Polystyrene crosslinked

Preparation of a Cation Exchanger by Sulfonation of Crosslinked Polystyrene 

Safety precautions More this experiment is carried out, Sect. 2.2.5 must be read as well as the material safety data sheets (MSDS) for all chemicals and products used. 

Insoluble polystyrene crosslinked with divinylbenzene can easily be converted by sulfonation to a usable ion exchanger. For this purpose a mixture of 0.2 g of silver sulfate and 150 ml of concentrated sulfuric acid are heated to 80-90 °C in a 500 ml threenecked flask fitted with stirrer, reflux condenser, and thermometer. 20 g of a bead polymer of styrene and divinylbenzene (see Example 3-41) are then introduced with stirring the temperature climbs spontaneously to 100-105 °C.The mixture is maintained at 100 C for 3 h,then cooled to room temperature and allowed to stand for some hours. Next the contents of the flask are poured into a 11 conical flask that contains about 500 ml of 50% sulfuric acid. After cooling, the mixture is diluted with distilled water, and the gold-brown colored beads are filtered off on a sintered glass filter and washed copiously with water. 

Preparation of an Anion Exchanger from Crossiinked Polystyrene by Chloromethylation and Amination 

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Ion-exchange Resins. An ion-exchange resin is made up of particles of an insoluble elastic hydrocarbon network to which is attached a large number of ionisable groups. Materials commonly used comprise synthetic ion-exchange resins made, for example, by crosslinking polystyrene to which has been attached non-... 

For quantitative analysis of solid supported thiol residues on free macroporous or PEG grafts, Ellman s reagent has been used [5,5 -dithio-hfr-(2-nitrobenzoic acid]. However only qualitative information can be gained using lightly crosslinked polystyrene resins [Badyal et al. Tetrahedron Lett 42 8531 2007]. 

An example of a Maugis-Pollock system is polystyrene particles having radii between about 1 and 6 p.m on a polished silicon substrate, as studied by Rimai et al. [64]. As shown in Fig. 4, the contact radius was found to vary as the square root of the particle radius. Similar results were reported for crosslinked polystyrene spheres on Si02/silicon substrates [65] and micrometer-size glass particles on silicon substrates [66]. 

Aryl-5-oxo-1,2,3,5-tetrahydropyrido[ 1,2,3-i/e]quinoxaline-6-carboxy-mides were prepared from 7-chloro derivatives and arylboronic acids in the presence of Na2C03, diphenylphosphinated divinylbenzene-crosslinked polystyrene and Pd(PPh3)4 catalyst. 7-Chloro derivatives were obtained from 7-hydroxy derivatives by heating in POCI3 at 50°C for 3 h (01MIP12). 

Hie hydrolytic depolymerization of nylon-6 was followed by gel permeation chromatography (GPC), viscometry, and gravimetry. GPC determinations were performed on a Waters 150C chromatography system using benzyl alcohol as die eluant, two Plgel 10-p.m crosslinked polystyrene columns, and a differential refractometer detector. The flow rate was 1 mL/min. The concentration of the polymer solutions was 0.5 wt% and dissolution was accomplished at 130°C. 

Modes of attachment of functional groups to crosslinked polystyrene are discussed ( 1). Attention is drawn to improved stability and activity of polymer-bound reagents and catalysts incorporating dimethylene spacer between polystyrene aryl and functional group heteroatom, and the simplicity and versatility of their synthesis through high-conversion functional group modifications. 

C10Hlo)o.01 C8H8 0.57 (c8H7Br)o.42 (Bromo)polystyrene (20.00 g, 60 meq), originally prepared from commercial 1% crosslinked polystyrene resin (37), was suspended in 500 ml dry benzene under nitrogen. Into this pale orange suspension was injected 2.2 M nBuLi/hexane (60 ml,... 

The SANS experiments of Clough et al. (21) on radiation crosslinked polystyrene are presented in Figure 9, and appear to fit the phantom network model well. However, these networks were prepared by random crosslinking, and the calculations given are for end-linked networks, which are not truly applicable. 

Amphiphilic resin supported ruthenium(II) complexes similar to those displayed in structure 1 were employed as recyclable catalysts for dimethylformamide production from supercritical C02 itself [96]. Tertiary phosphines were attached to crosslinked polystyrene-poly(ethyleneglycol) graft copolymers (PS-PEG resin) with amino groups to form an immobilized chelating phosphine. In this case recycling was not particularly effective as catalytic activity declined with each subsequent cycle, probably due to oxidation of the phosphines and metal leaching. 

Abstract Performances of Zr(IV) loaded Diaion CRP200 (crosslinked polystyrene based... 

Gentiotetraose, an all ()-(I —>6)-l inked tetramer of glucose was selectively prepared by Gagnaire and coworkers (Scheme 1.4).19 6-0-Trichloroacetylated glucosyl bromide 27 was attached to succinoylated 2% crosslinked polystyrene. After selective... 

By comparison, the synthesis of SIN s involved a castor oil derived crosslinked elastomer and crosslinked polystyrene as... 

Table 1. Glass Transition Temperature of SIN s Based in Castor Oil Elastomers and Crosslinked Polystyrene (%V...

Based on castor oil derived elastomers and crosslinked polystyrene, a simultaneous mode of polymerization can be successfully employed to synthesize prototype engineering materials such as tough, impact resistant plastics and reinforced elastomers. 

Polystyrene can be exceptionally crosslinked, leading to a tough and transparent material with improved electrical and thermal properties used as a dielectric material. Table 4.34 displays examples of crosslinked polystyrene properties. The data cannot be used for designing. 

Table 4.36 relates to examples only and cannot be generalized. The data cannot be used for designing. See also Table 4.34 for crosslinked polystyrene properties and Table 4.35 for foam properties. 

There are reports of numerous examples of dendritic transition metal catalysts incorporating various dendritic backbones functionalized at various locations. Dendritic effects in catalysis include increased or decreased activity, selectivity, and stability. It is clear from the contributions of many research groups that dendrimers are suitable supports for recyclable transition metal catalysts. Separation and/or recycle of the catalysts are possible with these functionalized dendrimers for example, separation results from precipitation of the dendrimer from the product liquid two-phase catalysis allows separation and recycle of the catalyst when the products and catalyst are concentrated in two immiscible liquid phases and immobilization of the dendrimer in an insoluble support (such as crosslinked polystyrene or silica) allows use of a fixed-bed reactor holding the catalyst and excluding it from the product stream. Furthermore, the large size and the globular structure of the dendrimers enable efficient separation by nanofiltration techniques. Nanofiltration can be performed either batch wise or in a continuous-flow membrane reactor (CFMR). 

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