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I. SYNTHESIS AND THERMAL CHARACTERISTICS OF POLYACRYLONITRILE MODELS II. REACTIONS OF POTASSIUM CYANIDE SOLUBILIZED IN APROTIC SOLVENTS BY 18-CROWN-6 MACROCYCLIC POLYETHER, CRYSTALLINE COMPLEXES OF 18-CROWN-6 WITH VARIOUS NITRILE COMPOUNDS, AND SYNTHESIS OF 12-CROWN-4 A THESIS Presented to The Faculty of the Division of Graduate Studies and Research By Fred Leon Cook In Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the School of Chemistry Georgia Institute of Technology April, 1975 Copyright, 1975 by Fred Leon Cook I. SYNTHESIS AND THERMAL CHARACTERISTICS OF POLYACRYLONITRILE MODELS II. REACTIONS OF POTASSIUM CYANIDE SOLUBILIZED IN APROTIC SOLVENTS BY 18-CROWN-6 MACROCYCLIC POLYETHER, CRYSTALLINE COMPLEXES OF 18-CROWN-6 WITH VARIOUS NITRILE COMPOUNDS, AND SYNTHESIS OF 12-CROWN-4 Approved: C. L. Liotta, Chairman 71 ► A - E. M. Burgess I •••■••■4111 L. Zalkow Date approved by Chairman:4/14/75 ii ACKNOWLEDGMENTS The author wishes to express his appreciation to his research director, colleague, and friend, Dr. Charles L. Liotta, for guidance through these many research problems and for his unlimited enthusiasm and encouragement. Drs. E. M. Burgess and L. H. Zalkow are gratefully . thanked for reading and critically evaluating this manuscript. Numerous useful discussions of the work contained herein with Drs. E. M. Burgess, E. J. Grovenstein, and W. C. Tincher are also gratefully acknowledged. Special thanks are due Dr. W. C. Tincher for assistance in obtaining and interpreting the DTA/TGA data contained herein. A number of undergraduates participated in this work, and their assistance is appreciated by the author. C. W. Bowers and M. P. Byrne deserve special recognition for their contributions. The author's coworkers, H. P. Harris and T. R. Henson, are also acknowledged for stimulating discussions and cooperative ventures. The School of Textile Engineering of the Georgia Institute of Technology is thanked for the Tennessee Eastman Fellowship provided for the first 3 years of this work, and the School of Chemistry is likewise acknowledged for the DuPont Fellowship awarded for the last quarter of graduate study. iii Finally, heart-felt thanks are expressed to the author's wife, Patsy, whose infinite patience during the past few difficult years culminated in this thesis. Grate- ful recognition is also extended to the parents, family, and parents-in-law of the author for their encouragement, help, and financial support. iv TABLE OF CONTENTS Page ACKNOWLEDGMENTS ii LIST OF TABLES vii LIST OF ILLUSTRATIONS ix SUMMARY, POLYACRYLONITRILE MODELS xi SUMMARY, CROWN ETHERS xiii Chapter I. INTRODUCTION, POLYACRYLONITRILE MODELS . • • 1 Historical Background, Degradation and Models of PAN Degradation of PAN and Related Polymers Models of Polyacrylonitrile Syntheses of PAN Models, Related Chemistry Purpose of Research II. EXPERIMENTAL, POLYACRYLONITRILE MODELS . • • • 59 Instrumentation and Apparatus Chemicals Syntheses of Polyacrylonitrile Models DTA/TGA Analyses of PAN and its Models 13 C-NMR Analyses of PAN Models Syntheses of PAN Models, Related Chemistry III. RESULTS AND DISCUSSION, POLYACRYLONITRILE MODELS 111 Syntheses of PAN Models DTA/TGA Analyses of PAN and its Models 13 C-NMR Analyses of PAN Models Syntheses of PAN Models, Related Chemistry IV. CONCLUSIONS, POLYACRYLONITRILE MODELS 160 Syntheses of PAN Models DTA/TGA Analyses of PAN and its Models 13 C-NMR Analyses of PAN Models Syntheses of PAN Models, Related Chemistry V TABLE OF CONTENTS (Continued) Page V. RECOMMENDATIONS, POLYACRYLONITRILE MODELS . 166 Syntheses of PAN Models QTA/TGA Analyses of PAN Models I 3 C-NMR Analyses of PAN Models Syntheses of PAN Models, Related Chemistry VI. INTRODUCTION, CROWN ETHERS 170 Historical Background, Cationic Complexing Agents Syntheses of Crown Ethers Crown Ether Complexes Syntheses and Kinetics with Crown Ethers Nitrile Syntheses without Crown Ethers Purpose of Research VII. EXPERIMENTAL, CROWN ETHERS 213 Instrumentation Chemicals Safety Considerations Syntheses of Crown Ethers Complexes of 18-Crown-6 with Nitrile Compounds Reactions Utilizing "Naked" Cyanide Kinetic Studies with "Naked" Cyanide VIII. RESULTS AND DISCUSSION, CROWN ETHERS 277 Syntheses of Crown Ethers Complexes of 18-Crown-6 with Nitrile Compounds Reactions Utilizing "Naked" Cyanide Kinetic Studies with "Naked" Cyanide IX. CONCLUSIONS, CROWN ETHERS 329 Syntheses of Crown Ethers Complexes of 18-Crown-6 with Nitrile Compounds Reactions Utilizing "Naked" Cyanide Kinetic Studies with "Naked" Cyanide X. RECOMMENDATIONS, CROWN ETHERS 337 Syntheses of Crown Ethers Complexes of 18-Crown-6 with Nitrile Compounds Reactions Utilizing "Naked" Cyanide Kinetic Studies with "Naked" Cyanide vi TABLE OF CONTENTS (Continued) Page BIBLIOGRAPHY, POLYACRYLONITRILE MODELS 340 BIBLIOGRAPHY, CROWN ETHERS 362 APPENDICES 389 VITA 403 vii LIST OF TABLES Table Page 1. DTA/TGA Characteristics of Pure 1,3,5-Tricyano- pentance and Pure 2,4,6-Tricyanoheptane in Dry Air and Dry Nitrogen 131 2. DTA/TGA Characteristics of Polyacrylonitrile and Impure 2,4,6,8-Tetracyanononane in Dry Air and Dry Nitrogen 132 3. 13 C-NMR Absorptions of 1,3,5-Tricyanopentane, 2,4,6-Tricyanoheptane, and Related Compounds in PPM from TMS 140 4. Results Obtained from the Decarbalkoxylation of Reactive Esters in the Absence of Sodium Chloride, and Comparison with Literature Re- sults in the Presence of Sodium Chloride 148 5. Syntheses of Azines from Carbonyl Derivatives • • 155 6. Melting Points and 1H-NMR Analyses of 18-Crown- 6-Nitrile Complexes 286 7. Elemental Analyses of Selected 18-Crown-6- Nitrile Complexes 288 8. DTA/TGA Results for Selected 18-Crown-6- Nitrile Complexes 294 9. High-Resolution Infrared Analyses of Selected 18-Crown-6-Nitrile Complexes 296 10. 13C-NMR Analyses of Selected 18-Crown-6-Nitrile Complexes 297 11. Total Displacement of Primary Halides by "Naked" Cyanide in the Presence of 18-Crown-6 302 12. Products from the Incomplete Displacement of Primary Dihalides by "Naked" Cyanide in the Presence of 18-Crown-6 310 13. Products Obtained from the Reaction of cis-, trans-1,4-Dichloro-2-Butene with "Naked w anide in the Presence of 18-Crown-6 314 viii LIST OF TABLES (Continued) Table Page 14. Substitution and Elimination Reactions of Secondary Halides with "Naked" Cyanide in the Presence of 18-Crown-6 315 15. Addition Reactions Performed with "Naked" Cyanide in the Presence of 18-Crown-6 318 16. Reactions with "Naked" Cyanide in the Presence of 18-Crown-6 in which no Desired Product was Produced 322 17. Attempted Decarbalkoxylations with "Naked" Anions in the Presence of 18-Crown-6 324 ix LIST OF ILLUSTRATIONS Figure Page 1. Flow Diagram of the Developed Syntheses of 2,4,6-Tricyanoheptane and 2,4,6,8-Tetra- cyanononane 112 2. Flow Diagram of the Developed Synthesis of 1,3,5-Tricyanopentane 113 3. Flow Diagram of the Takata-Taniyama Syntheses of 2,4,6-Tricyanoheptane and 2,4,6,8-Tetra- cyanononane 114 4. Flow Diagram of the Zahn-Schafer Synthesis of 1,3,5-Tricyanopentane 115 5. Possible Chloride-Catalyzed Reverse Michael Addition of PAN Models 121 6. Possible Stereoisomers Produced in the Syn- thesis of 2,4,6-Tricyanoheptane 143 7. Proposed Mechanism for the Decarbalkoxylation of Reactive Esters in Wet Dimethyl Sulfoxide in the Absence of Sodium Chloride 150 8. Proposed Mechanism for the Decarbalkoxylation of Ethyl Phenylmalonate in Dry Dimethyl Sulfoxide in the Absence of Sodium Salts 153 9. Proposed Mechanism for the Formation of Azines from Hydrazones in Non-anhydrous Dimethyl Sul- foxide 157 10 Formation of Free Hydrazone Anion from Semi- carbazones in Wet Dimethyl Sulfoxide 158 11. Flow Diagram for the Synthesis and Purification of 18-Crown-6 278 12. Flow Diagram of the Developed Synthesis of 12- Crown-4 282 13. Relationship between the Melting Points of 18-Crown-6-Dinitrile Complexes, the Number of Methylene Units in the Dinitriles, and the Stoi- chiometries of the Complexes 290 x LIST OF ILLUSTRATIONS (Continued) Figure Page 14. GLC Monitor Diagram for the Reaction of 1,3- Dibromopropane with "Naked" Cyanide in CH 3 CN at Ambient Temperature 300 15. Equilibria Involved in the 18-Crown-6-Catalyzed Reaction of "Naked" Cyanide with Alkyl Halides . 307 16. Possible Mechanisms for the Formation of Prod- ucts Observed in the Reaction of "Naked" Cyanide with cis-, trans-1,4-Dichloro-2-Butene 313 17. Reversal of Cyclohexanone Cyanohydrin to Cyclo- hexanone by Catalytic Cyanide Ion Attack 321 18. Second-Order Kinetic Plot of the Reaction of 1- Chlorohexane with "Naked" Cyanide under Homoge- neous Conditions 327 x i SUMMARY, POLYACRYLONITRILE MODELS In the first portion of the thesis work, novel syn- theses of the pure 3-unit models of polyacrylonitrile (PAN), 1,3,5-tricyanopentane and 2,4,6-tricyanoheptane, and of the impure 4-unit model, 2,4,6,8-tetracyanononane, were developed. The syntheses were simpler, milder, and resulted in higher overall yields than older methods. Main difficulties encoun- tered in the devised procedures were lowered yields of model due to reverse Michael addition product formation, and puri- fication of the crude 4-unit model. Differential thermal analyses/thermal gravimetric analyses (DTA/TGA) of the pure 3-unit models, impure 4-unit model, and PAN itself were made in an attempt to elucidate and correlate the thermal degradative mechanisms. The pure 3- unit models were found to be inadequate for comparison tests with the thermal characteristics of the polymer, exhibiting little nitrile cyclization and catastrophic weight loss in the 200-300 0C region. The DTA/TGA curves of the 3-unit mod- els were independent of the atmosphere employed. The PAN examined behaved similarly to polymers reported in the litera- ture. The impure 4-unit model exhibited thermal character- istics similar to both the 3-unit models and PAN, but re- sembled the latter more than the former. On the basis of the results, self-initiation mechanisms for the nitrile cyclization were rejected in favor of initiation by impurity functional xii groups.

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