Measurement of Enthalpies of Reaction and Ionization Constants of Bicarbonate in Light And Heavy Water at Low Temperatures for Quantification of the Deuterium Isotope Effect

Abstract

This project aims to quantify the deuterium isotope effect of acid-base reactions using Isothermal Titration Calorimetry (ITC). This is achieved through the measurement of ionization constants (pK_a) and a enthalpies of reaction (Δ_rH°), to derive ΔpK_a , and ΔΔ_rH° in light and heavy water reactions. In select systems, pKa and Δ_rH° can be measured simultaneously. When reactant concentration falls outside the r operating range of the instrument, a conductivity probe will be used in future studies to measure ionization constants separate from reaction enthalpies. Bicarbonate, being a primary reference standard in light water titration calorimetry, is an ideal initial system for study in heavy water. These experiments will be conducted in the temperature range of 10-40°C, with the ability to extrapolate results higher using the extended van’t Hoff equation. Results will be used to create heavy water chemical equilibrium models for industrial nuclear reactor application.