functions in a relatively dense filling in the shell zone of the polystyrene particles. 

The application of the nucleophilic properties oS Bender s salts to the displacement of reactive halides on polymer substrates has been thoroughly evaluated by Daly and Lee (72). Polymers containing halomethyl hinctional groups such as chloromethylated polystyrene, poly(epichlorohydrin), copoly(epichlorohydrin-ethylene oxide), poly(2,6-feis-bromomethylphenylene oxi ) and poly vinyl chloride) were utilized as substrates with varying degrees of success. 

Aromatic electrophilic substitution is used commercially to produce styrene polymers with ion-exchange properties by the incorporation of sulfonic acid or quaternary ammonium groups [Brydson, 1999 Lucas et al., 1980 Miller et al., 1963]. Crosslinked styrene-divinyl-benzene copolymers are used as the starting polymer to obtain insoluble final products, usually in the form of beads and also membranes. The use of polystyrene itself would yield soluble ion-exchange products. An anion-exchange product is obtained by chloromethylation followed by reaction with a tertiary amine (Eq. 9-38) while sulfonation yields a cation-exchange product (Eq. 9-39) ... 

We are interested in the application of polymers as adsorbents, ion exchangers, fuel cells, and permeable materials. In this regard, the first resins with some of these properties were obtained by D Aleleio in 1944 based on the copolymerization of styrene and divinylbenzene. Unfunctionalized polystyrene resins cross-linked with divinylbenzene (Amberlite) are widely applied as adsorbents [191,192], In addition, the polystyrene-divinylbenzene resins functionalized with sulfuric acid (sulfonation) to create negatively charged sulfonic sites are applied as cation exchangers, and treated by chloromethylation followed by animation produce anionic resins [193,194],... 

Chen and Janda (288, 289) recently reported the use of non-cross-Unked polystyrene (NCPS) (290) as a soluble support with complementary solubility properties with respect to PEG resins. The synthesis of a complex prostaglandin structure 8.106 (291) using the chloromethyl NCPS support 8.102, the acid-labile THP linker, and the three synthons 8.103 (291), 8.104 (292), and 8.105 (293) is shown in Fig. 8.48. 

Hacroporous-type crossllnked chloromethylated or lodomethylated polystyrene was used to initiate the polymerization of monomer 1. The product poly(styrene-g-phenyltrlmethylenphosphlne oxide) jU, is a white bead-like resin (n-4.1-10.5), fdilch showed efficient chelating properties toward heavy metal ions such as UOo , Th " ",... 

Positive interactions between cationic species, including protons, with aromatic structures comprise an intensively examined and already well-documented phenomenon [142, 143], In the hypercrosslinked polystyrene these interactions may well be enhanced by a possible presence of condensed aromatic systems. As was shown in Chapter 6, Section 4.4, anthracene-type structures may easily be formed by the condensation of two chloromethylated styrene repeating units, followed by a subsequent oxidation. However, the early elution of pure HCl in Fig. 12.1 does not imply any retentive interactions between protons and the polymer. The retention of HCl occurs only in the presence of a salt. But why would the properties of HCl in the polymeric phase change so dramatically in the presence of metal chlorides, while no association of HCl with LiCl or CaCl2 takes place in solution The version (i) of attractive interactions of protons with the polystyrene phase thus cannot be accepted without serious doubt. 

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