Grafted macroporous polymer monoliths: Polymer-assisted synthesis and other applications

Macroporous polymer monoliths have shown their utility in a variety of applications, ranging from chromatography to enzymatic immobilization and catalysis. However, for applications in synthetic organic chemistry such as polymer-bound supports and reagents, monoliths are quite unreactive. One way to increase the reactivity is through grafting.; Chapter 1 presents an overview of the preparation, characteristics, applications and limitations of macroporous polymer monoliths. In addition, a review of grafted polymeric supports is presented and different grafting methods discussed. A general method was developed for grafting to macroporous polymer monoliths and this is outlined in Chapter 2. The method proved to be applicable to grafting a number of monomers, so that a range of functionality could be introduced into the monoliths.; This general grafting method is applied in Chapters 3 and 4 to the preparation of monolithic materials for use in organic synthesis, such as a nucleophilic scavenging resin and an acylating reagent. When used in a flow-through mode, monoliths containing grafted functionality were found to be more than twice as reactive as those prepared directly from the reactive monomers. One advantage of using reactive resins in a flowthrough capacity is that different chemistries can be used in line, separating them in space and also in time.; The same grafting strategy is used again in Chapter 5 to make monoliths containing ionizable groups suitable for electroosmotic pumping. When monoliths were prepared directly from these monomers, small flow rates were observed along with undesirable high currents. Grafting solved this problem, and pumps with high flow rates capable of generating considerable amounts of pressure were prepared.; A different strategy was employed for grafting conducting polymer to the pore surface, as outlined in Chapter 6. A monomer containing a pyrrole group was synthesized and incorporated into a monolith. Grafting methods were employed which led to sizable amounts of polymer growth and slightly conducting monoliths. Chapter 7 describes the preparation of monolithic materials for applications in catalysis. Palladium porphyrin, a singlet oxygen sensitizer, and coumarin dyes were introduced into the monoliths, and efficient energy transfer between these two moieties was observed.