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Deuterium Isotope Effects for Inorganic Oxyacids at Elevated Temperatures Using Raman Spectroscopy

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Deuterium Isotope Effects for Inorganic Oxyacids at Elevated Temperatures Using Raman Spectroscopy Deuterium Isotope Effects for Inorganic Oxyacids at Elevated Temperatures Using Raman Spectroscopy by Michael Boris Yacyshyn A Thesis presented to The University of Guelph In partial fulfilment of requirements for the degree of Master of Science in Chemistry Guelph, Ontario, Canada © Michael Boris Yacyshyn, August 2013 ABSTRACT DEUTERIUM ISOTOPE EFFECTS FOR INORGANIC OXYACIDS AT ELEVATED TEMPERATURES USING RAMAN SPECTROSCOPY Michael Boris Yacyshyn Advisor: University of Guelph, 2013 Professor P. R. Tremaine Polarized Raman spectroscopy has been used to measure the deuterium isotope - effect, pK = pKD2O – pKH2O, for the second ionization constant of sulfuric acid, DSO4 + 2- D + SO4 , in the temperature range of 25 °C to 200 °C at saturation pressure. Results for pK in light water agree with the literature within ± 0.034 pK units at all temperatures under study, confirming the reliability of the method. The ionization - constant of deuterated bisulfate, DSO4 , differs significantly from previous literature results at elevated temperatures. This results in an almost constant pK ≈ 0.425 ± 0.076 over the temperature range under study. Differences in pK values between the literature and current results can be attributed to the effect of dissolved silica from cell components. The new results are consistent with pK models that treat the temperature dependence of pK by considering differences in the zero-point energy of hydrogen bonds in the hydrated product and reactant species. 3- - 2- The phosphate hydrolysis equilibrium, PO4 + D2O OD + DPO4 , was measured between the temperatures of 5 °C and 80 °C and the borate/boric acid - - equilibrium, B(OD)4 OD + B(OD)3, between the temperatures of 25 °C and 200 °C. The high alkalinity and temperatures experienced by these two systems had a significant impact on the glass dissolution and equilibrium. ii Dedicated to my parents iii ACKNOWLEDGEMENTS First of all, I would like to thank my supervisor, Dr. Peter Tremaine, for guiding me through my graduate studies. His wisdom, in and out of the workplace, has made a significant impact on my life and I feel very privileged to have worked along side of him. I would also like to express my thanks to the remaining members of the hydrothermal research group. These members include: Kwame Agbovi, Chris Alcorn, Dr. Lucas Applegarth, Dr. Hugues Arcis, Katie Bissonette, Dr. Yohann Coulier, Dr. Jenny Cox, Kristy Erickson, Alex Lowe, Kate McCallum, John Noel, Jeff Plumridge, and Dr. Olivia Fandino Torres. I have shared a lot of laughs with you over my studies and plan to share many more. I would like to thank my advisory committee: Dr. Dan Thomas, Dr. Paul Rowntree, Dr. Aziz Houmam and Dr. Mark Baker. With their help I have completed a thesis of which I am truly proud of. Outside of the lab, I wish to thank Leah Williams for making my life wonderful and supporting me throughout my thesis. Big thanks to Hugues, Yohann and Eric for the awesome skateboarding sessions. I would also like to thank my Burlington friends and family for being supportive in my endeavours. Thank you Kathy Parker, Debbie Powers, Brenda Yacyshyn-Robson, Wayne Yacyshyn, Adrienne Baker, Jon Deboer, Emily Barham, Adam Etherington, Marcel Jordan, Ryan Joslin, Sara Trayes, Erin Etherington, Paul Hennessey, Anthony Cipolla, Jen Yaremko and Sean Deline. Most importantly, I would like to thank my parents Boris and Jane Yacyshyn for supporting me throughout my studies. I would not be where I am today without your help and I am eternally gratefully for everything you have done for me. iv TABLE OF CONTENTS ACKNOWLEDGEMENTS………………………………………………………………iv TABLE OF CONTENTS……………………………………………………………….....v TABLE OF FIGURES……………………………………………………………….…...ix TABLE OF TABLES………………………………………………...……………..…...xii LIST OF ABBREVIATIONS AND SYMBOLS…………………………………..…...xiii 1.0 INTRODUCTION .................................................................................................. 1 1.1 Overview............................................................................................................. 1 1.2 Scientific and Industrial Interest in Hydrothermal Chemistry............................ 3 1.2.1 Applications of Hydrothermal Chemistry to the Nuclear Industry............. 5 1.2.2 Metal Oxide Solubility................................................................................ 8 1.2.3 Effects of Isotopic Substitution on Physical and Chemical Properties of H2O ........................................................................................................... 13 1.3 Physical Properties of H2O and D2O ................................................................ 15 1.3.1 Hydrogen Bonding Effects with Temperature.......................................... 15 1.3.2 H2O vs P and T ......................................................................................... 20 1.3.3 D2O vs P and T ......................................................................................... 21 1.4 High Temperature Aqueous Chemistry ............................................................ 21 1.4.1 Thermodynamics....................................................................................... 21 1.4.1.1 Standard State....................................................................................... 21 1.4.1.2 Equilibrium Constant............................................................................ 22 1.4.2 Born Model of Solvation - Long Range Polarization Effects................... 25 1.4.3 Density model ........................................................................................... 27 1.4.4 Activity Coefficient Models ..................................................................... 28 1.4.4.1 Debye-Hückel Model............................................................................ 28 1.4.4.2 Guggenheim Equation.......................................................................... 29 1.4.4.3 Davies Equation.................................................................................... 30 1.4.4.4 Mean-Sphere Approximation................................................................30 1.5 Experimental Methods for Ionization Constant Measurements at High Temperatures......................................................................................................... 32 1.5.1 Solubility Measurements .......................................................................... 32 1.5.2 Electromotive Force (EMF) and Potentiometry ..................................... 344 1.5.3 AC Condunctivity Measurements........................................................... 355 v 1.5.4 Raman Spectroscopy................................................................................. 36 1.6 Deuterium Isotope effects................................................................................. 37 1.6.1 Solvation Effects at 298.15 K ................................................................... 38 1.6.1.1 Non-electrolytes.................................................................................... 39 1.6.1.2 Electrolytes ........................................................................................... 40 cid/Base Equilibria................................................................................. 41 1.6.3 Temperature Dependence of pK............................................................. 41 1.7 Fundamentals of Raman Spectroscopy............................................................. 44 1.7.1 Polarizability and Selection Rules ............................................................ 44 1.7.2 Isotropic Spectra and Reduced Isotropic Spectra ..................................... 48 1.7.3 Raman Spectra of Aqueous Solutions....................................................... 52 1.8 Objectives of Thesis.......................................................................................... 53 2.0 EXPERIMENTAL METHODS............................................................................54 2.1 D2O Handling and Isotopic Purity .................................................................... 54 2.2 Chemicals and Solution Preparation................................................................. 54 2.2.1 Bisulfate System....................................................................................... 54 2.2.2 Phosphate System ..................................................................................... 55 2.2.3 Boric Acid System.................................................................................... 56 2.3 Instrumentation ................................................................................................. 56 2.3.1 Raman Spectrometer................................................................................. 56 2.3.2 Temperature Controllers........................................................................... 57 2.3.3 Data Treatment..........................................................................................59 3.0 DEUTERIUM ISOTOPE EFFECTS ON THE IONIZATION OF AQUEOUS BISULFATE FROM 25 °C TO 200 °C AT SATURATION PRESSURE ...... 6060 3.1 Introduction....................................................................................................... 60 3.2 Determination of the Second Ionization Constant for Sulfuric Acid, K2.......... 60 3.3 Experimental Methods..................................................................................... 61 3.4 Results..............................................................................................................
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