Antimony trifluoride preparation

Alkoxy fluorides are prepared using acetyl fluoride. Alternatively, antimony trifluoride can be used to replace one alkoxyl by fluorine (58) ... 

An attempt to prepare 1 -bromo-2-fluoroethane by the partial fluorination of ethylene dibromide by means of antimony trifluoride was not very successful. The compound was best prepared by the action of phosphorus tribromide on F.E.A. The compound was relatively non-toxic and the bromine atom rather unreactive, but considerably more reactive than the chlorine atom in chlorofluoroethane. For example, bromofluoroethane was readily converted by means of potassium thiocyanate into 2-fluoroethyl thiocyanate. As a lethal inhalant the toxicity of the thiocyanate was inferior to that of M.F.A. Toxicity by injection, however, appeared to be higher. 

It may also be prepared from antimony trifluoride and fluorine, or by treating antimony pentaoxide with aqueous hydrofluoric acid and evaporing water. 

Antimony trifluoride, 16 181 preparation of, 7 14-15 solubility of, 7 6-7 Antimony trifluoroacetates, 17 12, 13 Antiperspirants, 36 16 Anti-Stokes emission, 35 342-343 Antitumor agents DNA and RNA cleavers, 45 252 phosphazotrihalides as, 14 90, 91... 

Fluorophosphites are prepared by a two step sequence. The initial step is the reaction of phenolic materials with phosphorus trichloride to prepare a chlorophosphite intermediate. The chlorophosphite is then treated with a fluoride source to convert the chloro- intermediate into the desired fluorophosphite product. Many different fluoride sources have been described in the literature including anhydrous hydrogen fluoride, anhydrous potassium fluoride, and antimony trifluoride. While any of these fluoride sources can be used successfully, we have found that antimony trifluoride (10) works well for small scale, lab preparations. 

It must be concluded, therefore, that fluorophosphines are strongly reducing, a fact which was confirmed in further attempts at their preparation, using different reagents in the fluorination of chlorophosphines. There was either no reaction at all under the experimental conditions—e.g., with alkali fluorides in benzene as a solvent—or the trivalent phosphorus in the starting chlorophosphine was readily converted to the quinquevalent state—e.g., when phenyldichlorophosphine reacted with sodium fluoride in the presence of an antimony trioxide catalyst in a polar solvent such as acetonitrile to give phenylphosphonic difluoride. Recent Russian work showed that phenyldichlorophosphine was converted into phenyltetrafluoro-phosphorane, C6H5PF4, when it reacted with antimony trifluoride (34),... 

The behavior of a number of chlorine derivatives of methane, ethane, and propane toward antimony trifluoride activated by the trifluorodichloride is shown in Table I. The yield given for each product is the maximum obtained when the reaction was adjusted for the preparation... 

For the preparation of this product, the antimony trifluoride must be converted completely to SbFjCla-... 

Preparation of Antimony Trifluorodichloride (SbF3Cl2). This is made in the steel reaction vessel, described on p. 59. A known quantity of antimony fluoride is placed in the vessel the vessel is evacuated, the needle valve is closed, and the whole is weighed. Connection is established to a chlorine cylinder, and the needle valve is opened to permit qhlorine to fill the vessel. Part of it is absorbed rapidly by the salt, with evolution of heat. Soon the reaction slows down as indicated by the rate of pressure fall when the needle valve is dosed. Weighing indicates the amount of chlorine present in the vessel. When the absorption practically ceases, the valve is closed, and the connection with the chlorine tank is removed. The reaction vessel is alternately heated gently, then allowed to cool in order to permit SbFsCl2, which is a viscous liquid, to flow and expose fresh surfaces of crystalline antimony trifluoride. The operation is ended after the absorption of the desired quantity of chlorine. 

Antimony trifluoride is easily prepared by dissolving Sb203 in aqueous HF or in an excess anhydrous hydrogen fluoride. The aqueous HF solutions are carefully evaporated to dryness. 

Antimony trifluoride [7783-56-4] M 178,8, m 292", b 376", dj 4.379. It crystallises from MeOH to remove oxide and oxyfluoride, then it is sublimed under vacuum in an aluminium cup on to a water-cooled copper condenser. Its solubility is 443g/100g in H2O at 20 and 562g/100g in H2O at 30 with partial hydrolysis. [Woolf J Chem Soc 279 7955, Kwasnik in Handbook of Preparative Inorganic Chem (Ed. Brauer) Academic Press Vol I p 199 7965]. 

Since the simplest F-l,3-dithietane (38) cannot be prepared by dimerization of thiocarbonyl fluoride, probably due to propensity of the latter to polymerize, a different synthetic approach is employed for its synthesis. Two-step process includes photocyclodimerization of Cl2C=S and Swarts-type fluorination of the dimer by antimony trifluoride to give 38 (Scheme 2.20). Compound 38 can be a source of very pure thiocarbonyl fluoride, when pyrolyzed at 500°C." ... 

Fluorothiophenes 2-Fluorothiophene was prepared first time in low yield by the fluorination of 2-iodothiophene by antimony trifluoride. 

Arsenic, and Antimony.— Tbe dichloro(polyfluorophenyl)phosphines (247), prepared as shown (Scheme 56), react with antimony trifluoride to give mainly the corresponding difluorophosphines (248), but low yields (15— 20%) of the tetrafluorophosphoranes (249) are also produced in some cases (X = H or OMe). Treatment of the difluorophosphines (248) with antimony trifluoride in the presence of chlorine gives the phosphoranes (249 X = H, F, OMe, or CF3) in good yields, and some reactions of these compounds are illustrated in Scheme 56. The... 

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