Divinylbenzene Resin Research Articles

Comparison of porosity characteristics of macroporous poly(styrene–divinylbenzene) resins determined from mercury intrusion data and image analysis of transmission electron micrographs

The porosity characteristics of a series of 12 macroporous poly(styrene–divinylbenzene) resins have been quantified by the mercury intrusion method and by image analysis of transmission electron micrographs (TEM) of resin particle cross-sections. The results from both methods correlate extremely well. Bearing in mind that the TEM procedure does ‘observe’ pores more directly than the Hg intrusion method, the present study tends to validate the intrusion procedure and calculations.

Separation of Fullerenes C60, C70, and C76-84 on Polystyrene Divinylbenzene Columns

Abstract New HPLC methods have been developed to effectively separate and recover essentially pure amounts of C60 and C70 fullerenes from the lower MW contaminants and higher MW fullerenes co-extracted from carbon soot. Separation with toluene/methylene chloride mobile phase results from different degrees of interaction of conjugated π-electrons of the fullerenes and the polystyrene divinylbenzene (PSDVB) resin stationary phase. The presence of either toluene or CS2 in the mobile phase attenuates π-electron interactions. The separation mechanism becomes predominantly size exclusion chromatography for a CS2 concentration in the mobile phase ≥ 60%. Excellent separation of C60, C70 and C76–84 is obtained with the analytical Envirosep-ABC(tm) columns in less than 15 minutes. Substituted fullerene reaction products are also well separated from their parent compounds. The effects of column size and PSDVB pore size on analytical separation, along with the effects of pore size, mobile phase, and sample size on se...

Solid phase synthesis of a tetrapeptide labelled with Carbon‐13. Preparation of L‐[U‐13C]lysyl‐L‐[1‐13C]arginyl‐L‐[3‐13C]asparyl‐L‐[1‐13C]serine

AbstractSynthesis of a [13C] tetrapeptide L‐[U‐13C]Lysyl‐L‐[1‐13C]Arginyl‐L‐[3‐13C]Aspartyl‐L‐[1‐13C] Serine (KRDS) on a p‐alkoxybenzyl ester polystyrene‐1% divinylbenzene resin support is described by using repetitive nonhydrolytic base cleavage of α‐amino protective groups in Solid Phase Peptide Synthesis (SPPS). Protected [13C] amino acid (AA) used in this SPPS model were prepared with 9‐Fluorenylmethyloxycarbonyl (Fmoc) protecting group and with different acid labile side chain protecting group over AA type as: Fmoc‐Ser(tert‐Bu)‐OH, Fmoc‐Asp(tert‐Bu)‐OH, Fmoc‐Arg(Pmc)‐OH and Fmoc‐Lys(Fmoc)‐OH. All the protected AA were coupled by N,N′‐dicyclohexyl carbodiimide (DCC) procedure, followed by Fmoc group cleavage using 20% piperidine in N,N dimethylacetamide (DMA). Quantitative deblocking side‐chain AA protection and removal of KRDS from the solid support was effected by treatment with 50% trifluoroacetic acid in methylene chloride in a one pot‐procedure. Homogeneous free [13C] KRDS was obtained in 90% overall yield after HPLC purification. This synthesis schedule offered the advantage over present solid phase method which used acidolysis for repetitive α‐amino group deblocking.

Adsorption of Nonionic Surfactants on Synthetic Adsorbents

The adsorption of polyethoxylated monyl-phenol on macroreticular styrene divinylbenzene copolymers from aqueous solutions was investigated. Styrene divinylbenzene resins show a high adsorption affinity for non-ionic surfactants and prove to be very suitable as adsorbents for these. Addition of both electrolytes and methanol decreases the amount of surfactant adsorbed. The adsorption on a carboxylic acid resin increases with decreasing pH value

Isothiocyanato‐substituted hydrophilic polymer beads for immobilization of enzymes

AbstractStyrene–glycidylmethacrylate–divinylbenzene resin beads could be converted to highly hydrophilic resin beads by acid treatment. These resin beads could be modified with isothiocyanato (NCS) groups quite easily using a Friedel–Crafts reaction and a subsequent nucleophilic reaction with KSCN. The resin beads substituted with NCS groups were useful as supports to immobilize enzymes, because they were not only hydrophilic but also bind proteins covalently. The enzymes immobilized onto the resin beads showed sufficiently high catalytic activities for a long period.

The extraction of uranium from nitrate solutions using a resin containing tributyl phosphate

Tributyl phosphate adsorbed on to the macroporous polystyrene divinyl benzene resin, Levextrel OC 1023, was used for the extraction of uranium from solutions of nitric acid and aluminium nitrate with a total nitrate concentration of 5.5 M. Uranium is strongly adsorbed from these solutions; the distribution coefficient increases with the concentration of aluminium nitrate. The equilibrium distribution is described by the Langmuir equation. The rate of adsorption of uranium was correlated by the conventional equation for mass transfer through the liquid film below 0.1 g U/L in solution. However, at higher values this was no longer valid and a modified version of this equation is proposed here which correlated all adsorption runs up to 1 g U/L. Uranium is readily stripped from Levextrel resin with water. The kinetics of this process are controlled by particle diffusion and can be described by the simplified equation proposed by Vermeulen. Values of diffusivity of uranium in Levextrel resin were lower than in water but very significantly higher than in conventional ion exchange resins.

Macroporous gel-type styrene-divinylbenzene materials

The title materials are produced from macroporous styrene (St)-divinylbenzene (DVB) resins prepared in the presence of a polymer solution as a porogen; the resulting beads are functionalized upon grafting St-Vinylbenzylchloride (VBC) copolymers through post-copolymerization with residual double bonds. The resulting material has been quaternized by trimethylamine at 35° C. The rate constant of that reaction is then about 6 times higher than that observed for a similar resin (same Cl content and same porous morphology) prepared by direct terpolymerization of St, DVB and VBC.

Catalytic Activity of Sulphonated Styrene—Divinylbenzene Resins

The evolution of the catalytic activity of sulphonated styrene—divinylbenzene resins was studied in the vapour-phase esterification of acetic acid with ethanol. The activity of fresh resins decreases during the initial period when the reactants are first introduced into the reactor. Also, a variation is observed in the global activation energy and in the Arrhenius pre-exponential factor during this period. After that period (ca. 2 h), the activity reaches a stable value, which remains constant during the experiment and in successive runs. Once the resins have been used, and after a long stoppage, the activity decreases. After a 2-month stoppage, the activity decreases by 30%. This variation affects only the pre-exponential factor and not the activation energy. The different activity levels observed and the evolution can be related to a change in the nature of catalytic sites. Before the addition of reactants to a fresh resin, sulphonic groups inside the resin are associated, whereas after the passage of reactants these sulphonic groups dissociate. A mathematical model has been developed to explain this evolution.

Selective adsorption of plant products

The results from this study demonstrate that neutral resins can selectively concentrate specific indole alkaloids from dilute aqueous mixtures. Adsorption was observed to provide a one to two order of magnitude improvement in concentrating these alkaloids, as compared to an equivalent single-staged extraction. Since the sorption correlates with the concentration of the neutral form of the dissolved alkaloid, the adsorption is dependent on both the pH of the medium and the pKa of the alkaloids. Also, adsorption is dependent on specific sorbent-sorbate characteristics. In this study, by exploiting differences in the acid-base properties and the sorption characteristics of specific indole alkaloids, separation factors of 20-30 were observed. Although this behavior is valuable for analytical separations, the present study considers the application to the primary recovery of alkaloids from plant cell processes. Throughout this study it was also observed that the polycarboxylic ester resin (XAD-7) behaved quite differently from the styrene divinylbenzene resin (XAD-4). Despite a lower capacity, the XAD-7 resin was considerably more selective in adsorbing indole alkaloids than the XAD-4 resin. These alkaloids could also be desorbed from the XAD-7 resin by acidifying the liquid, while organic solvents were required to desorb these compounds from the XAD-4 resin.

Simultaneous synthesis of sequence-unrelated peptides derived from proteins of human papillomaviruses

Amino acid sequences derived from the early (E) and late (L) coding regions of human papillomaviruses (HPV) type 6, 11, and 16 were analysed by means of a computer program for prediction of B-cell determinants. Eight peptides ranging from 9 to 17 amino acids and containing potential B-cell determinants were selected for synthesis. The peptides were synthesized by using a configuration for solid-phase synthesis that enables the simultaneous synthesis of several peptides in flow reactors at low pressure on standard poly(styrene-1% divinylbenzene)resin. Crude peptides were obtained in good yield and purity. They were then further purified by high-performance liquid chromatography for use as solid antigens in site-directed serology.

Polymer-supported analogues of t-butyl hypohalites. Preparation and applications in synthetic organic chemistry

Crosslinked polymer-supported analogues of t-butyl hypochlorite and t-butyl hypobromite were prepared and developed as a new class of recyclable solid-phase oxidizing and halogenating reagents. The preparation of these new reagents involved a three-step polymer-analogous reaction starting from styrene-divinylbenzene crosslinked polymer. A ketone functional group was introduced into the copolystyrene-2% divinylbenzene resin beads by a Friedel-Crafts reaction with bromoacetone. This functional group was then converted to a tertiary alcoholic function on the polymer support by a Grignard reaction with methylmagnesium iodide. The treatment of this tertiary alcohol resin with sodium hypochlorite or sodium hypobromite yielded the polymeric t-butyl hypochlorite or hypobromite. These hypohalites were estimated iodometrically. These reagents were found to oxidize primary and secondary alcohols to the corresponding carbonyl compounds in high yields. They were also found to be suitable for halogenation of carbonyl compounds and amides. The spent polymeric reagent after the oxidation or halogenation step can be easily removed by filtration and can be regenerated many times by treating with the sodium hypohalite without any loss of capacity.

Solvatochromic solvent polarity measurements and selectivity in reversed-phase liquid chromatogrphy

The E T(30) polarity values of binary acetonitrile—water and methanol—water mobile phases, used in reversed-phase liquid chromatography, were measured and compared with methylene selectivity (α CH 2 for both traditional siliceous bonded phases and for a polystyrene—divinylbenzene resin reversed-phase material. The variation in methylene selectivity for both was found to correlate best with percent organic solvent in methanol—water mixtures, while the E T(30) polarity provided the best correlation in acetonitrile—water mixtures. The polymeric resin column was found to provide higher methylene selectivity than the siliceous bonded phase at all concentrations of organic solvent.

Analysis of the Pore Structure of Ion-Exchange Resins and the Adsorption Equilibrium of Fe3 /Cl- Complex Ions

Abstract The microstructure of ion-exchange resins has been investigated to understand more clearly the ion-exchange mechanism. Nine types of resins with different pore structures were used: all of the polystyrene family crosslinked with divinylbenzene and anionic resins, with mesh sizes ranging from 100 to 200, except for one (20–50 mesh). Various pore volumes of each resin were determined by measurements of intrusion of some chemical species (H2O, Nd3+, and Hg) into the resin. The results are analyzed on the basis that an ion-exchange resin particle consists of four regions. They are: 1) the mercury intrusion region, 2) the region where coions (such as Nd3+) can intrude but mercury cannot, 3) the region where water or counterions can intrude but coions cannot, and 4) the polymer matrix region occupied by the polymer skeleton. The former two regions are not influenced by the resin-fixed ionic groups. While it used to be thought that specific adsorption of counterions may occur in the entire exchange resi...

Development of capillary gas chromatographic—mass spectrometric methodology for the simultaneous determination of ibuprofen and [ar- 2H 4]ibuprofen in serum: demonstration of kinetic equivalence in the beagle

A capillary gas chromatographic—mass spectrometric method for the determination of ibuprofen and tetra-deuterated ibuprofen in serum is described. Ibuprofen, [ar- 2H 4]-ibuprofen and the internal standard, [ar- 2H 4,3,3,3- 2H 3]ibuprofen, are extracted (after acidification) from serum onto a cross-linked styrene divinyl benzene resin by an automated sample processor. After elution and evaporation of the organic phase, samples are reconstituted with solvent and analyzed without derivatization by capillary gas chromatography—mass spectrometry. This methodology was used to evaluate possible kinetic isotope effects after the coadministration of an equimolar mixture of ibuprofen and the deuterium-labeled covariant in the beagle. No significant differences in absorption or elimination were observed.

Synthesis and biological activity of some new leucine-enkephalin analogues

The opioid pentapeptide leucine-enkephalinamide and eleven of its analogues have been synthesised by the solid phase technique employing mostly 9-fluoroenylmethyloxycarbonyl amino acid active esters in the presence of 1-hydroxybenzotriazole. Both the conventional chloromethylated copolystyrene-2% divinylbenzene resin as well asp-alkoxybenzyl alcohol resin were employed and it was observed that yields were uniformly better with the latter resin. The analogues were made by affecting single or multiple replacements of amino acids involving positions 1,2 and 5. Some of the analogues were found to be more potent than morphine in the guinea pig ileum assay.

Quantitative secondary ion monitoring gas chromatography/mass spectrometry of diethylstilbestrol in bovine liver.

A procedure is described for the extraction of diethylstilbestrol (DES) from animal tissue for quantitative capillary gas chromatography/mass spectrometry (GC/MS). The procedure is based upon use of a strong anion exchange polystyrene divinylbenzene resin for sample purification. The recovery of DES from the resin clean up was 88% in the high parts per trillion (ppt) range. Criteria for identification of DES using selected ion monitoring (SIM) GC/MS are presented. Liquid chromatography/mass spectrometry (LC/MS) was used to investigate altered DES cis/trans ratios observed in biological extracts.

Sorption of unsaturated monocarboxylic acids on anionexchange resins and non-ionic resins from aqueous solutions

An increasing number of carbon atoms in unsaturated carboxylic acids gave rise to increased distribution coefficients in sulphate and acetate solution, both on styrene—divinylbenzene resins and on anion-exchange resins. On the non-ionic resins the double bond led to a large decrease in the retention volume, which was less to 2-alkenoic acids than for isomers with double bond more distant from the carboxylic acid group. The results indicate that hydrophobic interactions had a larger effect than π-bond interactions with the aromatic resin. For the anion exchangers, hydrogen bonding explains the higher retention of 2-alkenoic than alkanoic acids. The carboxylate ions derived from 2-alkenoic acids exhibited a higher ion-exchange affinity than those from alkonoic acids. This can be related to the greater acid strength of the parent acid.

STABLE ISOLATED SYMMETRICAL ANHYDRIDES OF Nα‐9‐FLUORENYLMETHYLOXYCARBONYLAMINO ACIDS IN SOLID‐PHASE PEPTIDE SYNTHESIS:

The synthesis and isolation of symmetrical anhydrides of N alpha-9-fluorenylmethyloxycarbonyl (Fmoc) amino acids using water soluble carbodiimide is described. These compounds were used in a solid phase peptide synthesis of methionine-enkephalin on a p-benzyloxybenzyl ester polystyrene 1% divinylbenzene resin support. Homogeneous free pentapeptide was obtained in 42% overall yield. The Fmoc amino acid symmetrical anhydrides were stable during prolonged storage (2 years of 0 degrees) and offer advantages over present "Fmoc solid phase" methods which use anhydrides formed in situ.

Removal of allergens from natural oils by selective binding to polymer supports. II. Application of aminated resins to isoalantolactone and costus oil

A number of crosslinked polymers containing primary or secondary amine functional groups were prepared by chemical modification of styrene–divinylbenzene or styrene–acrylonitrile–divinylbenzene resins. The polymers were tested in the binding of α-methylene-γ-butyrolactone allergens via Michael addition of their nucleophilic ends with the conjugated system of the lactones. Best results were obtained using 1% crosslinked poly(aminoethylstyrene) in ethanol; polymers with higher crosslinking or other functional groups were somewhat less reactive. This technique for the removal of α,β-unsaturated lactones from solution was applied successfully to the selective removal of the allergenic components of costus oil, a natural oil of plant origin used in the cosmetics industry. After purification of the costus extracts, the allergens which were retained by the polymer could be cleaved by permethylation followed by base treatment, and characterized. The polymer-treated natural oil had lost its allergenic properties while the polymer-retained materials were found to be powerful allergens.

Heterogenization of homogeneous catalysts — The immobilization of transition metal complexes on ion-exchange resins

Immobilized homogeneous catalysts can be prepared by the sequential addition of a bifunctional ligand followed by a metal complex onto an ion-exchange resin. Several rhodium, cobalt and platinum/tin complexes were anchored onto a macroreticular sulfonated styrene—divinylbenzene resin in this manner. These materials exhibit olefin hydroformylation activity, and extremely low metal leach characteristics.