Silica compounds poly synthesis

Gitsov et al 10) produced a nanoreactor fi om laccase and linear poly(ethylene oxide)-dendritic poly(benzyl ether) diblock copolymers. A notable feature of this system is the presence of hydrophobic dendritic pockets that increase the local concentration of water-insoluble organic compounds near the active site where they are oxidized. Li and Hsieh (77) employed a hydrogel fiber membrane, with a large surface area and improved organic solvent solubility in order to facilitate lipase reactions. He (72) grafted lipase onto silica particles, which permitted him to carry out synthesis of polyesters, polycarbonates, polyphosphates, and their copolymers at temperatures up to 150°C. 

Chiral polymers can be obtained in two different ways. The use of a chiral catalyst during polymerization can lead to helical structures, as observed in polysaccharides. The other synthesis path uses chiral monomers, which are polymerized to give a chiral polymer capable of folding to a supramolecular stmcture [20]. For application in HPLC, all of these polymers must be coated onto silica, since they are imable to withstand the high pressures encountered in HPLC. Currently, chiral stationary phases based on polyacrylates or polymethacrylates play only a minor role. Chirasphere (Merck) is derived from a silica material coated with poly(N-acryloyl-(S)-phenylalanine ethyl ester) and can be used for the separation of P-blockers in the normal-phase mode. The chiral polymethacrylates Chiralpak OP and Chiralpak OT (Daicel) are able to separate aromatic compounds into their enantiomers. 

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