Divinylbenzene pore glass

Polypeptide Synthesis and Analysis. Sihca or controUed-pore glass supports treated with (chloromethyl)phenylethyltrimethoxysilane [68128-25-6] or its derivatives are replacing chloromethylated styrene—divinylbenzene (Merrifield resin) as supports in polypeptide synthesis. The sdylated support reacts with the triethyl ammonium salt of a protected amino acid. Once the initial amino acid residue has been coupled to the support, a variety of peptide synthesis methods can be used (34). At the completion of synthesis, the anchored peptide is separated from the support with hydrogen bromide in acetic acid (see Protein engineering Proteins). 

A variety of materials are used as stationary phases for size-exclusion chromatography, including cross-linked dex-tran, polyacrylamide, agarose, polystyrene-divinylbenzene, porous glass, and combinations of the above. Beads of these materials are porous with pore sizes that allow small molecules to be temporarily entrapped. Molecules too large to enter the pores remain entirely in the mobile phase and are rapidly eluted from the column. Molecules that are intermediate in size have access to various fractions of the pore volume and elute between the large and small molecules according to the relation ... 

Size-exclusion Molecular size Sulfonated divinyl benzene Divinylbenzene Silica gel Porous gel Aqueous gel Organic gel Controlled pore silica Controlled pore glass... 

Oligodeoxynudeotide synthesis today is virtually always carried out on a solid support. Initially, the polymeric solid supports were polystyrene cross-linked with divinylbenzene, but controlled-pore glass beads (CPG beads) with defined porosities are now used in preference. The 3 -hydroxyl of the first protected deoxynucleotide is precoupled to the solid support and then solid phase, multistage oligodeoxynudeotide synthesis may commence in the 3 5 direction, in direct analogy to SPPS (Figure 2.5). 

New polymeric solid supports have been devised, which include macroporous styrene-divinylbenzene containing large fixed pores, porous glass beads, insoluble carbohydrate polymers, poly(ethylene oxide), cross-linked derivatives of polyacrylamide resins, and graft copolymers of polystyrene and poly(ethylene oxide). The last two have been the most effective and widely used and have competed well with the original copoly(styrene-divi-nylbenzene) beads. 

The precipitation polymerization takes place in a batch reactor. Azoisobutyronitrile is used as the radical initiator, and styrene and divinylbenzene were chosen as monomers. A solution of the monomers in a long-chain hydrocarbon liquid is prepared [23]. After a clear solution has formed the megaporous glass Raschig rings are immersed in the solution, vacuum was used to remove the air from the pores, and the polymerization was initiated by heating. Fig. 8.7 shows the course of the precipitation polymerization in the pore volume of the carrier. 

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