Polystyrene divinylbenzene copolymer resins

Bonds et al. reported the preparation of polystyrene divinylbenzene copolymer resin supporting titanocene TiCp2Cl2. The catalyst efficiency is greater than a corresponding nonattached species [89]. 

A macroporous polystyrene-divinylbenzene copolymer is produced by a suspension polymerization of a mixture of monomers in the presence of water as a precipitant. This is substantially immiscible with the monomer mixture but is solubilized with a monomer mixture by micelle-forming mechanisms in the presence of the surfactant sodium bis(2-ethylhexylsulfosuccinate) (22). The porosity of percentage void volume of macroporous resin particles is related to percentage weight of the composite (50% precipitant, 50% solvent) in the monomer mixture. 

N-oxide salts (HBTU and TBTU, respectively) [39], or from l-hydroxy-7-azabenzotriazole (HOAt) such as N-[(dimethylamino)-lH-l,2,3-triazolo[4,5-fe] pyridino-l-y]methylene]-N-methy]methanaminium tetrafluoroborate N-oxide (HATU) [40], are well established reagents. They are especially devoted to peptide coupling reactions due to their efficiency and the low degree of undesirable race-mization produced in the final peptide compared to the use of classical carbodi-imide-coupling methods. Therefore, as the polystyrene-supported HOBt is an often used polymeric reagent (Section 7.6.3) [41], its transformation in a supported HOBt and tetramethylurea-derived aminium salt analog to HBTU and TBTU resulted directly. Thus, the reaction of polystyrene-2% divinylbenzene copolymer resin P-HOBt (20) with tetramethylchloroformamidinium tetrafluoroborate (21) (4 equivalents) in the presence of triethylamine gave polymeric N-[(lH-benzotriazol-l-yl)(dimethylamino)methylene]-N-methylmethanaminium tetrafluoroborate N-oxide (P-TBTU, 22) (Scheme 7.6) [42],... 

Polymer-supported triphenylphosphine ditriflate (37) has been prepared by treatment of polymer bound (polystyrene-2% divinylbenzene copolymer resin) triphenylphosphine oxide (36) with triflic anhydride in dichloromethane, the structure being confirmed by gel-phase 31P NMR [54, 55] (Scheme 7.12). This reagent is effective in various dehydration reactions such as ester (from primary and secondary alcohols) and amide formation in the presence of diisopropylethylamine as base, the polymer-supported triphenylphosphine oxide being recovered after the coupling reaction and reused. Interestingly, with amide formation, the reactive acyloxyphosphonium salt was preformed by addition of the carboxylic acid to 37 prior to addition of the corresponding amine. This order of addition ensured that the amine did not react competitively with 37 to form the unreactive polymer-sup-ported aminophosphonium triflate. 

Type II rhamnogalacturonan is present in wine as a dimer (dRG-II-B). It may be isolated by adsorption chromatography on a polystyrene and divinylbenzene copolymer resin column (Pellerin et al., 1997). The average RG-II concentrations in white wines are between 20 and 60 mg/1, while those of red wines range from 100 to 160 mg/1. 

SPE has been extensively used to analyse grape and wine volatiles, either in the form of resin cartridges or even in hand-prepared bed columns. The most used sorbents are Cis bonded phases, polystyrene/divinylbenzene copolymers and hydrophobic cross-linked polystyrene copolymer resins imder the commercial names Bond Elut C18, Discovery DSC-18, Strata C18, Lichrolut RP-18, Lichrolut EN, Chromabond easy. Strata SDB-L and Amberlite XAD-2, among others. 

A large variety of polymers has been considered. In the beginning, polystyrene and styrene/ divinylbenzene copolymers (Merrifield resins) were by far the most used.73 Then others were tested such as polyvinyls,47-50,61-64 polyacrylates,72 4,75 and cellulose.76,77 Most commonly, diphenylphos-phane groups were grafted on the polymeric support, either directly or via one CH2 group. 

Polystyrene divinylbenzene Ion-exchange resins are commonly manufactured from a copolymer of styrene (Figure 4.8) and divinylbenzene (Figure 4.9). The divinylbenzene content in the matrix determines the degree of cross-linking. So, 5% mol divinylbenzene... 

NaHC03 (0.2 g) was added to a suspension of chloromethylated polystyrene-1 % divinylbenzene copolymer (Merrifield resin, 0.5 g, 0.76 mmol/g) in DMSO (3 mL). After stirring for 7 h at 155 °C, the resin was washed successively with H20, MeOH, DMF, CH2C12, and Et20 and then dried under reduced pressure. To confirm the conversion of the chloromethyl resin into the aldehyde resin, two analyses were used FTIR analysis showing the typical carbonyl absorption at 1700.5 cm-1 and microanalysis showing the absence of any chlorine on the resin. The benzaldehyde resin (1.0g, 0.59mmol/g) was suspended in... 

In the reaction vessel of a Beckman 990 Peptide Synthesizer was placed 0.8 g (0.8 mmol) of benzhydrylamino-polystyrene-divinylbenzene resin (Lab Systems, Inc.) as described by Rivaille, supra. Amino acids were added sequentially to this resin by means of the usual methods of Boc-strategy of peptide synthesis on above copolymer. 

The polypeptide product was simultaneously removed from the resin and completely deprotected by treatment with anhydrous liquid HF. A mixture of 2.0 g of protected polypeptide resin and 2 mL of anisole (scavenger) in a Kel-F reaction vessel was treated with 20 mL of redistilled (from CoF3) anhydrous liquid HF at 0°C for 30 minutes. The HF was evaporated under vacuum and the residue of (pyro)-Glu-His-Trp-Ser-Tyr-3-(2-naphthyl)-D-alanyl-Leu-Arg-Pro-Gly-NH2,as its HF salt, was washed with ether. The residue was then extracted with glacial acetic acid. The acetic acid extract was lyophilized to yield 0.8 g of crude material. The crude polypeptide was loaded on a 4x40 cm. Amberlite XAD-4 column (polystyrene-4% divinylbenzene copolymer) and eluted with a concave gradient from water (0.5 L) to ethanol (1 L). The tubes containing fractions from effluent volume 690 mL to 1,470 mL were pooled and stripped to dryness to yield 490 mg of partially purified polypeptide. 

Figure 3.18 Commercially available resins (A) polystyrene-divinylbenzene (B), (C) polymethacrylate-based copolymers. (Reprinted from Ref. 16 with permission.)...

Currently, the most widely used adsorbents in RPC are silica resins, containing a hydrophobic phase, usually octyl (C8), octyldecyl (C18), methyl (Cl), or phenyl groups. Additionally, new adsorbents based on organic materials such as methacrylate, polystyrene, and copolymers of styrene and divinylbenzene have been developed (Hearn, 1998). 

Aluminum chloride and its derivatives are the most familiar Lewis acids and are routinely employed in many Lewis acid-promoted synthetic transformations. The first polymer-supported metal Lewis acids to be studied were polymers attached by weak chemical or physical interactions to a Lewis acid. In the 1970s Neckers and coworkers reported the use of styrene-divinylbenzene copolymer-supported AlCl,- or BF3 as catalyst in condensations, esterifications, and acetalization of alcohols [11,12]. This type of polymer-supported AICI3 (1) is readily prepared by impregnation of a polystyrene resin with AICI3 in a suitable solvent. Subsequent removal of the solvent leaves a tightly bound complex of the resin and AICI3. The hydrophobic nature of polystyrene protects the moisture-sensitive Lewis acid from hydrolysis, and in this form the Lewis acid is considerably less sensitive to deactivation by hydrolysis. This polymer complex could be used as a mild Lewis acid catalyst for condensation of relatively acid-sensitive dicyclopropylcarbinol to an ether (Eq. 1) [13],... 

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. 

Different methods of solid-phase extraction (SPE) of wine volatiles were developed by using Amberlite XAD-2 polystyrenic resins (Gunata et al., 1985 Versini et al., 1988), reverse-phases Ci8 (Williams, 1982 Gianotti and Di Stefano, 1991 Di Stefano, 1991 Zulema et al., 2004 Ferreira et al., 2004), and more recently, highly cross-linked hydroxyl-ated polystyrenic phases (e.g., ENV+, Ferreira et al., 2004 Boido et al., 2003) and highly cross-linked ethylvinylbenzene-divinylbenzene copolymers (e.g., LiChrolut EN, Lopez et al., 2002 Ferreira et al., 2004 Genovese et al., 2005) stationary phases. 

Polystyrene-divinylbenzene cross-linked copolymer adsorbent resins removed effectively both limonin and naringin from citrus juices (44). Over 85% of limonin was adsorbed from about 50 bed volume juices of grapefruit, navel orange, lemon and tangerine. Up to 70% of naringin was also removed from grapefruit juice. 

M. Negre, M. Bartholin and A. Guyot, Autocross-linked isoporous polystyrene resins, Angew. Makromol. Chem., 1979, 80, 19-30 J. Hradil and E. Kralova, Styrene-divinylbenzene copolymers post-cross-linked with tetrachloromethane, Polym., 1998, 39, 6041-6048 S. Belfer and R. Glozman, Anion exchange resins prepared from polystyrene cross-linked via a Friedel-Craft reaction, J. Appl. Polym. Sci., 1979, 24, 2147-2157. 

Preparation of the resin Polystyrene-divinylbenzene (1%) copolymer 21 (Fluka) was washed [71] to removed shorter polystyrene components and remaining monomers and reagents with each of the following solutions at 60-80°C for 30-60 min NaOH (1 N), HCl (1 N), NaOH (2 N)-dioxane (1 2), HCl (2 N)-dioxane (1 20, water, dimethyl formamide (DMF). The resin was then washed at room temperature with HCl (2 N) in methanol, water, methanol, methanol-dichloromethane (1 3), and methanol-dichlo-romethane (1 10) and the resin was dried at 50-70°C under reduced pressure. The washed polystyrene resin (13 g) was suspended under nitrogen in anhydrous cyclohexane (80 mL) in a 250-mL polymer synthesis flask. Tetra-methylethylenediamine (TMEDA, 20 mL, 132.5 mmol) and n-butyllithium (2.0 M in cyclohexane, 80 mL, 160 mmol) were successively added and the mixture was stirred at 65°C for 4 h. The dark burgundy-colored resin was filtered under nitrogen and washed with anhydrous cyclohexane (2 X 100... 

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