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Thermodynamics of Proton Ionization in Aqueous Solution I

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Thermodynamics of Proton Ionization in Aqueous Solution I Brigham Young University BYU ScholarsArchive Theses and Dissertations 1965-08-01 Thermodynamics of proton ionization in aqueous solution I. A precision thermometric titration calorimeter ; II. Entropy titration : a calorimetric method for equilibrium constant determinations ; III. H and S values for carboxylic acid proton ionization at 25C ; IV. Site of proton ionization from adenosine Lee D. Hansen Brigham Young University - Provo Follow this and additional works at: https://scholarsarchive.byu.edu/etd BYU ScholarsArchive Citation Hansen, Lee D., "Thermodynamics of proton ionization in aqueous solution I. A precision thermometric titration calorimeter ; II. Entropy titration : a calorimetric method for equilibrium constant determinations ; III. H and S values for carboxylic acid proton ionization at 25C ; IV. Site of proton ionization from adenosine" (1965). Theses and Dissertations. 8222. https://scholarsarchive.byu.edu/etd/8222 This Dissertation is brought to you for free and open access by BYU ScholarsArchive. It has been accepted for inclusion in Theses and Dissertations by an authorized administrator of BYU ScholarsArchive. For more information, please contact [email protected], [email protected]. (Yj) /, 02 2 _,J.30 { L"}/'.,C: l ,t:,:..-- THERMODYNAMICSOF PROTON IONIZATION IN .AQUEOUSSOLUTION I. A PRECISION THERMOMETRICTITRATION CALORIMETER II. ENTROPYTITRATION: A CALORIMETRICMETHOD ·:B'O'R EQUILIBRIUMCONSTANT DETERMINATIONS III. Lll° AND LS 0 VALUESFOR C.ARBOXILIC.ACID PROTONIONIZATION .AT 25°C IV. SITE OF PROTONIONIZATION FROM .ADENOSINE .A Dtssertation Presented to the Department of Chemistry Brigham Young University In Partial Ful.fillment of the Requirements for the Degree Doctor of Philosophy" by Lee Dwme Hansen August, 1:965 This dissertation by Lee Doane Hansen is accpeted in its present form by the Department of Chemistry of' Brigham Young University as satisfying the thesis requirements for the degree of Doctor of Philosophy. Typed by Judith W. Hansen ACKNOWLEDGEMENTS To Dr. Reed M. Izatt and Dr. James J. Christensen in equal measure~ the author gives special thanks and aclmowledges the maey hours above and beyond the call of duty which they spent in trying to civilize him. The author also wishes to thank Dr. C. L. Cluff~ Dr. J. Rex Goates~ and Dr. J. L. Bills tor their support and suggestions in the writing of this dissertation and for the excellent teaching received from them. The friendship of fellow graduate and undergraduate students is grateful.ly acknowledged by the author. For her help in preparing this dissertation and for mending :manyacid holes, the author thanks his wife, Judi. The a11.th.or also wishes to acknowledge the help of' his noisy children~ who often forced him to seek the peace and quiet of the lab. For instilling in him a desire to learn~ the author thanks his parentsi Alva and Mary Hansen~ and also Ard.th K. Huf'faar.-.r and Delos Gardner of his home town. Appreciation is expressed to the Department ot Healthi Ed.11.cation~ and Welfare for financial support through a National Defenee Edu... cation Act Fellowship. iii CONTENTS Page ACKNOWLEOOEMENTS••••••••••••••••••••••••••••••••••••••••••••••••• iii LIST OF TABLES••••••••••••••••••••••••••••••••••••••••••••••••••·viii LIST OF ILLUSTRATIONS............................................ :x: LISTOF PUBLICATIONS RESULTING FROM THIS DISSERTATION •••••••••••• xi GENERALINTRODUCTION............................................. 1 STUDYI. DESIGN,CONSTRUCTION, ANDCALIBRATION OF A PRECISIONTHERMOMETRIC TITRATION CALORIMETER............................................4 I. Irltroduction •• _., • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 4 II. Desi~ cttteria ••• ~ •• ~.•~•••••••••••••••••••••••••••••• 7 III. Description of Equipment••••••••••••••••••••••••••••••' 10 A. Details of Calorimeter Construction ••••••• '• • • • • • 10 B. Constant Temperature Baths•••••••••••••••••••••• 16 c. Buret and Titrant Cirouit •••• ~ •••••••••••••••••• 17 D. Temperature Measuring Circuit ••••••••••••••••••• 20 E. Heater C:lrcruit•••••• ~ ••••••••••••••••••••••••••• 22 F. Temperature Adjustment Circuit •••••••••••••••••• 22 IV. Calibration of Equipment••••••••••••••••••••••••••••••• 25 A. Apparent Heat Capacity•••••••••••••••••••••••••• 25 B. Thermistor Calibration •••••••••••••••••••••••••• 26 c. Calibration or Amplifier and Recorder ••••••••••• 27 iv Page v. Performance•••••••••••••••••••••••••••••••••••••••••••••• 27 A. General ••••••••••••••••••••••••••••••••••••••••••• 27 B. Circuit Noise Level•••••••••••••••••••••••••••••·• 28 c. Instrument Precision and Accuracy -The Heat of Ionization of H2o•••••••••••·••••••• 28 VI. Da."ta .An.al.ysis. • • • • . • • • . • . • . 29 'VII • SUJmn.aey.• • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 0 • • • • • • • • • J6 STUDYII. ENTROPYTITRATION••••••••••••••••••••••••••••••••••••••• 3? I. Introduction . ....••...........•••................. ~ . o •• " • J7 II. Theoey. • • . • • • • • • • • • • • • • • • • . • • • • • • • • • • • • • • • • • • • • • • • • • • • . • • 39 III. The Formation or HS04 from H"' and so4.................... 40 A. Calculations •••••••••••••••••••••••••••••••••••••• 4-0 B. Experimental •••••••••••••••••••••••••••••••••••••• 42 c. Results and Jli.scussion •••••••••••••••••••••••••••• 42 IV. The Reaction of HPO~ with OH·••••••••••••••••••••••••••• 47 A. Calculations •••••••••••••••••••••••••••••••••••••• 47 B. E'!:xpe:ri.mental• •••••••••••••••••••••••••••••••••• • • • c. ResuJ.ts •••••••• • ••••• .............................. v. The Reaction of Oh· with Adenosine and Ribose •••••••••••• .51 A. Cal.cuJ.ations • •••••••••.••••. • ••••..••••••••...••.. 51 B. E:xper:Lmental . ...................•..•.•............ 52 c. Results and Jli.scussion •••••••••••••••••••••••••••• 52 VI. Conclusions ••••••••••••••••••••••••••••••••••••••••••••.• 53 STUD7III. ENT?..ALPY ANDENTROPY CHANGES VliLID AT 2S,C and u = 0 FORIONIZATION OF PROTONS FROI-:~.tRBOXYLIC ACIDS nT AQUEOUSSOLUTION.............. 56 V Page I. Introduction .••••••••••••••••••••••••••••••••••••••.••••• 56 II. Calculations and Experimental •••••••••••••••••••••••••••• .58 m. Results •••••••••••••••••••••••••••••••••••••••••••••••••• 59 A. General ••••••••••••••••••••••••••••••••••••••••••• 59 B. Accuracy of Results •••• ~•••••••••••••••••••••••••• 59 IV. ntseussion and Conclusions ••••••••••••••••••••••••••••••• 71 A. Factors Affecting ~ HGand ~ s0 Values for Carbo:xylic Acid Proton Ionization in Aqueous Solution •••••••••••••••••••• 71 B. The Inductive Theory as Applied to Carbo:xylic Acids••••••••••••••••••••••••••••••• 74 c. The Linear T~s 0 , ~ HGRelationship as Applied to Carbo:xylic Acids•••••••••••••••••••• 77 D. The Kirkwood-Westheimer Electrostatic Theory as Applied to Carbo:xylic Acids••••••••••••• 78 E. The Linear Relation between ~G 0 and ~s 0 ••••••••• 80 F. Intramtlecular 1-{ydrogenBonding••••••••••••••••••• 84 STUDYIV. THESITE OF PROTONIONIZATION FROM ADENOSINE •••••••••••• 87 I. Introduction •• ~.~•••••••••••••••••••••••••·•••••••••••••• 87 II. Experimental ••••• ! .... ~ .................................. 88 m. Results •••••••••••••••••••••••••••••••••••••••••••••••••• 90 APPENDIXA••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 92 APPENDIXB••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 94 APPENDIXC••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 402 APPENDIXD••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 104 APPENDIXE•••••••••••••••••••••••••••••••••••••••••••••••••••••••~• 106 v.i. Page APPENDIXF•••••••••••••••••••••••••••••••••••••••••••••••••••••••• 124 .APPENDIXG•••••••••••••••••••••••••••••••••••••••••••••••••••••••• 140 APPENDIXH•••••••••••••••••••••••••••••••••••••••••••••••••••••••• 1,54 REF.ERENCES•••••••••••••••••••••••••••••••••••••••••••••••••••••••• 210 vii LIST OF TABLES Table Page 1 pK and 6H Values f'or Proton Ionization from HS04,•••• ••••••••••••••••••••••••••••••••••••••••••••• 2 Log K and 6H Values for:,.:he Reaction Oli + HPOf = H20 + P04 •••••••••••••••••••••••••••••••• 51 Log K and 6H Values for the Reaction HA+ Olr = A~+ H20••••••••••••••••••••••••••••••••••••• 4 pK Values f'or the Carbox,ylic Acids Used in This Study ••••••••••••••••••••••••••••••••••••••••••••• 6Q 5 Standard Free Energy, Enthalpy, and Entropy Changes for Dissociation of Protons from Carbox,ylic Acids in Aqueous Solution at 2,9-lC.ano.u.•.0•••••••••••••••••••••••••••••••• 62 6 Factors Affecting the Values of 6H9 and 6 s0 for Ionization of Protons from an Acid in Aqueous Solution.••••••••••••••••••••••••• 75 7 Values of (pK - pK ), ( 6~ - 6 !11), 2 1 0 (6S~ - 6S!), and {TL,S - T65i) for Selected Di.carbox,ylic A~d Ionizations•••••••••••••••••••• 85 8 Heat Leakage Moduli Data•••••••••••••••••••••••••••••••••• 93 9 Voltage Divider C.iibration Data•••••••••••••••••••••••••• 94 10 Apparent Heat Capacity of Calorimeters Exclusive of Contents•••••••••••••••••••••••• 98 11 Thermistor Calibration Data••••••••••••••••••••••••••••••• 102 12 The Enthalpy Change for Ionization of ffiO•••••••••••••••••••••••••••••••••••••••••••••••••••• 105 13 Log K and 6H Values Determined by the Entropy Titration Method for the Reaction ii++ so = H~ in Aqueous Solution 4at 25°C•••••••••••••••••••••••••••••••••• 106 viii Table Page 14 Materials•••••••••••••••••••••••••••••••••••••••••••••••• 123 15 Log K and 6H Values Determined by the Entropy Titrati~ MethodJ!o: the Reaction Oii + HP04 = P04 ..-r.H20in Aqueous Solution at 25°c•••••••••••••••••••••••••••••••••
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