Polymer support materials

New templated polymer support materials have been developed for use as re versed-phase packing materials. Pore size and particle size have not usually been precisely controlled by conventional suspension polymerization. A templated polymerization is used to obtain controllable pore size and particle-size distribution. In this technique, hydrophilic monomers and divinylbenzene are formulated and filled into pores in templated silica material, at room temperature. After polymerization, the templated silica material is removed by base hydrolysis. The surface of the polymer may be modified in various ways to obtain the desired functionality. The particles are useful in chromatography, adsorption, and ion exchange and as polymeric supports of catalysts (39,40). 

Our studies of chemically prepared catalyst powders in gas diffiision electrodes have demonstrated that conducting polymer supported catalysts can provide similar current densities to commercial carbon supported catalysts. They indicate that with further optimization, the ion conducting properties of certain polymer support catalysts may allow them to exceed the performance of carbon supported catalysts. However, it is clear that substantial improvements in the stability of the polymer support materials will have to be made before applications in fuel cells can be realized. 

The next step is to produce thin films of good quality. For obvious degradation reasons it is necessary to do this step in a glove box. Initially a homogeneous layer of standard catalyst is applied to a flat carrier consisting of stretchable polymer-supporting material, e.g. high-density polyethylene film or polypropylene film. 

Ten millilitres of the standard catalyst used previously in this section is mixed with different soluble reducing agents. An even, homogeneous layer of catalyst which is obtained by mixing 10 ml of catalyst, such as I ml of nBuLi, is applied to a flat carrier consisting of a polymer-supporting material (HOPE or polypropylene films). Acetylene is then introduced and allowed to react with this modified catalyst to give a new (CH) film. 

Svec Erantisek, and Regnier Ered E. Organic polymer support materials. In HPLC of biological molecules, Gooding K., Regnier E.E. (eds.), pp. 17-48. New York Marcel Dekker, 2002. 

Reductions of P-O Bonds. Phosphine oxides can be efficiently reduced to phosphines using stoichiometric amounts of Ti(0-/-Pr)4 and PMHS at 50 °C (vs. 250 C without Ti ). The reduction proceeds via a syn hydrotitanation and goes with retention of configuration when the phosphine oxide is chiral (eq 25). The PMHS/Ti reagent combination has also proven amenable to reaction with polymer supported materials. ... 

Gel-phase C NMR spectra were also recorded on the polymer-supported material at each step in the reaction sequence. Again, the loss or gain of the trimethylsilyl resonance at 8 0.3—0.5 ppm was a diagnostic feature. 

General Procedure. Merrifield s resin (1.1 mmol Cl/g, 1% crosslinker divinylbenzene copolymer, 70-90 mesh) was obtained from Aldrich Chemical Co. MacroKans were obtained from IRORI. ° FT-IR characterizations of the polymer-supported reactions were carried out by placing ca. 10 mg of the polymer-supported material on a NaCl plate. After the beads were swollen with 2-3 drops of CCI4, a second NaCl plate was pressed onto the beads, and an FTIR spectrum was recorded. 

An even, homogeneous layer of catalyst is applied onto a flat carrier consisting of glass or any other material, e.g. nylon, polyester film or other polymer-supporting material which is stretchable, e.g. polybutadiene. 

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