Divinylbenzene Resin Research Articles

Novel polymer-supported β-dithioketonate nickel catalysts for selective propylene dimerization

Brominated and chloromethylated styrene–divinylbenzene resins were used for the synthesis of polymer-bound dithio-β-diketones, obtained by anchoring the chelate ligand through the central position. The heterogenized dithio-β-diketone ligand was subsequently reacted either as sodium salt with a Ni(II) phosphino derivative or directly with a Ni(0) complex in the presence of a free phosphine and activated in situ with an aluminum co-catalyst for the selective dimerization of propylene to 2,3-dimethylbutenes. The hetetogenized catalysts so obtained showed, particulary when prepared starting from chloromethylated styrene/divinylbenzene resins, very high activity and selectivity towards 2,3-dimethylbutenes. Moreover, the above catalysts, at least under the adopted reaction conditions, did not display any appreciable metal leaching during the catalytic cycle, thus working as really heterogeneous systems. Copyright © 1999 John Wiley & Sons, Ltd.

High-performance chelation ion chromatography of transition and heavy metal ions on polystyrene–divinylbenzene resin dynamically modified with 4-chlorodipicolinic acid

A neutral polystyrene–divinylbenzene column, combined with 4-chlorodipicolinic acid present in the mobile phase, has been developed as a chromatographic system for the high efficiency isocratic separation of transition and heavy metal ions. Retention arises from the formation of a stable dynamically coated chelating stationary phase, the capacity of which is dependent upon both the pH and ligand concentration in the eluent. The results obtained illustrate the increased loading and selectivity of this chlorinated chelating molecule in comparison with unsubstituted dipicolinic acid, exemplified by the separation of 7 metals in under 8 min. The column also displayed a strong affinity for CdII and an unusual retention for NiII, which showed a good symmetrical peak shape.

Sorbitol-modified poly(N-glycidyl styrene sulfonamide) for removal of boron

A sorbitol-containing resinous polymer has been prepared starting from crosslinked polystyrene-10% divinylbenzene (DVB) resin beads (720-840 mm) by the following series of reactions: (1) chlorosulfonation, (2) sulfonamidation with N-propyl- amine, (3) condensation of sulfonamide with epichlorohydrin, and (4) modification with sorbitol. The resulting sorbitol-modified polymer has been demonstrated to be an efficient and regenerable specific sorbent for removal of boron in parts per million (ppm) levels. Kinetics of boron sorption and regeneration of the polymer were investigated. q 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 2113-2119, 1998

Determination of aryloxyphenoxypropionic acid herbicides in water using different solid-phase extraction procedures and liquid chromatography–diode array detection

For isolation and trace enrichment of aryloxyphenoxypropionic acid (ArPP) herbicides from drinking, spring, and ground water a sensitive, robust method is presented. A 1–2 l volume of aqueous samples was passed through a disposable solid-phase extraction cartridge, packed with 500 mg of Carbograph-1 at a flow-rate of 100 ml/min. After washing, ArPPs are selectively eluted with 8 ml of dichloromethane–methanol (80:20, v/v) with 50 mmol/l formic acid and evaporated to dryness. The mixture was reconstituted with 250 μl of water–acetonitrile (75:25, v/v) acidified with 0.1% trifluoroacetic acid and 100 μl was injected into the high-performance liquid chromatography system. The ArPPs were separated via a binary gradient of water and a mixture of methanol–acetonitrile. Detection and confirmation were performed by diode array detection. Recovery of the six acid herbicides ranged between 90% and 98%. The limits of detection of ArPPs were 7–20 ng/l for drinking water and 16–36 ng/l for spring water. In terms of recovery and selectivity the effectiveness of Carbograph-1 cartridges was compared with that of LiChrolut-EN cartridges and polystyrene–divinylbenzene Empore disks. Relevant parameters such as pH and flow-rate for solid-phase extraction with divinylbenzene resins were optimized.

Effect of polystyrene–divinylbenzene resin sulfonation on solute retention in high-performance liquid chromatography

Polystyrene–divinylbenzene (PS–DVB) resins were sulfonated under different conditions to give a series of resins with sulfonic acid capacities ranging from 0.27 to 2.63 mmol/g. Each of the resins was packed into a conventional column and used for HPLC separation of various substituted benzenes using acetonitrile–water solutions as the mobile phase. In a mobile phase of acetonitrile–water (30:70), a nearly linear decrease in retention factor with increasing sulfonic acid capacity was noted for a set of substituted benzenes (polar and non-polar). The retention factors at the highest sulfonic acid capacity studied (2.63 mmol/g) were only 0.10 to 0.16 that of the unsulfonated resin. The sulfonated resins were also used for quasi-normal-phase separations of polar analytes such as glycols and sugars. In binary acetonitrile–water mobile phases, retention factors increased in a regular fashion as the concentration of acetonitrile was increased from 70 to 95%. Retention factors of the same analytes also increased substantially with increases in sulfonic acid content of the resin.

Novel polymer-supported β-diketonate nickel catalysts for α-olefin activation

Styrene–divinylbenzene resins were used for the synthesis of different polymer-bound β-diketones, obtained by anchoring the chelating group through either the central or the lateral position. The heterogenized diketone ligand was subsequently reacted with Ni(COD)2 analogously to the corresponding homogeneous catalysts active in α-olefin oligomerization. The heterogenized catalysts showed a good activity only when the central position of the chelate moiety was free. Heterogenization caused a significant change of selectivity: olefin oligomerization was accompanied by the formation of a large amount of polymeric products. This behavior is discussed in terms of steric effects caused by the bulky polymeric ligand. © 1998 John Wiley & Sons, Ltd.

Novel polymer‐supported β-diketonate nickel catalysts for α-olefin activation

Styrene–divinylbenzene resins were used for the synthesis of different polymer-bound β-diketones, obtained by anchoring the chelating group through either the central or the lateral position. The heterogenized diketone ligand was subsequently reacted with Ni(COD)2 analogously to the corresponding homogeneous catalysts active in α-olefin oligomerization. The heterogenized catalysts showed a good activity only when the central position of the chelate moiety was free. Heterogenization caused a significant change of selectivity: olefin oligomerization was accompanied by the formation of a large amount of polymeric products. This behavior is discussed in terms of steric effects caused by the bulky polymeric ligand. © 1998 John Wiley & Sons, Ltd.

Novel polymeric resins for anion-exchange chromatography

A novel anion-exchange resin containing three amine groups was prepared by reaction of a chloromethylated polystyrene–divinylbenzene (PS–DVB) resin with diethylenetriamine. After being protonated by contact with an aqueous acid, this resin can be used for ion-chromatographic separation of anions. The charge on the resins can be varied from +1 to +3 by changing the pH at which the ion chromatographic separation was carried out. The selectivity of the new ion exchangers for various inorganic anions was quite different from conventional anion exchangers. The performance of this new anion exchanger was studied by changing the pH and the concentration of the eluent, and several different eluents were used with some common anions as testing analytes. Conductivity detection and UV–Vis detection were applied to detect the anions after separation. The new resin can also be used for HPLC separation of neutral organic compounds. Alkylphenols and alkylbenzenes were separated with this new polymeric resin, and excellent separations were obtained under simple conditions.

Aldehyde separation by polymer-supported oligo(ethyleneimines)

Chlorosulfonated styrene (10%) divinylbenzene resin beads reacted with an excess of ethylenediamine (EDA), diethylenetriamine (DETA), and triethylenetet- ramine (TETA) to give the corresponding sulfonamides with pendant oligo(ethylenei- mines). The resulting modified resins are useful in the separation of aldehydes from hydrocarbon mixtures. Sorption of aldehydes occurs through formation of both Schiff base and five-membered (imidazoline) rings. Sorbed aldehydes can readily be stripped from the resins by treating with dilute acid solutions. Since the sulfamide bond has a reasonable stability toward acid-base hydrolysis, the loaded resins can be regenerated and recycled by simple acid-base washings, without losing their activity. In the present study, sorption and desorption kinetics of acetaldehyde, benzaldehyde, and salicylalde- hyde have been investigated under different conditions. The aldehyde sorption obeys second-order kinetics. The method presented is applicable for all aromatic aldehydes. However, in the case of aliphatic aldehydes carrying an a-hydrogen, aldol condensation products form in solution. So aliphatic aldehydes and their aldol products are sorbed together by the resins. This limits the recovery of aliphatic aldehydes. Consequently, the resins described are cost effective sorbents for the removal and recovery of aromatic aldehydes from various mixtures. q 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 2857-2864, 1997

Enrichment of Boron-10 by Inverse-Frontal Chromatography Using Quaternized 4-Vinylpyridine—Divinylbenzene Anion-Exchange Resin

In order to enrich 10B, 40 meter band migration of boric acid—mannitol with hydrochloric acid solution was performed by inverse frontal chromatography on a porous, 25% crosslinked, 38% quaternized 4-vinylpyridine—divinylbenzene resin. The maximum enrichment (R L) of 10B was 94.15%. The overall process parameters, namely slope coefficient (k) and separation coefficient (ε), were found to be 0.1282 cm−1 and 0.02967, respectively.

Lead complexation in wines with the dimers of the grape pectic polysaccharide rhamnogalacturonan II

<p style="text-align: justify;">Wine is believed to be a significant source of lead in the human diet even though the lead content of wines has decreased considerably over the last thirty years. Nevertheless, the lead content of wines must be reduced to a minimum since this heavy metal is highly toxic.</p><p style="text-align: justify;">The plant cell wall pectic polysaccharide rhamnogalacturonan Il (RG-II) is a predominant anionic molecule in red wine. RG-Il exists as a dimer (dRG-Il-B) that is cross-linked by a 1:2 borate-diol ester and forms complexes <em>in vitro</em> with lead and other selected di- and tri-valent cations. One mole of dimer binds at least 1 mole of Pb<sup>2+</sup>. We have now determined the amount of lead in wines that is bound to dRG-II-B since previous studies have suggested that most of the lead in wine is bound to an anionic macromolecule.</p><p style="text-align: justify;">Seven wines, with lead concentrations between 30 and 110 μg/l, were obtained from different grape varieties harvested at different vintages and vinified by different procedures. Two chromatography steps, adsorption on a polystyrene- divinylbenzene resin and size-exclusion on a Superdex® 75-HR column, have been used to purify a d-RG-II-B-lead complex which contained at least 85 p. cent of the total lead of each wine. The dRG-II-B-Pb complex is stable at the pH of wine and is present in a wine that was procluced in 1988. The dRG-II-B present in red (~ 100 mg/l) and white (~ 20 mg/l) wines can bind at least ten-fold more Pb<sup>2+</sup> than is typically present in wine.</p><p style="text-align: justify;">Our study is the first to show that in wine most of the lead is complexed with a pectic polysaccharide that is not degraded during vinification. dRG-II-B is also known to form complexes with other cations, including strontium and barium. However, it is not known what role dRG-II-B has in determining the metabolic fate in humans of toxic cations present in wine.</p>

Use of contrast-enhanced small-angle neutron scattering to monitor the effects of solvent swelling on the pore structure of styrene–divinylbenzene resins

The pore structure of series of porous styrene–divinylbenzene resins has been monitored both in the non-swollen state and when swollen with a range of solvents of varying Hildebrand solubility parameter using small-angle neutron scattering. It has been shown that the Porod scattering invariants increase as swelling increases, indicating an increase in the interfacial scattering surface area. For the sample prepared with a relatively small amounts of porogen during polymerization, the scattering curves of the acetic acid and toluene swollen samples each consist of two linear regions up to ca. 45 A is size, corresponding firstly to scattering from swollen, highly crosslinked regions and secondly to mass fractal aggregates of these regions. Samples produced with higher amounts of porogen have a surface fractal structure in the swollen state. Porosity that is closed to the external surface in dry samples is accessible to swelling solvents.

Solid-State 13C MAS NMR Studies of Hyper-Cross-Linked Polystyrene Resins

13C CP/MAS NMR techniques have been used to evaluate the structure of four hyper-cross-linked polystyrene resins. Single-pulse excitation (SPE) 13C spectra have allowed the various types of carbon atoms present in the resins to be quantified, and similarly 1H CRAMPS spectra have facilitated quantification of the various hydrogen atom types. Two hyper-cross-linked resins prepared by exhaustive methylene bridging of conventional lightly cross-linked styrene−divinylbenzene resins have very high quaternary aromatic carbon contents. These can be explained adequately only if very high levels of double methylene bridging of aromatic groups occurs. Approximately 10% of aromatic groups also retain a chloromethyl group from incomplete methylene bridging. Two further hyper-cross-linked resins reportedly prepared from conventional heavily cross-linked divinylbenzene (55% technical grade) resins appear in one instance to exploit residual unreacted double bonds (and possibly additional divinylbenzene) to generate the secondary cross-links, and in another to use SOCl2/Lewis acid to introduce very high levels of sulfoxide secondary cross-links. Dynamic NMR experiments suggest that the latter two hyper-cross-linked species retain more flexibility and mobility than those prepared via more conventional methylene bridging techniques.

Use of contrast matching small-angle neutron scattering to monitor the presence of closed porosity in controlled porosity styrene–divinylbenzene resins

A series of styrene–divinylbenzene resins produced with varying amounts of toluene as a porogen have been investigated using contrast-matching small-angle neutron scattering. The results show the existence of some microporosity in the samples that cannot be accessed by a weakly swelling solvent, ethanol. Also, when the amount of porogen used in the production of the samples is low, a significant amount of the macroporosity is closed. The implications of this for the industrial application of these materials is discussed.

A study on the preparation and properties of the heterogeneous cation‐exchange membranes of sulfonated polystyrene/divinyl benzene on an acetal base

AbstractThe heterogeneous acetal‐based membranes containing 50, 60, 70, 80, and 90% (w/w) of the sulfonated polystyrene crosslinked with 7% divinyl benzene were fabricated and studied. In addition, the heterogeneous acetal‐based membranes of 85% (w/w) sulfonated polystyrene crosslinked with 1, 4, and 7% divinyl benzene were also prepared and studied. The gel water content, dimensional stability, ion‐exchange capacity, area and specific ohmic resistance, permselectivity, and rate of ion exchange of the acetal‐based membranes were determined. The sulfonated polystyrene crosslinked with 7% divinyl benzene resin was found to be the better material for preparing the acetal‐based membrane with comparable good characteristics. A commercially available heterogeneous membrane (Shanghai Chemicals, 3361) of dry‐molding sulfonated polystyrene–divinyl benzene resin was used as the reference membrane for the present investigation. © 1995 John Wiley & Sons, Inc.

Solid‐phase peptide synthesis on a novel hydrogenolysable linker–resin combination

AbstractThe propensity of benzyloxycarbonylamide group towards clean and rapid hydrogenolysis was exploited in designing a linker for solid phase peptide synthesis on a copoly(styrene–divinylbenzene) resin support. Hydroxymethyl copoly(styrene–divinylbenzene) on treatment with 4‐nitrophenyl chloroformate gave a resin which possessed benzyl 4‐nitrophenyl carbonate pendants. These reacted with the α‐amino group of Boc–Lys–OMe, resulting in the attachment of the latter through its side chain to the resin by a benzyloxycarbonylamide linkage. This was used to extend the peptide chain from the α‐amino end of lysine by Bocmethodology. The peptide was released from the resin through palladium acetate–ammonium formate‐based transfer hydrogenolysis. The usefulness of this linker was demonstrated by synthesizing several small peptides terminating in lysine. © 1995 John Wiley & Sons, Inc.

Limonoid Glucosides in Fruit, Juice and Processing by‐products of Satsuma Mandarin (Chus unshiu Marcov.)

ABSTRACTIn a study on improving utilization of waste from processing of Satsuma mandarin (Citrus unshiu Marcov.) the limonoid glucosides of fruit, juice, and by‐products were measured using HPLC and TLC. All materials had the 17‐β‐D‐glucopyranoside derivatives of limonoids reported in other commercial citrus fruit. Citrus molasses was a good source for industrial scale extraction of limonoid glucosides. An extraction system using polystyrene divinylbenzene resins, was developed which could be expanded to industrial scale.

Novel heterobifunctionalized polystyrene-polyethylene glycol resin for simultaneous preparation of free and immobilized peptides and biological activity detected by confocal microscopy

Fast and convenient binding assays using synthetic peptides are of utmost and increasing importance, especially in the search for lead structures or in the field of diagnostics. A polymeric support suitable for solid-phase peptide synthesis was functionalized with two different anchor groups. The interior part of the aminomethylated polystyrene-1%-divinylbenzene resin beads, comprising about 98% of the total loading capacity, was modified by the acid-labile ADPV anchor whereas the 2% outer surface of the polymer was covalently coated with a PEG 10 000 derivative which renders the resin surface hydrophilic and biocompatible. The novel resin was characterized by introducing marker amino acids and by infrared spectroscopy. Employing this bifunctionalized resin for peptide synthesis, free as well as polymer-bound peptides were obtained which were tested for recognition by antibody. The resin-bound peptides proved to be suitable for ELISA and fluorescence assays, as shown by confocal laser microscopic investigations. Peptides from the interior part were obtained in high yield and purity as analyzed by HPLC, electrospray mass spectrometry and Edman degradation.

Novel polystyryl resins for size exclusion chromatography

AbstractNew size exclusion chromatography (SEC) resins based on a crosslinker having independent vinyl groups have been produced and compared with SEC resins based on divinylbenzene‐55 (DVB). 1,2‐Bis(p‐vinylphenyl)ethane (p,p‐BVPE) and its meta‐isomers were suspension‐copolymerized with p‐methylstyrene in the presence of different porogens to give particles of about 5 μm average diameter. The porous particles were slurry‐packed into stainless steel columns for SEC evaluation. Calibration curves were obtained using narrow disperse polystyrene standards with molecular weights ranging from 580 to 3,040,000. The calibration curves for the new BVPE resins covered wider useful molecular weight ranges than those for comparable divinylbenzene resins. Particle size, surface morphology and the properties of pores were studied using a Coulter Multisizer II, scanning electron microscopy, nitrogen adsorption, and mercury porosimetry. © 1994 John Wiley & Sons, Inc.

Liquid–solid disk extraction followed by supercritical fluid elution and gas chromatography of phenols from water

AbstractA method combining the techniques of liquid – solid disk extraction (LSDE) and supercritical fluid elution (SFE) has been developed for the phenols regulated by the Clean Water Act. LSDE uses a disk or membrane made of polytetrafluoroethylene (PTFE) fibrils impregnated with small particles, e.g. styrene divinylbenzene (SDB) resin, to extract phenols from water. After disk extraction the retained analytes are eluted from the disk using SFE. SFE is used as an alternative to liquid solvent elution with an organic solvent. Analytes are separated, identified, and quantified using gas chromatography – ion trap detector mass spectrometry (GC‐ITDMS). The method is capable of sub parts per billion detection limits, and precision of 5–28% RSD. Evaluation of various disks or membranes, such as C18‐silica disks, SDB disks, and ion exchange membranes, has also been performed for the extraction of phenols from water. The results obtained from the in‐situ aqueous acetylation of phenols and extraction of their acetates are quantitative. The utilization of LSDE and SFE techniques has proven to be a more effective approach than liquid – liquid extraction in minimizing air pollution and solvent waste.