Halogen Exchange Reactions of Benzyl Halides Part -Kinetics of Reactions of Bromide and Iodide Ions with Benzyl Chloride and Bromide in Absolute Acetone

[摘要] Halogen exchange reactions of benzyl halides have been studied in absolute acetone. Rate constants were calculated using an integrated rate expression derived for the reaction involving ion-pair association. The order of nucleophilicity of halide ions in acetone was found to be a reverse of the order in 90% aqueous enthanol solvent. This was interpreted by means of HSAB principle and solvation of halide ions. Net increase in rate of reaction in acetone compared with the rate in protic solvent resulted from large increase in ¥ÄS¡Á rather than decrease in ¥ÄH¡Á. The solvation of the transition state also contribute to the net increase in rate.

[学科分类] 化学（综合）