Use of ion-selective electrodes for monitoring oscillating reactions. 1. Potential response of the silver halide membrane electrodes to hypohalous acids

NMR Measurements.The proton NMR spectra of three solutions of choline chloride plus NaOH in D20 and one of choline chloride alone in D20 were recorded on a Varían T-60 spectrometer at 42.5 °C.The quaternary methyl peak was observed at 5 3.2 in all four samples, indi- cating no observable interaction between this group and hydroxide ion and no decomposition.The -methylene resonances, at about <5 3.4, were found to shift steadily upfield on addition of NaOH.By use of this shift, the percent of anhydrocholine formed was calculated and compared with that calculated from our aqueous AH and AS values (Table VI).Considering the very large concentrations that had to be used and the change from H20 to D20, the agreement is quite reasonable.This experiment was repeated in H20 solvent with similar results.Calorimetry.Heats of solution were measured with an LKB-8700 reaction and solution calorimeter.