Kinetics and mechanism of the reactions of aryl chlorodithioformates with pyridines and secondary alicyclic amines

摘要

The reactions of pyridines and secondary alicyclic (SA) amines with phenyl and 4-nitrophenyl chlorodithioformates(PCIDTF and NPCIDTF, respectively) are subjected to a kinetic study in aqueous ethanol (44 wt% ethanol) solution, at25.0°C, and an ionic strength of 0.2 M (KCI). The reactions are studied spectrophotometrically. Under amine excess,pseudo-first-order rate coefficients (kobs) are found. Plots of !cobs versus [amine] are linear and pH independent, withslope kN. The Bronsted-type plots (log kN vs. pKa of aminium ions) are linear for the reactions of PCIDTF with SA amines(slope