Antimony chlorofluorides

At 225—275°C, bromination of the vapor yields bromochloromethanes CCl Br, CCl2Br2, and CClBr. Chloroform reacts with aluminum bromide to form bromoform, CHBr. Chloroform cannot be direcdy fluorinated with elementary flourine fluoroform, CHF, is produced from chloroform by reaction with hydrogen fluoride in the presence of a metallic fluoride catalyst (8). It is also a coproduct of monochlorodifluoromethane from the HF—CHCl reaction over antimony chlorofluoride. Iodine gives a characteristic purple solution in chloroform but does not react even at the boiling point. Iodoform, CHI, may be produced from chloroform by reaction with ethyl iodide in the presence of aluminum chloride however, this is not the route normally used for its preparation. 

A wide range of Lewis acids have been used in the extensive studies of the conversion of perfluoro(2-melhyloxirane)28 into hexafluoroacetone. including antimony(V) fluoride,31-32 aluminum trichloride,30 aluminum chlorofluoride (from A1C1, and CFClj).23-33 alumina pre-... 

The desired extent of fluorination of the starting material may dictate the fluorinating agent to be used. For example, fluorine converts silicon tetrachloride to silicon tetra-fluoride, whereas antimony(III) fluoride promotes the reactions which produce the chlorofluorides, SiCl3F, SiCl2F2, and SiCIFs. 

There appears to be only one really satisfactory method for preparing pure germanium(IV) fluoride. This method involves the thermal decomposition of barium hexafluoro-germanate1 in a quartz or Vycor tube, a method analogous to that described for the preparation of silicon tetrafluoride (synthesis 47). Germanium(IV) fluoride has also been produced by the fluorination of germanium(IV) chloride with antimony (III) fluoride 2 however, it is necessary to distill fractionally the mixture of chlorofluorides resulting from the reaction. 

When Booth and Mericola (1940) allowed thionyl chloride to react with antimony trifluoride containing some antimony pentachloride they obtained as products both thionyl fluoride and thionyl chlorofluoride, SOC1F (21). The compound was also produced in the laboratory of Otto Ruff (1937) but the work was not published until 1951. For this work iodine pentafluoride was heated with thionyl chloride (165). 

Moissan and Lebeau (1901) produced sulfuryl fluoride by the combination of sulfur dioxide with fluorine (217). Other processes which have been used to produce the gas are (a) the thermal decomposition of barium fluorosulfonate or certain other fluorosulfonates (188, 221, 808), (b) the reaction of sulfur dioxide with chlorine and hydrogen fluoride in the presence of activated charcoal at 400° (11), (c) the reaction of sulfur dioxide and chlorine with potassium or sodium fluoride at 400° (328), (d) the disproportionation of sulfuryl chlorofluoride at 300-400° (328), (e) the reaction of sulfuryl chloride with a mixture of antimony trifluoride and antimony pentachloride at about 250° (86), (f) the reaction of sulfur dioxide with silver difluoride (86), (g) the reaction of thionyl fluoride with oxygen in an electrical discharge (314), (h) electrolysis of a solution of fluorosulfonic acid in hydrogen fluoride (264), ( ) the reaction of fluorine with sodium sulfate, sodium sulfite or sodium thiosulfate (229, 239), (j) the reaction of hydrogen fluoride with sulfuryl chloride (820). 

CHLORINATION Antimony(V) chloride, lodobenzene dichloride. Molybdenum(V) chloride. Sodium hypochlorite. Sulfuryl chlorofluoride. Trichloroisocyanuric acid. 

In similar fashion and in contrast to its isomerization by fluoride ion and other bases to perfluoropropionyl fluoride (6), HFPO is transformed by Lewis acids such as antimony pentafluoride ° or aluminum chlorofluoride into another isomer, hexafluoroacetone (20). 

The 1,2-dimethylbenzocyclobutadiene dication (316), a 6-7c-electron molecule, has been prepared by reaction of 1,2-dimethylbenzocyclobutene-l,2-diol with antimony pentafluoride in sulphuryl chlorofluoride at low temperature. The H n.m.r. spectrum of (316) showed equivalent methyl group signals at 84.42 and an aromatic proton signal at 8 9.10. The n.m.r. spectrum showed five signals at chemical shifts indicated below. The spectra are comparable with those of other cyclobutadiene dications, supporting the fully delocalized structure of (316). The ion was stable below 30 °C. Attempts to prepare the parent dication were not successful. 

The halocarbon gases such as pentafluoroethane (HFC-125), 1,1,1,3,3,3-hexafluoropropane (HFC-236fa) and 2H-heptafluoropropane (HFC-227ea) are manufactured by either vapor phase or liquid phase catalytic fluorination pathways in continuous mode of operation. The successful catalysts for vapor phase fluorination processes are usually chromium (111) oxide (preactivated with HF) and/or aluminum compoimds doped with Lewis acids such as Co, Ni or Zn. Similarly, antimony (V) chlorofluoride (SbCl Fp/HF is preferred as catalyst in liquid phase fluorination of chlorinated starting compounds. Some of the methods practiced for obtaining individual halocarbons are listed here. 

Pentafluoroethane is also prepared by contacting a steady stream of HFC-143 a [73] chlorine and anhydrous HF with antimony (V) chlorofluoride in liquid phase at 100-130°C. 

Olah, G. A., and J. Lukas Stable Carbonium Ions. XLVII. Alkylcarbonium Ion Formation from Alkanes via Hydride (Alkide) Ion Abstraction in Fluorosulfonic Acid-Antimony Pentafluoride-Sulfuryl Chlorofluoride Solution. J. Amer. Chem. Soc. 89, 4739 (1967). 

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