thio)propanoate, 777-80-0; cis-dihydro-5-methyl-4-(phenylthio)-2-(3H)-furanone, 75717-32-7; trons-dihydro-5-methyl-4-(phenylthio)-2(3H)-furanone, 75717-33-8; 3-(phenylthio)cyclopentanone, 75717-34-9; 3-(phenylthio)cyclohexanone, 35155-84-1; (£)-3-(phenylthio)-2propenenitrile, 2974-75-6; (Z)-3-(phenylthio)-2-propenenitrile, 2974-76-7; ethyl (£)-3-(phenylthio)-2-propenoate, 75717-35-0; ethyl (Z)-3-(phenylthio)-2-propenoate, 75717-36-1; methyl (£)-2-methyl-3-(phenylthio)-2-propenoate, 71847-74-0; methyl (Z)-2-methyl-3-(phenylthio)-2-propenoate, 66349-63-1; 5-methyl-4-(phenylthio)-2-(5£)-furanone, 75717-37-2; 3-(phenylthio)-2-cyclopenten-l-one, 75717-38-3; 3-(phenylthio)-2-cyclohexen-l-one, 75717-39-4; thiophenol, 108-98-5; ethyl bromide, 74-96-4; (phenylthio)ethane, 622-38-8; (phenylthio)ethene, 1822-73-7; l-(phenylthio)octane, 13910-16-2; (£)-l-(phenylthio)-l-octene, 75717-40-7; (Z)-l-(phenylthio)-!octene, 75717-41-8; (phenylthio)cyclohexane, 7570-92-5; (phenylthio)cyclohexene, 4922-47-8.

Perfluoroalkanesulfonic acids and their derivatives are of commercial significance because of their unusual acid strength, chemical stability, and the surface activity of the higher members of the series (eight carbons and larger). The best method of preparation is via the perfluorinated sulfonyl fluorides derived from electrochemical fluorination, although other methods including direct fluorination with fluorine gas are known. The first member of the series, trifluoromethanesulfonic acid, is one of the strongest acids known. Alkyl esters of trifluoromethanesulfonic acid are among the best leaving groups known and are commonly used in that capacity in displacement reactions. Lithium trifluoromethanesulfonate solutions are very conductive and can find application as electrolytes in primary lithium batteries and as antistats for films. Derivatives of the longer‐chain perfluoroalkanesulfonic acids have a number of unique surface‐active properties and have formed a basis for a number of commercial products. The longer‐chain acids and their salts, particularly C 8 F 17 SO 3 H and higher, are surface‐active agents in aqueous media. They reduce the surface tension of water to levels not possible with hydrocarbon surfactants. Preparation of difunctional perfluoroalkanesulfonates and their derivatives is discussed, including fluorosulfonylacetyl fluoride. Fluorosulfonyldifluoracetyl fluoride is an important industrial intermediate used in the production of Du Pont's Nafion ion‐exchange membranes and in many other applications.

No abstract

Perfluorinated carboxylic acids are corrosive liquids or solids. The acids are completely ionized in water. The acids are of commercial significance because of their unusual acid strength, chemical stability, high surface activity, and salt solubility characteristics. The higher members of the series have the property of decreasing the surface tension of aqueous solutions well below the point possible with any type of hydrocarbon surfactant. There are five methods for the preparation of long‐chain perfluorinated carboxylic acids and derivatives: electrochemical fluorination, direct fluorination, telomerization of tetrafluoroethylene, oligomerization of hexafluoropropylene oxide, and photooxidation of tetrafluoroethylene and hexafluoropropylene. In general, the reactions of the perfluoroacids are similar to those of the hydrocarbon acids, although in some cases the electronegativity of the perfluoroalkyl groups make formation of certain derivatives easier or harder. A general summary of formation and properties of the derivatives of perfluorinated acids is discussed. Data on the fluorinated dicarboxylic acids and their derivatives are also summarized.

Tiglinsäure (I) liefert das Dianion (II), das mit Allylbromid in hoher Gesamtausbeute zu (IV) und geringen Mengen des Isomeren (V) reagiert.