Organofluorine Chemistry Principles and Commercial Applications
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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.