Tetrafluoride synthesis

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. 

Xenon tetrafluoride, synthesis 66 Xenon hexafluoride, synthesis 67 Xenon difluoride, synthesis 68... 

Xenon hexafluoride may be prepared in essentially the same way as xenon tetrafluoride (synthesis 66), except for increasing the fluorine-to-xenon ratio and the final pressure at reaction temperature.Variations of temperature, pressure, mol ratio, and time make possible the formation of xenon difluoride, xenon tetrafluoride, or xenon hexafluoride. The conditions described below have been found to give good yields and purity for xenon hexafluoride. 

The apparatus and experimental procedures are similar to those used for the tetrafluoride (synthesis 66), except for the use of the heavier-walled vessel H instead of the vessel F. In order to add the required amount of fluorine, it will be necessary either to use a larger vessel G or to repeat the measuring and condensing procedures. The xenon-to-fluorine mol ratios used are about 1 20 [0.689 g. (0.00525 mol) of xenon and 4.18 g. (0.110 mol) of fluorine]. The gas mixture is heated to 300° for 16 hours. The hexafluoride is purified by distillation, the less volatile fraction of lower fluorides being discarded. The purity may be checked by examination of the infrared spectrum, noting the presence of bands at 520 and 612 cm. and the absence of peaks for the difluoride and the tetrafluoride. The spectrum should also be studied in the 900- to 1000-cm. region, where oxyfluorides have fundamentals, for e.xample, XeOF4 at 928 cm. h... 

The standard synthesis method features side-chain chlorination of a methylpyridine (picoline), followed by exchange-fluoriaation with hydrogen fluoride or antimony fluorides (432,433). The fluoriaation of pyridinecarboxyHc acids by sulfur tetrafluoride (434) or molybdenum hexafluoride (435) is of limited value for high volume production operations due to high cost of fluorinating agent. 

M. H. West, M. M. Maitinez, J. B. Nielson, D. C. Court, and Q. D. Appeit, Synthesis of Uranium Metal UsingEaser-InitiatedTeduction of Uranium Tetrafluoride by Calcium Metal, LA-12996-MS, Los Alamos National Laboiatoiy, N.M., 1995. 

The recent discovery of a convenient synthesis of sulfur tetrafluoride from sulfur dichloride and sodium fluoride in acetonitrile invited the application of this reagent in fluorination reactions. Hasek, Smith and Engelhardt showed that carboxylic acids and their derivatives can be converted into trifluoromethyl derivatives and that aldehydes and ketones are converted into 5 em-difluoro compounds. They also observed that the reaction was acid... 

A nonconventional synthesis of the known inhalation anaesthetic, 2-bromo-2 chloro-l,l,l-trifluoroethane (Halothane), based on the reaction of ethyl 1,2 di bromo-1,2-dicliloroethyl ether with anhydrous hydrogen fluoride and sulfur tetrafluoride, has been patented The reaction presumably involves cleavage of the ether linkage, followed by fluorination of the intermediate bromochloroacetyl halide with sulfur tetrafluoride, ethyl halides are the by-products [2] (equation 2)... 

Fluorination of tetrachlorophthalic acid hemihydrate with an excess of sulfur tetrafluoride, or of tetrachlorophthalic anhydride with a sulfur tetrafluonde-hydro-gen fluoride reagent, provides an efficient synthesis of 4,5,6,7- tetrachloro-1,1,3,3-tetrafluorol,3-dihydroisobenzofuran. 3,4,5,6-Tetrachloro-2-(trifluoromethyl)-benzoyl fluoride is formed as a by-product [217] (equation 111). 

Thionyl fluoride, as by-product in sulfur tetrafluoride reactions, 41, 105 toxidty of, 41,105 Thiophene-2-OL, 43, 55 2(5H)-Thiophenone, 43, 55 Thiosemicarbazide, in synthesis of 1,2,4 triazole, 40, 99 reaction with formic acid to yield l-formyl-3-thiosemicarbazide, 40,99... 

The starting point for the synthesis of xenon compounds is the preparation of xenon difluoride, XeF2, and xenon tetrafluoride, XeF4, by heating a mixture of the elements to 400°C at 6 atm. At higher pressures, fluorination proceeds as far as xenon hexafluoride, XeFfi. All three fluorides are crystalline solids (Fig. 15.27). In the gas phase, all are molecular compounds. Solid xenon hexafluoride, however, is ionic, with a complex structure consisting of XeF< + cations bridged by F anions. 

In the usual high-vacuum apparatus I placed aluminum borohydride onto a sample of uranium tetrafluoride. I observed an immediate reaction, with formation of green crystals which could be moved about the vacuum apparatus. As it happened, on the very day I was performing the synthesis, we had a visit from Professor H. C. Urey, who was in charge of the overall study. He immediately asked us to increase our research effort and undertake to prepare uranium tetraborohydride on a relatively large scale, adequate for testing. 

The synthesis of bis(rj8-cyclooctatetraene)uranium(IV) (uranocene)J from uranium tetrachloride and (cyclooctatetraene)dipotassium was first published in 1968.1 The method reported here is a modification of that procedure and is suitable for a large variety of cyclooctatefraene complexes.2-4 BisO 8-cyclo-octatetraene)uranium(IV) has also been prepared by the reaction of uranium tetrafluoride with (cyclooctatetraene)magnesium in the absence of solvent.5 Direct reaction of finely divided uranium metal with cyclooctatetraene vapors at 150° also gives some uranocene.5 However, both methods give low yields. 

Sulfur tetrafluoride is obtainable in one-pound cylinders from the Organic Chemicals Department of E. I. du Pont de Nemours and Co., Wilmington, Delaware. Directions for its synthesis by the action of sodium fluoride on sulfur dichloride in acetonitrile have been published,2 and a more detailed version of these directions has been submitted to Inorganic Syntheses. 

Sodium toluene dispersion of, 55, 65 Sodium p-toluenesulfinate, 57, 103 Spiro[4 n] alkenones, 58, 62 Spiro[cyclopentane-l,l -indene] 55, 94 Squalene, 56, 116 Squalene, 2,3-epoxy, 56, 116 Stannic chloride, 56, 97 Steroids synthesis, 58, 85 E Stilbene, 55, 115,58, 73 z-Stilbene, 58, 133 Styrene, 56, 35,58, 43 Styrene glycol, 55, 116 Styrene glycol dimesylate, 55, 116 Succinic acid, 58, 85 Succinic anhydride, 58, 85 Sucunimide, 56, 50, 58, 126 Succimmide, Vbromo, 55, 28, 56, 49 SULFIDE CONTRACTION, 55, 127 Sulfide, dimethyl-, 56, 37 SULFIDE SYNTHESIS, 58, 143,58, 138 SULFIDE SYNTHESIS ALKYL ARYL SULFIDES, 58, 143 SULFIDE SYNTHFSIS DIALKYL SULFIDES, 58, 143 SULFIDE SYNTHESIS UNSYMMETRI-CAL DIALKYL DISULFIDES, 58, 147 SULFONYL CYANIDES, 57, 88 Sulfur tetrafluoride, 57, 51... 

Moissan attempted to harness elemental fluorine for organic synthesis, but found that he could not control the reactions, as combustion or detonation usually occurred.1 From carbon itself (and also in other ways), he claimed to have made carbon tetrafluoride, but this was not correct as the quoted boiling point was far too high. In fact, the isolation of fluorine had virtually no impact on the synthesis of organic fluorides for over 40 years. 

The convenient laboratory synthesis of sulfur tetrafluoride consists of halogen exchange between sulfur dichloride and sodium fluoride.10 Two general versions of this synthesis are possible. 

Synthesis of sulfur tetrafluoride by fluorination of sulfur monochloride with elemental fluorine in the presence of antimony(III) chloride or phosphorus trichloride as a catalyst has also been reported 22-23 sulfur dichloride, which is formed as the byproduct, is converted back to sulfur monochloride in an absorber filled with granulated sulfur and then recycled. 

Fluorination of tetrachlorophthalic acid with sulfur tetrafluoride alone or of tetrachlorophthalic anhydride with a sulfur tetrafluoride/hydrogen fluoride mixture provides an efficient synthesis... 

Both aromatic and aliphatic fluoroformates 7 can be readily prepared from phenols or alcohols and carbonyl difluoride and treated with sulfur tetrafluoride without isolation. Hydrogen fluoride evolved in the reaction of hydroxy compounds with carbonyl di fluoride serves as a catalyst for the consecutive reaction with sulfur tetrafluoride.15<)-162 This provides a general, convenient, direct synthesis of aryl and alkyl trifluoromethyl ethers 5 from phenols and alcohols. When the intermediate fluoroformate 7 is isolated prior to treatment with sulfur tetrafluoride, at least one mole equivalent of hydrogen fluoride is necessary to promote the fluorination reaction. 159 163 Representative examples of the conversion of hydroxy compounds 6 into trifluoromethyl ethers 5 via intermediate fluoroformates 7 are given (for other examples 7 -> 5, see Houben-Weyl, Vol. E4, pp 628. 629). 

Nitriles are resistant to reaction with sulfur tetrafluoride under the conditions generally used for fluorination of oxygen functions. Acetonitrile, which is used as the solvent in the laboratory synthesis of sulfur tetrafluoride (see Section 8.1.2.), is particularly resistant and no reaction occurs up to 260"C, at which temperature extensive decomposition takes place and 1,1,2-tri-fluoroethyliminosulfur difluoride is formed in low yield,202... 

Silicon tetrafluoride, for laboratory use, can be obtained from fluorosilicic acid1 or by thermolysis at 450-600°C of barium or disodium hexafluorosilicate.2 3 However, the most conventional synthesis of pure silicon tetrafluoride is by fluorination of silicon tetrachloride with sodium fluoride in acetonitrile.4... 

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