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Calorimetry of 4-Aminopyridine Alan Everett Av N Til Iowa State University

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Iowa State University Capstones, Theses and Retrospective Theses and Dissertations Dissertations 1976 Calorimetry of 4-aminopyridine Alan Everett aV n Til Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/rtd Part of the Analytical Chemistry Commons Recommended Citation Van Til, Alan Everett, "Calorimetry of 4-aminopyridine " (1976). Retrospective Theses and Dissertations. 6229. https://lib.dr.iastate.edu/rtd/6229 This Dissertation is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Retrospective Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. INFORMATION TO USERS This material was produced from a microfilm copy of the original document. 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Xerox University Microfilms 300 North Zeeb Road Ann Arbor, Michigan 48106 76-28,264 VAN TIL, Alan Everett, 1942- CALORIMETRY OF 4-AMINOPYRIDINE. Iowa State University, Ph.D., 1976 Chemistry, analytical Xerox University Microfilms, Ann Arbor, Michigan 48io6 ©Copyright by ALAN EVERETT VAN TIL 1976 Calorimetry of 4-amlnopyrldlne by Alan Everett Van Til A Dissertation Submitted to the Graduate Faculty in Partial Fulfillment of The Requirements for the Degree of DOCTOR OP PHILOSOPHY Department: Chemistry Major: Analytical Chemistry Approved: Signature was redacted for privacy. In Charge of Maj Work Signature was redacted for privacy. Fdr"the'Major Departm Signature was redacted for privacy. For the Gracfufete College Iowa State University Ames, Iowa 1976 Copyright Alan Everett Van Til, 1976. All rights reserved. 11 TABLE OF CONTENTS Page I. INTRODUCTION 1 II. LITERATURE REVIEW 3 A. Thermometrlc Tltrlraetry 3 B. Studies of 4-Amlnopyrldlne 3 III. THEORY OP CALORIMETRIC MEASUREMENTS 7 A. Steady-State Sensitivity of Electronic 7 Bridge Circuit 1. Temperature sensitivity of NTC and 7 PTC thermistors 2. Approximation to an ideal voltage 16 source for a resistive bridge circuit B. Dynamic Models for Heat Transfer 26 1. Thermistor probes in fully turbulent 26 flows 2. Temperature response of the stirred 55 fluid in a cylindrical calorimeter during electrical heating 3. An approximate solution to the 64 calorimeter equations a. Main period 64 b. Anterior period 74 c. Implementation of calculations 87 C. Pseudo-Isothermal Calorimetry 93 1. Requirements for a differential 93 operation 2. Magnitude of errors 98 Ill IV. INSTRUMENTATION 108 A. Thermistor Detector 108 B. Electronic Circuitry ill 1. Two-thermistor differential bridge ill 2. Voltage regulation 112 C. Differential Isoperlbol Calorimetry 112 1. Design 112 2. Construction 115 V. STEADY STATE AND DYNAMIC BEHAVIOR OP THERMISTORS 130 A. Experimental 130 1. Temperature sensitivity of NTC and 130 PTC thermistors 2. Thermistor time constant 132 3. Thermistor dissipation constant 134 4. Thermistor noise 134 B. Results and Discussion . 135 1. NTC thermistor material parameters 135 2. NTC, PTC, and NTC-PTC circuit 137 temperature sensitivity 3. Theoretical time constants 143 4. Theoretical dissipation constants 155 5. Theoretical thermistor noise 160 a. Power supply stability 160 b. Circuit noise 160 iv VI. STEADY-STATE AND DYNAMIC BEHAVIOR OF AN 166 ELECTRICALLY HEATED FLUID CALORIMETER A. Introduction 166 B. Experimental 166 1. Heat loss moduli 166 2. Heat capacity of reference cell 16? 3. Time constant of solution mixing 169 4. Time constant of calorimeter system 169 5. Balance of cell heat capacities 171 6. Experimental procedures 172 a. Energy measurement 172 b. Time measurement 172 C. Results and Discussion 173 1. Characteristics of calorimeter cells 173 a. Heat loss moduli 173 b. Heat capacities 176 2. Energy and time measurement 180 3. Implementation of the theoretically l8l derived calorimeter model 4. Time constant dependence on calorimeter 216 cell operating parameters 5. Optimization of calorlmetry system 220 response VII. STANDARD CHEMICAL SYSTEMS FOR CALORIMETRY 224 A. Heat of Solution of KCl(s) 224 1. History 224 V 2. Experimental 225 a. Preparation of KCl(s) 225 b. Injection of KCl(s) Into H^O 226 3. Results and discussion 228 B. Heat of Neutralization for Reaction of 230 NaOH(aq) and HClO^(aq) 1. History 230 2. Experimental 230 a. Preparation of solution 230 b. Standardization of solutions 232 c. Thermometric titration of 234 NaOH(aq) with HClO^ 3. Results and discussion 239 VIII. INVESTIGATION OF 4-AMINOPYRIDINE AS A 260 CALORIMETRIC STANDARD A. Introduction 260 B. Experimental 261 1. Purification of 4-amlnopyrldine(s) 261 2. Determination of purity of 263 4-aminopyridine(s) 3. Thermometric titration of 264 4-amlnopyrldine(aq) with HClO^(aq) 4. Preparation of 4-aminopyridine 264 perchlorate(s) 5. Spectral properties of 266 4-aminopyrldine(s) and 4-amlnopyrldlne perchlorate(s) 6. Thermal properties of 266 4-amlnopyrldine(s) and 4-amlnopyrldine perchlorate(s) vl C. Results and Discussion 26? 1. Purity and properties of 26? 4-aininopyridlne( s ) and 4-aminopyridlne perchlorate(s) 2. Heat of solution of 4-aininopyridine(s) 273 3. Heat of neutralization of 277 4-aminopyridine(aq) with HClO^(aq) 4. Heat of solution of 4-aininopyridine 287 perchlorate(s) IX. SUMMARY 295 X. SUGGESTIONS FOR FUTURE WORK 296 XI. BIBLIOGRAPHY 299 XII. ACKNOWLEDGEMENTS 312 XIII. APPENDIX A: LIST OF SYMBOLS 313 XIV. APPENDIX B: DERIVATION OF THERMISTOR 322 THERMAL CONDUCTIVITIES A. Transient Equivalent Conductivity 322 B. Steady-State Inner Conductivity 328 XV. APPENDIX C: DERIVATION OF BULK SOLUTION 331 HEATING RATE A. Main Period 331 B. Anterior Period 333 XVI. APPENDIX D: COMPUTER PROGRAM LISTINGS 337 A. Thermistor Time Constant, Dissipation 337 Constant, and Average Time Constant of Mixing B. Time Constant of Mixing 3^3 C. Approximate Temperature Response of the 348 Stirred Fluid in a Cylindrical Calorimeter During Electrical Heating vil LIST OF FIGURES Page Figure III.1. Circuit diagram of thermistor bridge 12 Figure III.2. Thevenin equivalent circuit of 21 thermistor bridge Figure IV.2. Thermistor probe 110 Figure IV .2. Voltage regulation circuit 114 Figure IV .3. Photograph of calorimeter 117 Figure IV,.H. Photograph of calorimeter probes 119 Figure IV,.5. Diagram of calorimeter head 121 Figure V,.1. Error curve for thermistor t^ v^ t^ 139 Figure V.,2. Temperature sensitivity of thermistors l42 Figure V.• 3. Time constant of t^ as a function of 149 Figure V.,4. NTC and PTC thermistor time constants 152 as a function of T Figure V. 5. Time constant of t, as a function of 154 i/ïb Figure V.6 . NTC and PTC thermistor dissipation 157 constants as a function of N„s Figure V.7. Temperature ratio of thermistor tj 159 as a function of time for electrical and environmental heating Figure VI.1. Heat loss modulus of calorimeter dewar 175 Figure VI. 2. Experimental and theoretical time 183 constants of mixing in the calorimeter cells as a function of N; Figure VI.3. Theoretical voltage output of the 186 bridge circuit as a function of time Figure VI. 4. Experimental heating curves of 189 reference cell as a function of r^ vlll Figure VI. 5. Theoretical heating curves of the 191 reference cell as a function of r s Figure VI. 6. Experimental heating curves of the 193 reference cell as a function of N s Figure VI. 7. Theoretical heating curve of the 195 reference cell as a function of N s Figure VI. 8. Theoretical heating curves of the 198 reference cell with toluene as the bulk solvent as a function of N s Figure VI. 9 • Theoretical heating rate of the 200 reference cell as a function of Figure VI.10. Theoretical bulk solution temperature 202 as a function of N s Figure VI.11. Theoretical excess temperature of bulk 204 solution at the thermistor position as a function of N s Figure VI.12. Theoretical temperature difference 207 across thermistor thermal boundary layer and thermistor bead as a function of N s Figure VI.13. Calculated Reynolds numbers for the 209 bulk solution and thermistor as a function of Figure VI.l4.
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