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Dedicated to Professor Rolf Sammet on the occasion of his 65th birthdayOf the important C,-compounds in organofluorine chemistry, namely hexafluoropropene, hexafluoroacetone and hexafluoropropene oxide, the latter is chemically the most versatile compound. Hexafluoropropene oxide provides another example of the frequently observed change in reactivity when hydrocarbon compounds are converted into their perfluorinated derivatives. The overwhelming majority of the known reactions of hexafluoropropene oxide are initiated through attack by a nucleophile. The conversion of hexafluoropropene oxide into hexafluoroacetone in the presence of Lewis acids is the basis of further development of the chemistry of this synthetic chemical. Hexafluoropropene oxide is also regarded as a convenient source of difluorocarbene. In industrial chemistry it now plays a significant part in the manufacture of high-grade organofluorine products.

After earlier work in this laboratory on phase relations and crystal structures in the quasibinary system of hydrogen fluoride and pyridine, six lowmelting adducts with trimethyl-and triethylamine in lieu of pyridine have now been identified and their structures determined at À 150 8C:À 87 8C, monoclinic, P2 1 , Z 2), Me 3 N5 HF (m.p. À 93 8C (decomp), triclinic, P1 Å , Z 2) and Me 3 N´7 HF (m.p. À 88 8C, hexagonal, P6 3 , Z 2). Structure analysis was also performed on a further pyridine adduct: Py´6 HF (m.p.With the base protonated and the hydrogen fluoride content correspondingly deprived of one proton, all structures are ionic. They are described with respect to the F ± H´´´F and N ± H´´´F hydrogen bonding and the various H nÀ1 F À n complex ions present. These ions and others of the same kind observed in crystal structures are surveyed with regard to homology (size) and isomerism.

The article contains sections titled: 1. Introduction 2. Production Processes 2.1. Substitution of Hydrogen 2.2. Halogen ‐ Fluorine Exchange 2.3. Synthesis from Fluorinated Synthons 2.4. Addition of Hydrogen Fluoride to Unsaturated Bonds 2.5. Miscellaneous Methods 2.6. Purification and Analysis 3. Fluorinated Alkanes 3.1. Fluoroalkanes and Perfluoroalkanes 3.2. Chlorofluoroalkanes 3.3. Bromofluoroalkanes 3.4. Iodofluoroalkanes 4. Fluorinated Olefins 4.1. Tetrafluoroethylene 4.2. Hexafluoropropene 4.3. 1,1‐Difluoroethylene 4.4. Monofluoroethylene, Monofluoroethylene 4.5. 3,3,3‐Trifluoropropene 4.6. 3,3,3‐Trifluoro‐2‐(trifluoromethyl)‐prop‐1‐ene 4.7. Chlorofluoroolefins 5. Fluorinated Alcohols 6. Fluorinated Ethers 6.1. Perfluoroethers 6.1.1. Low Molecular Mass Perfluoroethers 6.1.2. Perfluorinated Epoxides 6.1.3. High Molecular Mass Perfluoroethers 6.2. Perfluorovinyl Ethers 6.3. Partially Fluorinated Ethers 7. Fluorinated Ketones and Aldehydes 7.1. Fluoro‐ and Chlorofluoroacetones 7.2. Perhaloacetaldehydes 7.3. Fluorinated 1,3‐Diketones 8. Fluorinated Carboxylic Acids and Fluorinated Alkanesulfonic Acids 8.1. Fluorinated Carboxylic Acids 8.1.1. FluorinatedAcetic Acids 8.1.2. Long‐Chain Perfluorocarboxylic Acids 8.1.3. Fluorinated Dicarboxylic Acids 8.1.4. Tetrafluoroethylene ‐ Perfluorovinyl Ether Copolymers with Carboxylic Acid Groups 8.2. Fluorinated Alkanesulfonic Acids 8.2.1. Perfluoroalkanesulfonic Acids 8.2.2. Fluorinated Alkanedisulfonic Acids 8.2.3. Tetrafluoroethylene ‐ Perfluorovinyl Ether Copolymers with Sulfonic Acid Groups 9. Fluorinated Tertiary Amines 10. Aromatic Compounds with Fluorinated Side‐Chains 10.1. Properties 10.2. Production 10.3. Uses 11. Ring‐Fluorinated Aromatic, Heterocyclic, and Polycyclic Compounds 11.1. Mono‐ and Difluoroaromatic Compounds 11.1.1. Properties 11.1.2. Production 11.1.3. Uses 11.2. Highly Fluorinated Aromatic Compounds 11.3. Perhaloaromatic Compounds 11.4. Fluorinated Heterocyclic and Polycyclic Compounds 11.4.1. Ring‐Fluorinated Pyridines 11.4.2. Trifluoromethylpyridines 11.4.3. Fluoropyrimidines 11.4.4. Fluorotriazines 11.4.5. Polycyclic Fluoroaromatic Compounds 12. Economic Aspects 13. Toxicology and Occupational Health 13.1. Fluorinated Alkanes 13.2. Fluorinated Olefins 13.3. Fluorinated Alcohols 13.4. Fluorinated Ketones 13.5. Fluorinated Carboxylic Acids 13.6. Other Classes

Professor Rolf Sammet zum 65. Geburtstag gewidmetVon den wichtigen C3-Bausteinen der organischen Fluorchemie -Hexafluorpropen, Hexafluoraceton und Hexafluorpropenoxid -ist die letztgenannte Verbindung chemisch am vielseitigsten. Hexafluorpropenoxid (HFPO) bildet ein weiteres Beispiel fur die haufig beobachtete h d e r u n g der Reaktivitat beim Ubergang von Kohlenwasserstoffen zu den perfluorierten Analoga. Die meisten Reaktionen von Hexafluorpropenoxid werden durch den Angriff eines Nucleophils eingeleitet. Die Umlagerung von Hexafluorpropenoxid zu Hexafluoraceton in Gegenwart von Lewis-Sauren ist die Basis fur eine Weiterentwicklung der Chemie dieses Bausteins. AuRerdem gilt HFPO als gunstige Difluorcarben-Quelle. In der technischen organischen Chemie spieit Hexafluorpropenoxid heute eine bedeutende Rolle fur die Herstellung hochwertiger Fluorprodukte. Einfuhrung Allgemeine Eigenschaften von HFPOHFPO ist ein farbloses, nicht brennbares, schwach riechendes Gas, das bei -27.4"C/1013 mbar siedet. Unter Druck verfliissigt ist HFPO in Abwesenheit von Wasser, Lewis-Siiuren oder Basen bei Raumtemperatur stabil. Eine spontane Polymerisation wurde nicht beobachtet. Die thermische Zersetzung tritt erst ab 150°C ein''].HFPO weist einen kiirzeren C-0-Abstand als der analoge Kohlenwasserstoff Propylenoxid auf; die C-CF,-Bindung ist langer als die C-CH3-Bindung in Propylenoxid. Die Bindungswinkel stimmen etwa iiberein14].Das "F-NMR-Spektrum ist bekannt"'. Das IR-Spektrum zeichnet sich ,durch eine starke Bande zwischen 1480 und 1620 cm-' mit einem Maximum bei 1550 cm-' aus,