Organofluorine Chemistry Principles and Commercial Applications

Edited by R. E. Banks The University of Manchester Institute ofScience and Technology (UMIST% Manchester, United Kingdom

B. E. Smart DuPont Central Research & Development Wilmington, Delaware

and J. C Tatlow Editorial Office of the Journal of Fluorine Chemistry Birmingham, United Kingdom

Plenum Press • New York and London Contents

1. Organofluorine Chemistry: Nomenclature and Histoncal Landmarks R. E. Banks and J. C. Tatlow 1.1. Preamble 1 1.2. Nomenclature 2 1.2.1. Highly Fluorinated Compounds 2 1.2.2. Fluorocarbon Code Numbers 4 1.3. Historical Landmarks 5 1.3.1. The HF Problem 5 1.3.2. Synthesis ofC—F Bonds 6 1.3.3. Aliphatic Fluorides GoCommercial 12 1.3.4. Perfluorocarbons 14 1.3.5. Wartime Advances: The Manhattan Project 17 1.3.6. Postwar Progress 17 1.4. References . . 21

2. Synthesis of Organofluorine Compounds R. E. Banks and J. C. Tatlow 2.1. Introduction 25 2.2. Synthesis Methodology 26 2.2.1. The Building-Block Approach 27 2.2.2. The Formation of Carbon-Fluorine Bonds 27 2.3. The Current Position 29 2.4. Tabular Summary of Fluorination Methods and Reagents 29 2.5. References 53

xi xii Contents

3. Characteristics of C-F Systems Bruce E. Smart 3.1. Introduction 57 3.2. Physical Properties 58 3.2.1. General 58 3.2.2. Solvent Polarity 64 3.2.3. Lipophilicity 66 3.2.4. Acidity and Basicity 67 3.2.5. Hydrogen Bonding 69 3.3. Chemical Properties 70 3.3.1. Bond Strengths and Reactivity 70 3.3.2. Reactive Intermediates 74 3.3.3. Steric Effects 80 3.4. References 82

4. Perfluorocarbon Fluids 5. W. Green, D. S. L. Slinn, R. N. F. Simpson, andA. J. Woytek 4.1. Introduction 89 4.1.1. Perfluorocarbon Gases 89 4.1.2. Perfluorocarbon Liquids 90 4.2. Production of Perfluorocarbons 91 4.2.1. Processes for Perfluorocarbon Gases 91 4.2.2. Processes for Perfluorocarbon Liquids 92 4.3. Physical Properties 93 4.4. Applications of Perfluorocarbons 95 4.4.1. Perfluorocarbon Gases as Etchants 95 4.4.2. Perfluorocarbon Liquids as Alternatives to Chlorofluorocarbons ... 97 4.4.3. Perfluorocarbon Liquids as Heat Transfer Agents 104 4.4.4. Miscellaneous Applications of Perfluorocarbon Liquids 114 4.5. References 118

5. Electrochemical Fluorination and Its Applications Y. W. Ahmeyer, W. V. Childs, R. M. Flynn, G. G. I. Moore, and J. C. Smeltzer 5.1. Coverage 121 5.2. Simons Electrochemical Fluorination 121 5.2.1. Introduction 121 Contents xiii

5.2.2. Experimental Technique 122 5.2.3. Anode Film 123 5.2.4. Mechanisms 124 5.2.5. Scope 126 5.2.6. Commercial Utility of ECF-Derived Materials 129 5.3. Cave-Phillips Process for Electrochemical Fluorination 133 5.3.1. Systems 133 5.3.2. Feeds 135 5.3.3. Nonwetting Behavior 135 5.3.4. Polarization 137 5.3.5. Brief History of an Anode 138 5.3.6. Fluorination Results 138 5.3.7. SummaryoftheCAVEECF Process 140 5.4. References 140

6. Chlorofluorocarbons Arthur J. Elliott 6.1. Introduction 145 6.2. Production 147 6.2.1. Halogen Exchange 147 6.2.2. Chlorotrifluoroethylene Telomerization 149 6.3. Properties and Specifications 150 6.4. Applications 151 6.4.1. General 151 6.4.2. Declining Applications 151 6.4.3. Continuing Applications 153 6.5. References 156

7. Alternatives to Chlorofluorocarbons (CFCs) V. N. M. Rao 7.1. Introduction 159 7.2. Synthesis 162 7.2.1. 1,1,1, 2-Tetrafluoroethane>CF3CH2F(HFC-134a) 162 7.2.2. 2,2-Dichloro-l)l,l-trifluoroethane,CF3CHCl2 (HCFC-123) 165 7.2.3. 2-Chloro-l,l,l,2-tetrafluoroethane,CF3CHFCl (HCFC-124) .... 167 7.2.4. Pentafluoroethane,CF3CHF2(HFC-125) 168 7.2.5. 1,1-Dichloro-l-fluoroethane, CFCl2CH3(HCFC-141b) 169 7.2.6. l,l-Difluoroethane,CHF2CH3(HFC-152a) 169 xiv Contents

7.2.7. Dichloropentafluoropropanes 170 7.3. Commercial Aspects 171 7.4. Properties 171 7.5. Applications 172 7.5.1. Refrigeration 172 7.5.2. Foaming Agents 172 7.5.3. Solvents 173 7.6. References 173

8. Perfluoroalkyl Bromides and Iodides Claude Wakselman and Andre Lantz 8.1. Introduction 177 8.2. Preparation 178 8.3. Reactions 178 8.3.1. "Classical" Radical Reactions 178 8.3.2. Reactions with Nucleophiles 180 8.3.3. Reactions with Metals 183 8.3.4. Reactions with Acidic Reagents 184 8.3.5. Electrochemical Transformations 185 8.4. Applications 185 8.4.1. Halons 185 8.4.2. Perfluoroalkyl Iodides 188 8.5. References 190

9. Industrial Routes to Ring-FIuorinated Aromatic Compounds J. S. Moilliet 9.1. Introduction 195 9.2. "Halex" Fluorinations 196 9.2.1. General Considerations 196 9.2.2. Examples 198 9.2.3. Fluoride Sources 199 9.2.4. Solvents 200 9.2.5. Procedura for the Halex Process 201 9.3. Diazotization Methods 203 9.3.1. The Balz-Schiemann Reaction 203 9.3.2. HF-Diazotization/Dediazoniation 207 9.4. Other Fluorination Methods 211 Contents XV

9.4.1. Cobalt Fluoride Fluorination 211 9.4.2. Using Hydrogen Fluoride 212 9.4.3. Direct Fluorination 213 9.5. Comparison of the Three Principal Methods 213 9.6. The Industrial Scene 214 9.6.1. HF-Diazotization/Dediazoniation 214 9.6.2. Halex Fluorination 217 9.6.3. Balz-Schiemann Methodology 217 9.7. Concluding Remarks 217 9.8. References 218

10. Side-Chain Fluorinated Aromatic Compounds Routes to Benzotrifluorides

Bernard Langlois 10.1. Introduction 221 10.2. Synthesis of Benzotrifluorides from the Corresponding Toluenes: Liquid-Phase Methods 222 10.2.1. General Considerations 222 10.2.2. Fluorination of Benzotrichlorides 224 10.3. Vapor-Phase Routes to Benzotrifluorides and (Trifluoromethyl)pyridines 225 10.4. Synthetic Manipulation of Benzotrifluorides 225 10.4.1. Electrophilic Substitution 225 10.4.2. Nucleophilic Displacement of Nuclear Halogen from 4-Halogenobenzotrifluorides 227 10.4.3. HydrolysisofTrifluoromethylGroups 228 10.5. Newer Commercially Interesting Methods for the Trifluoromethylation of Aromatic Compounds 229 10.5.1. Electrophilic Trifluoromethylation 229 10.5.2. "Nucleophilic" Trifluoromethylation 230 10.5.3. Radical Trifluoromethylation 230 10.6. Concluding Remarks 232 10.7. References 232

11. Recent Developments in Fluorine-Containing Agrochemicals

David Cartwright 11.1. Introduction 237 11.2. Occurrenceof Fluorine in Agrochemicals 239 xvi Contents

11.3. Fluorine-Containing Herbicides 240 11.3.1. Herbicides Containing an Aromatic-Type CF3 Group 240 11.3.2. Herbicides Containing a Fluoroaromatic Group: Pyridyloxyacetic Acids 244 11.3.3. Herbicides Containing a Fluoroalkoxy Group: Sulfonylureas 245 11.3.4. Herbicides Containing a Trifluoromethanelsulfonyl Group: Trifluoromethanesulfoanilides 245 11.4. Fluorine-Containing Insecticides 246 11.4.1. Compounds Affecting Insect Growth 246 11.4.2. Pyrethroid Insecticides 247 11.4.3. Others 252 11.5. Fluorine-Containing Fungicides 252 11.5.1. Sterol Biosynthesis Inhibitors 252 11.5.2. Amide Fungicides 255 11.6. Fluorine-Containing Plant Growth Regulators 255 11.6.1. Compounds that Interfere with Gibberellin Biosynthesis 255 11.6.2. Benzylamine Derivatives 256 11.7. Rodenticides 257 11.8. References 257

12. Fluorinated Liquid Crystals Takeshi Inoi 12.1.Introduction 263 12.2. Properties and Structural Classification of Liquid Crystals 263 12.3. Applications 267 12.4. Molecular Design 267 12.5. Fluorinated Liquid Crystals 270 12.5.1. Semifluorinated Alkanes 271 12.5.2. Schiff Bases (Azomethines) .271 12.5.3. Benzoates 271 12.5.4. Biphenyls 275 12.5.5. Cyclohexanecarboxylates 276 12.5.6. Liquid Crystals with Hybridized Structures and Multiring Systems 276 12.6. Ferroelectric Liquid Crystals 283 12.7. Conclusions 284 12.8. References 285 Contents xvii

13. Fluorine-Containing Dyes A. Reactive Dyes K. J. Herd 13A.l.Introduction 287 13A.2. Dyestuffs with One Reactive System 288 13 A.2.1. General Informationen Reactive Dyes 288 13A.2.2. Heterocyclic Carrier Systems with Fluorine as the Leaving Group 289 13A.2.3. Preparation of the Reactive Compounds 297 13A.2.4. Preparation of the Reactive Dyes 299 13A.3. Dyes with Two or More Reactive Systems 302 13A.3.1. Homobifunctional Reactive Dyes 303 13A.3.2. Heterobifunctional Reactive Dyes 303 13A.3.3. Polyfunctional Reactive Dyes 306 13A.4. Conclusion 307 13A.5. References 307

13.B. Other Fluorinated Dyestuffs A. Engel 13B.l.Introduction 315 13B.2. Properties of Fluorine-Containing Dyes 315 13B.3. Summary and Outlook 320 13B.4. References 320

14. Textile Finishes and Fluorosurfactants Nandakumar S. Rao and Bruce E. Baker 14.1. Textile Repellent Finishes 321 14.1.1. Intrinsic Repellency and Fluorocarbon Structure 321 14.1.2. Synthesis of Fluoroalkyl Intermediates 325 14.1.3. Synthesis of Fluorochemical Repellents 329 14.1.4. Soil-Release Finishes 331 14.1.5. Future Developments 332 14.1.6. Major Manufacturers 332 14.2. Fluorosurfactants 333 14.2.1. Fluorosurfactant Synthesis 333 14.2.2. Aqueous Solutions of Fluorosurfactants 334 xviii Contents

14.2.3. Properties and Uses 336 14.3. References 336

15. Fluoroplastics Andrew E. Feiring 15.1.Introduction 339 15.2. Fluorinated Vinyl Monomers 341 15.3. Crystalline Perfluoroplastics 342 15.3.1. Poly(tetrafluoroethylene) (PTFE) 342 15.3.2. Perfluorinated Copolymers (FEP and PFA) 344 15.3.3. Properties ofthe Perfluoroplastics 346 15.3.4. Applications and Commercial Aspects 348 15.4. Amorphous Perfluoroplastics 349 15.5. Poly(chlorotrifluoroethylene) 350 15.5.1. Production 351 15.5.2. Properties 351 15.5.3. Applications and Commercial Aspects 352 15.6. Partially Fluorinated Plastics 352 15.6.1. Ethylene-Tetrafluoroethylene Copolymer 352 15.6.2. Ethylene-Chlorotrifluoroethylene Copolymer 354 15.6.3. Poly(Vinylidene Fluoride) 356 15.6.4. Poly(Vinyl Fluoride) 358 15.7. Other Fluorine-Containing Plastics 360 15.7.1. Addition Polymers 360 15.7.2. Condensation Polymers 362 15.7.3. Surface-Fluorinated Plastics 363 15.8. Outlook and Conclusions 364 15.9. References 364

16. Fluoroelastomers Anestis L. Logothetis 16.1. Introduction 373 16.1.1. Chemical Compositions 374 16.1.2. Structural Considerations 374 16.2. Fluoroelastomers Based On Vinylidene Fluoride Copolymers 376 16.2.1. General Description 376 16.2.2. Production 377 Contents xix

16.2.3. Curing (Vulcanization) of Fluoroelastomers Containing Vinylidene Fluoride 380 16.2.4. Properties 383 16.2.5. Processing 385 16.3. Fluoroelastomers Based on Tetrafluoroethylene/Propylene Copolymers 387 16.3.1. Introduction 387 16.3.2. Polymerizations 387 16.3.3. Curing Chemistry and Properties 388 16.3.4. Processing 388 16.4. Perfluoroelastomers Based on Tetrafluoroethylene/Perfluoro(alkyl vinyl ether) Copolymers 389 16.4.1. Polymer Description 389 16.4.2. Polymerizations 390 16.4.3. Curing Chemistry 390 16.4.4. Properties 392 16.4.5. Processing 393 16.5. Usesof Fluorinated Elastomers 393 16.6. References 394 16.6.1. General References 394 16.6.2. Specific References 394

17. Fluoropolymer Coatings Masaaki Yamabe 17.1. Introduction 397 17.2. Thermoplastic Fluoropolymer Coatings 397 17.2.1. Tetrafluoroethylene Polymers 397 17.2.2. Poly(Vinylidene Fluoride) 398 17.3. Curable Fluoropolymer Coatings 399 17.4. References 401

18. Fluorinated Membranes Masaaki Yamabe and Haruhisa Miyake 18.1. Introduction 403 18.2. Structure and Properties 404 18.3. Preparation 405 18.4. Applications 407 18.4.1. Chlor-Alkali Process 407 18.4.2. Outlook 409 18.5. References 410 XX Contents

19. Monomers and Polymers from Hexafluoroacetone Wolf gang K. Appel, Bernd A. Blech, and Michael Stöbbe 19.1.Introduction 413 19.2. Synthesis of Hexafluoroacetone (HFA) 413 19.3. Synthesis of Intermediates Containing the Hexafluoroisopropylidene Group 414 19.3.1. The Overall Reaction Sequence 414 19.3.2. Formation of Arylbis(trifluoromethyl)carbinols 414 19.3.3. Propertiesof Arylbis(trifluoromethyl)carbinols 417 19.3.4. Formation of Diphenylhexafluoropropanes 418 19.4. Directly Accessible HFIP-Bridged Monomers and Intermediates 419 19.5. Polymers Containing Hexafluoroisopropylidene Groups 421 19.5.1. Aromatic 6F-Polyesters 421 19.5.2. Aromatic 6F-Polyamides 422 19.5.3. Aromatic 6F-Polyimides 423 19.6. Conclusion 427 19.7. References 427

20. Perfluoropolyethers (PFPEs) from Perfluoroolefin Photooxidation: Fomblin® and Galden® Fluids Dario Sianesi, Guiseppe Marchionni, and Ralph J. De Pasquale 20.1. Introduction 431 20.2. The Photooxidation Route to Neutral PFPEs 432 20.2.1. Oxidative Photopolymerization of Fluoroolefins 432 20.2.2. Removal of Peroxide Linkages 435 20.2.3. End-Group Modification to Give Neutral PFPEs 437 20.3. Mechanism ofHFP and TFE Oxidative Photopolymerization 438 20.4. Chemical and Physical Properties of Fomblin® and Galden® Fluids 440 20.4.1. Chemical Properties and Solubilities 440 20.4.2. Thermal Properties—Influenceof Metals 442 20.4.3. Oxidative Stability, Radiation Resistance, and Bioinertness .... 443 20.4.4. Physical Properties 443 20.4.5. Greases 446 20.4.6. Tribology 446 20.4.7. Rheology 448 20.5. Functional PFPEs from Photooxidation 450 20.6. Applications of PFPEs 453 20.6.1. Testingof Electronic Devices and Equipment 453 20.6.2. Polymer Curing . 454 20.6.3. Lubrication 454 Contents xxi

20.6.4. Surfactants, Emulsions, and Cosmetics 454 20.6.5. Polymer Modification 455 20.6.6. Conductive Films 455 20.6.7. Mass Spectrometry 455 20.6.8. Environmental Applications 456 20.7. Future Prospects 456 20.8. References 457

21. Perfluoropolyether Fluids (Demnum®) Based on Oxetanes Yohnosuke Ohsaka 21.1.Introduction 463 21.2. Preparation 463 21.2.1. Monomers 463 21.2.2. Oligomers 464 21.3. Properties 464 21.3.1. General 464 21.3.2. Toxicity 465 21.3.3. Comparative PFPE Properties 465 21.4. Applications 466 21.4.1. Base Oil for Greases 466 21.4.2. Semiconductor Manufacturing 466 21.4.3. Miscellaneous 467 21.5. References 467

22. Surface Fluorination of Polymers Madhu Anand, J. P. Hobbs, and lan J. Brass 22.1.Introduction 469 22.2. Reactions ofElemental Fluorine with Organic Polymers 469 22.3. Properties and Applications of Surface-Fluorinated Polymers 471 22.3.1. Barrier Properties 471 22.3.2. Adhesion and Surface Energy 473 22.3.3. Other Properties of Fluorinated Surfaces 474 22.4. Techniques for the Direct Fluorination of Polymer Surfaces 475 22.4.1. Post-Treatment 475 22.4.2. In Situ Treatment . 477 22.5. Safety and Environmental Concerns 478 22.6. Conclusions 479 22.7. References 479 xxii Contents

23. Fluorinated Carbon George A. Skia and Ganpat Moni 23.1.Introduction 483 23.2. Physical Properties 484 23.3. Chemical Properties 488 23.4. Manufacture 489 23.5. Applications 490 23.5.1. Batteries 490 23.5.2. Lubrication 492 23.5.3. Imaging 494 23.6. Fluorine Intercalation Compounds of Graphite 495 23.7. Health/Safety 495 23.7.1. Toxicity 495 23.7.2. Dermal and Ocular Effects 496 23.7.3. Cytotoxicity 496 23.7.4. Handlingof Fluorinated Carbons 496 23.8. References 496

24. Uses of Fluorine in Chemotherapy Philip Neil Edwards 24.1. General Introduction 501 24.2. Fluoroquinolone Antibacterial Agents 502 24.2.1. Introduction 502 24.2.2. Early 6-Fluoro-7-piperazino-quinolones 503 24.2.3. Mode ofAction 505 24.2.4. New Structural Types 506 24.3. Electronegativity and Its Consequences 509 24.3.1. What Is Electronegativity and Can "If'Be Quantified? 509 24.4. Dipole Moments and Electron Density Distributions in Halogeno Compounds 511 24.5. Fluorine Substitution in Acid-Sensitive Compounds 512 24.6. Hydrogen Bonding in Fluoro Compounds 514 24.6.1. Fluorine as Hydrogen-Bond Acceptor 515 24.6.2. Halogeno-Substituent Effects on Hydrogen-Bond Donor and Acceptor Ability 520 24.7. Fluoroketone Enzyme Inhibitors 525 24.8. Inhibition of Pyridoxal-Dependent Enzymes 527 24.9. Drug Absorption and Distribution 530 24.9.1. Fluorine Substitution in Relation to log Poctanoi Values 531 Contents xxiii

24.9.2. Solubility Effects 532 24.10. Fluorination Effects on Metabolism and Elimination 533 24.11. The Size and Shape of Fluoro Substituents 536 24.12. References 539

25. Fluorinated Inhalation Anesthetics Donald F. Holpern 25.1. Introduction 543 25.2. The Fluorine Revolution 544 25.2.1. Halothane 546 25.2.2. Methoxyflurane 546 25.2.3. Enflurane 547 25.2.4. Isoflurane 547 25.2.5. Sevoflurane 550 25.2.6. Desflurane 551 25.3. Conclusions and Acknowledgments 552 25.4. References 553

26. Properties and Biomedical Applications of Perfluorochemicals and Their Emulsions Kenneth C. Lowe 26.1. Introduction 555 26.2. Properties ofPFCs 556 26.3. Synthesis of PFCs 558 26.4.EmulsificationofPFCs 558 26.4.1. "First-Generation" Emulsions 558 26.4.2. Improved Emulsions 560 26.4.3. Surfactants 561 26.5. Biocompatibility Assessment 562 26.5.1. TissueUptake and Excretion 563 26.5.2. Effects on Lymphoid Tissues and the Reticuloendotheiial System 563 26.5.3. Effects on Immunological Competence 563 26.5.4. Effects on Tissue Biochemistry 565 26.5.5. Other in vivo Responses 565 26.5.6. Cellular Effects in vitro 566 26.5.7. Effects of Surfactant(s) 567 26.6. Biomedical Applications 568 xxiv Contents

26.6.1. Microcirculatory Support in Ischemic Tissues 568 26.6.2. Coronary Angioplasty 569 26.6.3. Cancer Therapy 570 26.6.4. Contrast Media and Diagnostic Imaging 570 26.6.5. Respiratory Distress Syndrome 570 26.6.6. Decompression Sickness 571 26.6.7. Lung Damage and Respiratory Failure 571 26.6.8. Blood Diseases 572 26.6.9. Applications in Ophthalmology 572 26.6.10. Organ Perfusion and Preservation 572 26.6.11. Cell Culture Studies 572 26.7. Concluding Remarks 573 26.8. References 573

27. The Fluorochemical Industry A. The Fluorochemical Industry in the United States Richard A. DuBoisson 27A.1. The Manufacture of Hydrogen Fluoride in the United States 579 27A. 1.1. Industrial Preparation of Hydrogen Fluoride 579 27A.1.2. U.S. Manufacturers of Hydrogen Fluoride 580 27A. 1.3. Hydrogen Fluoride Production Statistics 580 27A.2. Industrial Uses of Hydrogen Fluoride 582 27A.2.1. Introduction 582 27A.2.2. Chlorofluorocarbons and Related Halogenoalkanes 583 27A.2.3. Aluminum Production 590 27 A.2.4. Petroleum Alkylation 590 27A.2.5. Aqueous Hydrofluoric Acid 591 27A.2.6. Fluorine 591 27A.2.7. Uranium 591 27A.2.8. Chemical Intermediates 592 27A.3. References 592 27. B. Organofluorine Products and Companies in Western Europe Peter Field 27B.1. Introduction 595 27B.2. Fluoroaliphatics 595 27B.2.1.Fluorocarbons 595 27B.2.2. Halogenofluorocarbons 596 27B.2.3. Trifluoroacetic Acid and Its Derivatives 597 27B.2.4. Trifluoromethanesulfonic Acid and Its Derivatives 598 Contents XXV

27B.2.5. Higher (>C2) Fluoroalkane Derivatives 599 27B.3. Fluoroaromatics 600 27B.3.1. General Comments 600 27B.3.2. Nuclear-Fluorinated Aromatics 601 27B.3.3. Production of Nuclear-Fluorinated Aromatics in Europe . . . . 604 27B.3.4. Side-Chain Fluorinated Aromatics 605 27B.4. Fluoropolymers 607 27B.5. Note Added in Proof: Developments Concerning Companies 607 27B.6. References 608

27.C. Manufacturers of Organic Fluoro Compounds in Japan 609

Nobuo Ishikawa

28. CFCs and the Environment: Further Observations

Richard L. Powell and J. Hugo Steven 28.1.Introduction 617 28.2. Refrigeration 618 28.3. The Ozone Layer Problem 621 28.4. Replacements for the Chlorofluorocarbons 622 28.5. Discovery ofAntarctic Ozone Depletion 624 28.6 The Montreal Protocol 625 28.7. Replacements for the Chlorofluorocarbons: A Second Look 626 28.8. Commercial Production of Chlorofluorocarbon Replacements: The Third Period of Refrigeration 629 28.9. References 629

Index 631