Polystyrene-divinylbenzene crosslinked

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). 

Removal of diluent by an extraction process To obtain the final stable macroporous structure, the liquid organic diluents and the linear polymer are removed from the crosslinked structure by extraction with a good solvent for the inert diluents and particularly for the linear polymer. Toluene or methylene chloride are usually preferred for the removal of linear polystyrene from the divinylbenzene crosslinked macroporous polystyrene particles [125,128]. The extraction is carried out within a Soxhelet apparatus at the boiling point of the selected solvent over a period usually more than 24 h. 

NTA nitrilotriacetate, EDTA = ethylenediaminetetraacetate, and Chelex 100 a crosslinked polystyrene divinylbenzene porous lattice with attached iminodiacetate multidentate functional groups. 

Examples of particle sizing using photon correlation spectroscopy are presented to demonstrate the straight forward uses and difficulties with the technique. Examples include NBS SRM 1691, a crosslinked polystyrene-divinylbenzene, a fractionated sample of polyvinylchloride, "dusty" samples of reference latex, a bimodal mixture of reference latices, a bimodal mixture of rubber particles, and a 2 1 aggregate. 

Figure 9.1. Representation of crosslinked polystyrene-divinylbenzene polymer structure.

Crosslinked Polystyrene. Polystyrene lightly crosslinked during polymerization by 0.01-0.25% divinylbenzene provides foams, expanded by carbon dioxide or other gases, with greater expandability and resistance to collapse at elevated temperatures (102, 103). Other divinylbenzene copolymers are reported, employing as blowing agent saturated aliphatic or fluoroaliphatic volatile liquids, tetramethylsilane, and azobis-isobutyronitrile (99,106, 108). 

Macroreticular polystyrene beads crosslinked with 20% divinylbenzene and containing p-aminostyrene units were converted with (9e, f) in THF into the polymers (32) and (33) (Eq. 13). The unconverted add ddoride grou[ of the polymer bond porphyrins were converted with methanol into the corresponding esters. 

Fig 1. Frontal loading adsorption isotherms of conventional "wide pore" derivatised silica (Brownlee RP-300) and macroporous divinylbenzene crosslinked polystyrene (Poros RII/H) supports. Protein 1 mg/ml solution in aqueous 0.1% TFA. Superficial linear flow velocities 347, 866, 1732 and 3465 cm/h. Temperature 25°C. (A) RP-300 2.1 mm ID cartridge. (B) Poros RII/H 2.1 mm ID column. 

The corresponding AminoPac PA-1 latex anion exchanger consists of a polystyrene/ divinylbenzene substrate with a particle diameter of 10 pm. The synthesis of the latex beads is carried out, however, using dimethylamine instead of divinylbenzene for crosslinking the polymer. Until now, no methods have been available for the separation... 

Commercially available Amberlite IR-120 (H -form) was used as an acid catalyst this resin is a divinylbenzene-crosslinked partially sulfonated gel-type polystyrene. As a base catalyst, PEG-PS resin-supported proline was employed. The reaction was performed in water-acetone-tetrahydrofuran (1 1 1 v/v/v) at room temperature in the presence of 20 mol. % of resin-supported proline and Amberlite. After 20 h, the reaction mixture contained the starting 4-nitro-benzaldehyde dimethyl acetal, 4-nitrobenzaldehyde and the corresponding aldol product with acetone in a ratio of 4 9 87. This means that both the... 

There are two popular stationary-phase materials. Polystyrene-divinylben-zene resins are useful materials, and the pore size can be easily controlled by the amount of divinylbenzene crosslinking. Silica and derivatized silica are also heavily used, and provide better mechanical rigidity. The problem with these and all packings used for SEC is to find a material that will be tmly inert to all chemical interactions with the solutes. 

FIXED NEGATIVELY CHARGED EXCHANGE SITE, J. E. S05 MOBILE POSITIVELY CHARGED EXCHANGEABLE CATION I. E., Na+ = POLYSTYRENE CHAIN S2S DIVINYLBENZENE CROSSLINK... 

Rohm and Haas XE 305 polystyrene beads crosslinked with 3-5% divinylbenzene were used. 

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