Factors affecting reaction rates in polystyrene beads used in solid phase organic synthesis have been studied. The role of diffusion and reagent partitioning has been examined theoretically and experimentally. Both of these factors have been found to influence the reaction kinetics of common solid phase organic synthesis reactions. A mathematical model to analyze a simple bimolecular reaction inside a bead has been developed and successfully applied to the experimental data to obtain quantitative information on the influence of diffusion and reagent partitioning on the reaction rates. The effects of diffusion generally increase with the size and decreased swelling of the beads. Under many common reaction conditions, however, these effects may not be very significant. General guidelines to identify these conditions have been developed. A water-soluble torsion balance to study noncovalent interactions in aqueous media has been synthesized. The folding energies of new balances were found to be higher in water than in organic solvents. This increase can be partially attributed to hydrophobic forces. Aggregation and micelle formation were found to increase folding in water, indicating differences between microscopic and mesoscopic hydrophobic effects. The experimental data have been analyzed in the context of the Lum, Chandler and Weeks theory of hydrophobicity and evidences in its favor have been found. The hydrophobic response of a fluoromethyl group was found to be similar to a methyl group in two complementary torsion balances.<br /
