PHASE-TRANSFER REACTIONS CATALYZED BY PHOSPHONIUM SALTS ATTACHED TO POLYSTYRENE RESINS BY SPACER CHAINS

In the reported experiments, the rate of reaction of 1-halooctanes with aqueous sodium cyanide catalyzed by phosphonium salts attached to insoluble polystyrene resins by tetramethylene or heptamethylene spacers was studied as a function of catalyst particle size, degree of polymer crosslinking, percentage of ring substitution, and temperature. Rates of reaction of 1-bromooctane decreased, whether the percentage of ring substitution increased or decreased from 17-19%. Rates of reaction of 1-chlorooctane increased with increasing spacer-chain length and decreasing percentage of ring substitution. Apparent activation energy for the reaction of 1-bromooctane with 9% ring-substituted, space-modified catalysts was 9-10 kcal/mol and 13 kcal/mol with 17-19% ring-substituted catalysts. The hydrophilicity of catalysts decreased with increasing spacer-chain length and decreasing percentage of ring substitution. The mechanisms of reaction were discussed in terms of intrinsic reactivity and intraparticle diffusion limitations on the reaction rates.