Mercuric fluoride, preparation

Alkyl fluorides have been prepared by reaction between elementary fluorine and the paraffins, by the addition of hydrogen fluoride to olefins, by the reaction of alkyl halides with mercurous fluoride, with mercuric fluoride, with silver fluoride, or with potassium fluoride under pressure. The procedure used is based on that of Hoffmann involving interaction at atmospheric pressure of anhydrous potassium fluoride with an alkyl halide in the presence of ethylene glycol as a solvent for the inorganic fluoride a small amount of olefin accompanies the alkyl fluoride produced and is readily removed by treatment with bromine-potassium bromide solution. Methods for the preparation of alkyl monofluorides have been reviewed. ... 

Waterfeld, A. et al., J. Chem. Soc., Chem. Comm., 1982, 839 Reaction of chlorine fluoride with trifluorosulfur nitride is rather hazardous and may lead to violent explosions. A safer alternative preparation is to use chlorine and mercuric fluoride in place of chlorine fluoride. 

In this work on compounds containing the C—F link, it was obviously desirable to prepare 2-fluoroethanol, both for toxicity tests on the compound itself, and as a starting material for the production of other fluorine compounds. Swarts1 was unable to obtain 2-fluoroethanol by the action of silver fluoride or mercuric fluoride on either ethylene chlorohydrin or ethylene bromohydrin. He obtained acetaldehyde in each case. He ultimately obtained fluoroethanol in very poor yield by the indirect method of hydrolysing fluoroacetin (from bromoacetin and mercuric fluoride) for 80 hr. with dilute mineral acid. 

Silver fluoride is difficult to prepare in anhydrous form, and it has the further disadvantage that only half of its fluorine is available because the exchange reaction stops with the formation of the compound AgF AgCl. Mercuric fluoride and mercurous fluoride are, therefore, more convenient reagents despite the lower fluorine content of mercurous fluoride. 

Preparation of Mercurous Fluoride.38 A solution of 40 g. of red mercuric oxide in a mixture of 28 cc. of concentrated nitric acid and 60 cc. of... 

Methyl fluoroacetate was first prepared by Swarts in small yield by the action of silver or mercurous fluoride on methyl iodoacetate. The method is impracticable for large-scale work and therefore the preparation was reinvestigated in detail. Methyl chloroacetate was used in place of the expensive iodoacetate, and a variety of fluorinating agents was tried. It was found that fluorination could be effected by heating methyl chloroacetate in a rotating autoclave with potassium fluoride at 220° for 4 hr. Sodium fluoride, on the other hand, was almost without action. 

How might you prepare mercuric fluoride using xenon tetrafluoride Write an equation as part of your answer. 

In the Koenigs-Knorr method and in the Helferich or Zemplen modifications thereof, a glycosyl halide (bromide or chloride iodides can be produced in situ by the addition of tetraalkylammonium iodide) is allowed to react with a hydrox-ylic compound in the presence of a heavy-metal promoter such as silver oxide, carbonate, perchlorate, or mercuric bromide and/or oxide,19-21 or by silver triflu-oromethanesulfonate22 (AgOTf). Related to this is the use of glycosyl fluoride donors,23 which normally are prepared from thioglycosides.24... 

The iodine atom in the monoiodide may be replaced by other groups and, by reaction with silver salts, for example, As(CF3)2CN (b.p. 89 5°) and As(CFg)2SCN (b.p. 116—118°) are readily prepared. Reaction of the monoiodide with mercury gives the cacodyl As2(CF3)4 (b.p. 106 to 107°), while with mercuric oxide the oxide As2(CF3)40 (b.p. 95—97°) is formed. The chemistry of these substances has not yet been studied in detail, but it is noteworthy that hydrolysis of the perfluorocacodyl gives both fluoroform and fluoride, which parallels the observations made on the diphosphine. 

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