Kinetics of intramolecular and intermolecular reactions involving two functional groups attached to polymers
ABSTRACT Three types of investigations are described, (a) When a polymer chain carries reactive substituents, the reaction rate may be increased by very large factors if these groups are sufficiently close to each other. More distant groups interact at rates governed by the chain flexibility. A technique is described for studying the effect of the excluded volume on the probability of cyclic chain conformations. (b) When reactive and catalytic substituents are attached to different polymer chains, their reaction should be hindered by the resistance of polymer coils to mutual interpenetration in good solvent media. Two theoretical approaches to this ‘kinetic excluded volume effect’ are described. Experimental data do not conform to the expected behaviour and the reason for this discrepancy is unknown, (c) Crosslinked polyacrylamide beads carrying nucleophilic substituents were evaluated as catalysts for the solvolysis of nitrophenyl esters in a solution phase. Under certain conditions, groups attached to the gel were much more efficient catalysts than their analogues in homogeneous solution. This effect was ascribed to a cooperative action of two catalytic groups.