Chloroform divinylbenzene

Purification of the activation products (PMs). The methylamine activation product dissolved in methanol is purified by chromatography, first on a column of silica gel using a mixed solvent of chloroform/ethanol, followed by reversed-phase HPLC on a column of divinylbenzene resin (such as Jordi Reversed-Phase and Hamilton PRP-1) using various solvent systems suitable for the target substance (for example, acetonitrile/water containing 0.15% acetic acid). 

Yin et al. [73,74] prepared new microgel star amphiphiles and stndied the compression behavior at the air-water interface. Particles were prepared in a two-step process. First, the gel core was synthesized by copolymerization of styrene and divinylbenzene in diox-ane using benzoylperoxide as initiator. Microgel particles 20 run in diameter were obtained. Second, the gel core was grafted with acrylic or methacryUc acid by free radical polymerization, resulting in amphiphilic polymer particles. These particles were spread from a dimethylformamide/chloroform (1 4) solution at the air-water interface. tt-A cnrves indicated low compressibility above lOmNm and collapse pressnres larger than 40 mNm With increase of the hydrophilic component, the molecnlar area of the polymer and the collapse pressure increased. 

Styrene-divinylbenzene gels are usually used for the separation of synthetic molecules dissolved in an organic solvent (Fig. 7.2). Tetrahydrofuran, a good solvent for most polymers, is frequently used as the mobile phase. However, chloroform, toluene or hot trichlorobenzene are also used to dissolve polymers that are not soluble in common solvents. 

The vinylbenzyl chloride (VBC) monomer used in this work was purchased from Aldrich (Milwaukee, WI) as an inhibited monomer mixture of the 3- and 4- isomers. The inhibitor was removed from the monomer by contact with a column of De-hibit 100 Ion Exchange Resin from Polysciences (Warrington, PA). The divinylbenzene used as a crosslinking agent was also purchased from Aldrich as an inhibited 55% solution of the isomers with 3- and 4-ethylvinylbenzene. Due to the extremely small amount of divinylbenzene used in the monomer mixtures, the inhibitor was not removed prior to polymerization. The remaining reactants and solvents include triethyl amine (99%), trimethyl phosphite (99+%), triisopropyl phosphite (95%), acetone, chloroform, and hexyl alcohol which were also purchased from Aldrich. The photoinitiator used to initiate the polymerizations was Irgacure907, donated by CibaGeigy (Hawthorne, NY). 

Fig. 15. The relation between q0 and the second virial coefficient Ae for a number of poly(methyl methacrylate) networks in various diluents (acetone, toluene, benzene and chloroform). The first number in the code refers to the concentration of methyl methacrylate in the solution before polymerization, the second to the tenfold percentage of divinylbenzene added (by volume of methyl methacrylate) [Rijke...

In this section the use of polystyrene and copolymers of styrene with various cross-linking agents as supports for solid-phase organic synthesis is discussed. Copolymers of styrene with divinylbenzene are the most common supports for solid-phase synthesis. Depending on the kind of additives used during the polymerization and on the styrene/divinylbenzene ratio, various different types of polystyrene can be prepared. However, non-cross-linked polystyrene has also been used as a support for organic synthesis [10,16-22], Linear, non-cross-linked polystyrene is soluble in organic solvents such as toluene, pyridine, ethyl acetate, THF, chloroform, or DCM, even at low temperatures, but can be selectively precipitated by the addition of methanol or water. 

Polystyrene-g-chloroformate was prepared by co-polymerizing 1% divinylbenzene with styrene, hydroxymethylating with formaldehyde, followed by treatment with phosgene. 

Stannic chloride has been attached to monomers 21 containing ester (21a), carbazole (21b), pyrrolidone (21c), nitrile (21d) and pyridine (21d) moieties. The polymeric ligands were prepared by copolymerization of styrene, divinylbenzene and functional monomers such as methyl methacrylate, A -vinylcarbazole, Af-vinylpyrrolidone, acrylonitrile and 4-vinylpyridine [33], These polymers were treated with stannic chloride in chloroform to afford the corresponding polymer-supported stannic chloride complexes (Eq. 8). These polymeric complexes have been used as catalysts for such organic reactions including esterification, acetalization, and ketal formation. These complexes had good catalytic activity in the reactions and could be reused many times without loss of activity. Their stability was much better than that of plain polystyrene-stannic chloride complex catalyst. 

Rosatzin et al. copolymerised V,W-dimethyl-V,V -bis(4-vinylphenyl)-3-oxapen-tanediamide (a metal ionophore), divinylbenzene and styrene in a chloroform solution in the presence of Ca(ll) or Mg(II) [10]. The Ca(II) ionophore resin is illustrated in Scheme 9.4. The metal ion added to the matrix mixture, was expected to act as a template for the ionophore during the polymerisation. The resulting polymers were analysed for their ability to extract ions from aqueous methanol. The polymers prepared against Ca(II) and Mg(II) were found to bind Ca(II) with 6- and 1.7-times lower dissociation constants, respectively, when... 

Apart from their behaviour as ligands in metal catalyst systems, studies of the reactivity of phosphites towards a wide variety of other substrates have attracted attention. New aspects and applications of the classical Michaelis-Arbuzov reaction and its variants continue to appear. Evidence of the thermal disproportionation of methyltriaryloxyphosphonium halides formed in the reactions of triarylphosphites with alkyl halides, together with the formation of P-O-P intermediates, has been reported. The Michaelis-Arbuzov reaction has been used in the synthesis of phosphonate-based styrene-divinylbenzene resins and polyphosphonated chelation therapy ligands.Treatment of electron-rich benzylic alcohols dissolved in triethylphosphite with one equivalent of iodine affords a low-temperature one-pot route to the related benzylic phosphonates, compounds which are otherwise difficult to prepare. Upper-rim chloromethylated thiacalix[4]arenes have also been shown to undergo phosphonation on treatment with a phosphite ester in chloroform at room temperature. The nickel(II)-catalysed reaction of aryl halides with phosphite esters in high boiling solvents, e.g., diphenyl ether, (the Tavs reaction), has also... 

Figure 6 Two-dimensional CH-correlated gel phase NMR spectrum for chloroform-swollen Boc-Cys(Acm)-OCH2-Pab-copoly (styrene 1% divinylbenzene).

A mixture of allyl phenyl disulfide (0.94 g, 5.2 mmol), divinylbenzene (mixture of m- and p-isomers 12.4 g, 95 mmol), and AIBN (0.36 g, 2.2 mmol) in chloroform (10 mL) was degassed with nitrogen for 5 min, and was polymerized by UV light irradiation for 24 h at 5 °C and for a further 3 h at 80 °C. The polymer was ground, and the particles were suspended in methanol. The S-S linkages were cleaved by the reduction with NaBH4 for 12 h. This cleavage procedure was repeated twice to complete the reaction [5],... 

Example 3.8 Preparation of artificial catalytic antibody (see Fig. 3.7) Vinylpyridine (420 mg), styrene (4.20 g), divinylbenzene (5.20 g), dibenzoylmethane (448 mg a transition-state analog), cobalt(II) acetate (498 mg), and ADVN (100 mg) were dissolved in anhydrous methanol (2.5 mL) and chloroform (6.7 mL). The resulting mixture was sonicated under vacuum and purged with N2 for 5 min at 0 °C. The polymerization was carried out at 45 °C for 24 h. The resulting polymer was ground and sieved. The polymer particles were packed into a stainless steel column and washed with methanol/acetic acid (7/3) and then with methanol to remove dibenzoylmethane and cobalt(II) acetate. 

ABEI, A-(4-aminobutyl)-N-ethylisoluminol) DSC, N,A-disuccinimidyl carbonate FITC, fluorescein isothiocyanate OG, -octylglucopyranoside FMOC, 9-fluoroenylmethyl chloroformate DOSS, dioctyl sulfosuccinate EDTA, ethylenediaminetetraacetic acid PSDVB, polystyrene-divinylbenzene copolymer DMpCD, di-methyl p-cyclodextrin SPE, solid-phase extraction LLE, liquid-liquid extraction LIF, laser-induced fluorescence. 

Definition A synthetic anion exchanged polymer in which quaternary ammonium groups are attached to a copolymer of styrene and divinylbenzene Properties Wh. to buff-colored fine powd. odorless to si. amine odor insol. in water, ethanol, chloroform, ether, benzene, org. soivs. stable to 150 C... 

There is some limitation in the choice of solvents which can be used with styrene-divinylbenzene copolymer packings. Widely used solvents are tetra-hydrofuran, chloroform, dichloromethane and toluene. Unsuitable solvents, which will shrink the column packing causing the formation of column voids, channelling, and loss of efficiency, include aliphatic hydrocarbons, lower alcohols and water. 

A survey of the literature reveals some interesting features. Technical improvements have been devised for the recovery step. A controlled separation of the chloroform phase by laminar flow of mother solution has been described (83). The use of basic macroreticular ion exchangers, such as cross-linked styrene-divinylbenzene resins, is suggested in a patent for the recovery of both rifamycin B and rifamycin S from aqueous, organic, or mixed solutions (84). A specific desorbant chloroform methanohacetic acidrwater (84 9.5 5.6 0.9) allows a 85% recovery of rifamycin B from a 0.1% chloroform solution. Direct extraction of rifamycins from fermentation broth by the use of an N-8-I4C alkyl lactim is cited in a 1986 patent (85),... 

Triethylamine (0.35 mL, 2.5 mmol) is added to a solution of p-divinylbenzene 67 (130 mg, 1 mmol), iodo monomer 66 (1 mmol), Pd(OAc)2 (9 mg, 0.04 mmol), and tri-o-tolylphosphine (69 mg, 0.2 mmol) in 5mL of DMF. The reaction mixture is heated at 100 °C for 5 h under nitrogen atmosphere and poured into 20 mL of methanol. The precipitated polymer is collected by filtration and further purified by redissolving in a minimum amount of hot chloroform and precipitating into acetone. The resulting polymer is extracted with methanol for 24 h and dried under vacuum at 40 °C for 2 days (yield 87%). 

Aso et al. [294,295] studied the radical polymerization of pure o-divinylbenzene by AIBN in benzene solution at 20 to 90 °C. The products obtained were either totally or at least partially soluble in organic solvents such as aromatic hydrocarbons or chloroform. A conversion of 70% to a totally soluble product could be reached with [Mo] = 0.6 mol/L at 70 °C. The amount of pendant double bonds in the polymers was determined by use of IR spectroscopy and bromination and found to be 30 to 90% of the maximum value calculated for one double bond per monomer unit. The authors suggested that cyclization had occurred in addition to conventional 1,2-polymerization. 

It is important to understand that solubility does not indicate the absence of interactions between the polymer and the stationary phase and insolubility of a polymer does not provide information on interaction effects with the stationary phase. Solubility refers to the binary system of polymer and solvent, while eluent strength refers to the interplay of the interactions among stationary phase, mobile phase, and polymer. As an example, chloroform is a good solvent for poly(methyl methacrylate). However, PMMA is strongly retained on a polar silica column when using chloroform as the eluent, since there is a pronounced interaction of the polar repeating units with the stationary phase. In contrast, on styrene-divinylbenzene-based columns, PMMA clearly elutes in the SEC mode before the injected solvent, indicating that no adsorption of the PMMA onto the stationary phase occurs under these conditions. 

A divinylbenzene-ethylene-styrene copolymer is sulfonated by 3.5-10% solutions of chlorosulfonic acid in organic solvents, e.g. chloroform or 1,2-dichloroethane at RT to yield cation-exchange resins. Porous st)rrene-divinyl-benzene-ethylvinylbenzene copolymers have also been treated with the reagent and hydrazine hydrate to form ion-exchange resins containing sulfonyl hydrazide groups. ... 

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