Grafted Macroporous Polymer Monolithic Disks:  A New Format of Scavengers for Solution-Phase Combinatorial Chemistry

Abstract

Polyethylene encased porous poly(chloromethylstyrene-co-divinylbenzene) disks have been prepared by polymerization in a cylindrical glass mold and cut to a disk format. Following attachment of a free radical azo initiator 4,4'-azobis(4-cyanovaleric acid) to available functionalities at the surface of the pores, the polymerization of 2-vinyl-4,4-dimethylazlactone was initiated from the surface. To avoid an undesirable increase in flow resistance and to improve the yield of grafting, divinylbenzene was added to the polymerization mixture in order to form a layer of swellable reactive polymer gel within the pores. The use of these disks as scavenging filters to remove various amines from solutions in flow-through operations was demonstrated by effective removal of amines in a very short period of time from their solutions in a variety of solvents, even including alcohols and water.

Preparation and HPLC applications of rigid macroporous organic polymer monoliths

“…In order to avoid an undesirable increase in flow resistance and to improve the yield of grafting, divinylbenzene was added to the polymerization mixture to form a layer of swellable reactive polymer gel within the pores. These monoliths were used for the separation of various amines from solutions in flow-through manner [75,76].…”

Acrylic Acid “Reversed” PolyHIPEs

“…This paradox can be addressed by preparing monoliths with large pores and subsequently grafting the functional groups onto the surface, as shown by the research group of Frechet, Š vec, and co-workers in Berkeley. [5] Researchers in the field of separation technology especially welcomed the development of monolithic supports and the earliest attempts to prepare and apply monolithic supports as separation media date back to the late 1960's. However, they were not very successful and further development did not immediately follow.…”

Less common applications of monoliths

“…Their applications in a variety of liquid chromatographic modes including high-performance liquid chromatography (HPLC) and capillary electrochromatography (CEC) has recently been described in several reviews [12][13][14][15][16][17][18][19][20][21][22][23][24][25] and books [11,26]. However, the less common applications of monolithic materials that include supports for solid phase and combinatorial synthesis [27][28][29], scavengers [30,31], carriers for immobilization of enzymes [32][33][34], static mixers [35], thermally responsive gates and valves [36][37][38], as well as solid phase extractors and pre-concentrators [39] are escaping the awareness of the scientific community. The recently started series of review articles aims at popularization of these applications.…”