GAS-PHASE S(N)2 NUCLEOPHILIC DISPLACEMENT-REACTIONS AT ATMOSPHERIC-PRESSURE BY THE PHOTODETACHMENT-MODULATED ELECTRON-CAPTURE DETECTOR

Rate constants for the reactions of Cl- ion with 20 different alkyl br omides (RBr) have been measured at 125 degrees C in an atmospheric pre ssure buffer gas by the photodetachment-modulated electron capture det ector (PDM-ECD). By this method, the relative concentrations of the re actant ion, Cl-, and the product ion, Br-, are spectroscopically measu red in a steady-state reaction volume with various concentrations of p urified RBr introduced to the ion source by gas chromatography. Most o f the reactions reported here have not been previously studied and, th erefore, the present data set provides additional insight into substit uent effects in gas phase S(N)2 reactions.