Substituted divinyl benzene

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) ... 

Bimetallic complexes, such as RuPt(CO)5(PPh3)3, have been immobilized on phosphinated poly(styrene-divinyl-benzene) by a similar hgand-substitution reaction (equation 10). The resulting supported bimetallic complexes have been characterized by IR spectroscopy and are found to act as ethylene Hydrogenation catalysts. 

No.caf.Dmethphan Antitussives, Separation on porous polymer Styrene-divinyl benzene 500x5 expectorants, resins methyl methacrylate co- or antihistaminics polymer, substituted 500x3 various others with hydroxymethyl groups Me0H-NH.0H(99 1) MeOH-H2D-NH4OH(95 5 l) 59... 

Other o-nitrophenol-containing resins have been prepared with the aim of increasing the distance between the reactive center and the macromolecular backbone, which should accelerate the active ester formation by achieving an easier approach of the reagents. Thus, the Friedel-Crafts alkylation of styrene-divinyl-benzene copolymer with 4-hydroxy-3-nitrobenzyl chloride promoted by aluminium trichloride gave 4-hydroxy-3-nitrobenzylated polystyrene (70) (approximately 30% of the aromatic rings of the polymer were substituted according to elemental... 

Two types of methathesis polymerization have been used to make PAVs. Thorn-Csanyi and coworkers have used transition-metal-mediated metathesis of divinyl-benzenes to make alkyl- and alkoxy-substituted PPVs, but the products are primarily oligomers [53,54]. 

Nakagawa and co-workers [18] used techniques based on high resolution Py-GC and Py-GC and TGA to measure thermal degradation of chloromethyl substituted polystyrene. A typical TGA weight loss curve is shown in Figure 4.1. Degradation starts at 200 "C and peaks at 400 °C. Typical pyrolysis products of chloromethylated styrene-divinyl benzene (St-DVB) copolymers are the monomers, dimers and trimers of styrene, p-methyl styrene, and divinyl and ethyl styrene. For styrene chloromethyl St-DVB copolymers, in addition to the above, /-methyl styrene monomer and m- and p-chloromethyl styrene monomers are also present in pyrolysates. 

This book has been divided into three areas chemical detection, biological detection, and decontamination. The subject matter in the chapters include cross-linked divinyl benzene-substituted methacrylate polymers (Chapter 2), porous silicon (Chapter 3), reactive glass surfaces (Chapter 4), polycarbosilanes (Chapter 5), non-aqueous, chemically cross-linked polybutadiene gels (Chapter 6), conducting polyaniline nanofibers (Chapter 7), organically doped polystyrene and polyvinyltoluene (Chapter 8), electroplated polymer cast resins (Chapter 9), self assembled monolayers (Chapter 10), amphiphilic functionalized norbomene polymers (Chapter 11), transition metal substituted polyoxometalates (POMs) (Chapter 12), cross-linked divinyl-benzamide phospholipids (Chapter 13), and silica and organo silyl polymers (Chapter 14). 

METATHESIS POLYCONDENSATION OF SUBSTITUTED p-DIVINYL-BENZENES A WAY TO EASILY PROCESSABLE /i-PHENYLENEVINYLENE (PV) OLIGOMERS WITH VALUABLE PROPERTIES... 

The number of nitrogens in the chain can vary from two on up. In many cases the nitrogen-carbon bond is an integral part of the polymer network. There are more than two carbons between nitrogens in some cases, and the carbons may carry other substitutions. The actual ionogenic functionality is a mixture of primary, secondary and tertiary amines. Polyamine resins made by condensing phenol, formaldehyde and polyamine were among the first commercial resins. Other methods of manufacture include the reaction of a polyamine with a chloromethylated styrene-divinyl-benzene copolymer, and condensation of epichlorhydrin with ammonia or polyamines. 

Finally, an example will be discussed in which a polymer support is uniformly functionalized by copolymerization of suitable monomers. As already mentioned in the beginning of this section, the monomers of polystyrene based supports — styrene and divinyl-benzene — are not very suitable for functionalization prior to the copolymerization, since the reactivity of vinyl aromates is simply not compatible with reaction conditions required to functionalize the benzene ring by substitution reactions. 

Typical nonreactive macroporous polymeric supports based on polystyrene-divinyl-benzene were substituted by reactive polymeric supports including polyvinylpiride (PVP) and weak or strong ion exchange resins. All these new types of polymeric supports for SIR are characterized by the presence of either acid or base groups. The selection of a suitable reactive polymeric support should be controlled by the following rules. 

Depending on the mechanism, chelation reactions can be considered as additions or substitutions (for instance ion is replaced by one or several ions The amino resins derived from the copolymers of styrene, chlorostyrene and divinyl benzene can be modified by halogenoacetic acid to form structures which are able to complex metal ions (reaction 12). Kaeriyama and Shimura prepared polystyrenes (6) substituted by ethylenediaminetetraacetic acid, which are able to absorb heavy metal ions from solutions. 

The polymer support used in these reactions should have a reasonably high degree of substitution of reactive sites. In addition, it should be easy to handle and must not undergo mechanical degradation. There are several polymers in use, but the most common one is the styrene-divinyl benzene copolymer. 

Addition of acyl anion equivalents (propenal d reagents) to ketones provides general access to a -hy-droxy enones. In an application of this method to pentaimulation, the trimethylsilyl- or ethoxyethyl-pro-tected cyanohydrins of a, -enals were used." The derived tertiary acetates undergo elimination (p-TsOH/benzene) to the divinyl ketones which cyclize in the acidic reaction medium (equation 25)." In some cases the a -hydroxy or a -silyloxy enones underwent cyclization but in much lower yields. Substitution in the ring and on the double bonds is compatible. 

Analogous decarbonylations have been observed for ketones under ultraviolet irradiation at elevated temperatures. From a preparative point of view the behavior of diphenyl-substituted and a,a-divinyl-substituted ketones is interesting, as they are decarbonylated when their benzene solutions are subjected to ultraviolet irradiation.69 This favorable effect of phenyl sub-stitutents on decarbonylation has been noted also for cyclic ketones for example, under suitable conditions l-phenyl-2-indanone eliminates carbon monoxide and yields 90% of 5,6,ll,12-tetrahydro-5,6-diphenyldibenzo[a,e]-cyclooctene as a mixture of cis- and trans-forms,10 whereas 2-indanone itself is hardly decarbonylated at all in benzene solution. That in other cases decarbonylation is usually more profitable in the gas than in the liquid phase is shown by studies of the photolysis of tetramethyl-l,3-cyclobutanedione which in the gas phase gives 2 equivalents of carbon monoxide and a quantitative yield of 2,3-dimethyl-2-butene.71... 

Clive and coworkers have recently disclosed a method for the general synthesis of para-disubstituted benzenes, represented by 34, which involved conversion of 1,4-diketones 31 into the corresponding divinyl derivatives 32 after reaction with vinyUithium [19]. Subsequent RCM of these dienes afforded compounds 33, which was then followed by aromatization to afford the substituted benzenes 34 (Scheme 17.5). Substituted aromatics 35 and 36, two of the nine examples described in the paper, were synthesized in good yields from their respective diketone precursors. 

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