Aluminum chlorofluoride

Later, DuPont researchers used their aluminum chlorofluoride (ACF) catalyst13 (rule. supra) to rearrange allyl iodide 7 to vinyl iodide 8 as a 1 1 EjZ mixture.14... 

Researchers at Daikin Kogyo have reported that perfluorobut-2-ene (2a) can be obtained in 98% yield by passing but-l-ene la over alumina at 250 C.21,22 The isomerization of per-fluoro(3-phenylprop-l-ene) (Id) to 2d has also been achieved quantitatively with the DuPont catalyst aluminum chlorofluoride (ACF).14... 

Perfluorobuta-1,3-diene (14) is converted by the DuPont catalyst aluminum chlorofluoride (ACF see Section 5.1.1.) into but-2-yne 15 in nearly quantitative yield, the only reported case of a Lewis acid catalyzed diene-acetylene rearrangement.14... 

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-... 

This condensation is also catalyzed by aluminum chlorofluoride. Other examples of this type of reaction are summarized in Table 30. 

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). 

Significantly stronger Lewis acid aluminum chlorofluoride (ACF, AlCLF ) was shown to be advantageous in promoting electrophilic [2 + 2] cycloadditions of hexafluoroacetone. ACF, known to be an effective catalyst for the condensation of halomethanes and fluoroolefins " with fluoroethylenes, was also found to catalyze the reaction of HFA with fluoroethylenes. For example, the reaction of HFA and TFE gives the corresponding F-(2,2-dimethyloxetane) 11 in moderate yield along with some polytetrafluoroethylene (Scheme 2.1) ... 

The reaction of perfluorinated cyclic amines with strong Lewis acids, such as SbFs or aluminum chlorofluoride (ACF), at elevated temperature results in rapid cleavage of amine, leading to the formation of cyclic perfluorinated imidoyl fluorides (Fig. 9.23). In contrast to AICI3 reactions, this process is catalytic. The outcome of the reaction depends on the structure of amine. For example, the reaction of A-alkyl piperidines or morpholines leads to the elimination of perfluoroalkane... 

Petrov, V.A. Krespan, C.G. Smart, B.E. Electrophihc reactions of fluorocarbons under the action of aluminum chlorofluoride, a potent Lewis acid. J. Fluorine Chem. 1996, 77(2), 139-142. 

T. Krahl, R. Stosser, E. Kemnitz, G. Scholz, M. Feist, G. Silly, J.-Y. Buzare, Structural insights into aluminum chlorofluoride (ACF), Inorg. Chem., 42,6474-6483 (2003). 

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. 

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. 

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