Hydrogenation silver fluoride

Preparation. Silver fluoride can be prepared by dissolving Ag20 or Ag2C02 iu anhydrous hydrogen fluoride or aqueous hydrofluoric acid, evaporating to dryness, and then treating with methanol or ether. 

Silver Fluoride. Silver fluoride, AgF, is prepared by treating a basic silver salt such as silver oxide or silver carbonate, with hydrogen fluoride. Silver fluoride can exist as the anhydrous salt, a dihydrate [72214-21-2] (<42° C), and a tetrahydrate [22424-42-6] (<18° C). The anhydrous salt is colorless, but the dihydrate and tetrahydrate are yellow. Ultraviolet light or electrolysis decomposes silver fluoride to silver subfluoride [1302-01 -8] Ag2p, and fluorine. 

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. ... 

Rearrangement of fluorine with concomitant ring opening takes place in fluorinated epoxides Hexafluoroacetone can be prepared easily from perfluo-ropropylene oxide by isomerization with a fluorinated catalyst like alumina pre treated with hydrogen fluoride [26, 27, 28] In ring-opening reactions of epoxides, the distribution of products, ketone versus acyl fluoride, depends on the catalyst [29] (equation 7) When cesium, potassium, or silver fluoride are used as catalysts, dimenc products also are formed [29]... 

Alkyl fluorides can be prepared by the Finkelstein reaction. The fluoride anion is a bad leaving group the reverse reaction thus does not take place easily, and the equilibrium lies far to the right. As reagents potassium fluoride, silver fluoride or gaseous hydrogen fluoride may be used. 

DL-Valiolamine (205) was synthesized from the exo-alkene (247) derived from 51 with silver fluoride in pyridine. Compound 247 was treated with a peroxy acid, to give a single spiro epoxide (248, 89%) which was cleaved by way of anchimeric reaction in the presence of acetate ion to give, after acetylation, the tetraacetate 249. The bromo group was directly displaced with azide ion, the product was hydrogenated, and the amine acety-lated, to give the penta-A, 0-acetyl derivative (250,50%). On the other hand. 

The type of reactivity shown by the formation of Chichibabin s hydrocarbon extends to the activation of substituents other than hydrogen as well. For example, molecular silver will not usually remove fluorine from organic compounds, not even from triphenylmethyl fluoride. Yet the radical parafluorophenyldiphenylmethyl reacts with molecular silver to give silver fluoride.88... 

The cis-glycosyl fluorides of the peracetylated 2-deoxy-2-fluoro saccharides have been obtained by addition of trifluoro(fluoroxy)meth-ane to the corresponding peracetylated glycals, whereas the preparation of the other derivatives was achieved by treatment of a suitable precursor with hydrogen fluoride or silver fluoride in acetonitrile peracetylated 2-deoxy-2-fluoro-a-Drmannopyranosyl fluoride70,71 was prepared by equilibration of the /3 anomer in hydrogen fluoride. 

In reactions in which HC1, HBr, or HI are evolved there is a convenient way of detecting and following the course of the reaction. Gas will be evolved and a bead of silver nitrate solution in a small loop of nichrome wire placed in this gas stream will become opaque, if these gases are present. Hydrogen fluoride will not do this since silver fluoride is very soluble in water. If a simple test for hydrogen fluoride is desired, a similar bead of calcium chloride will serve very well. 

E. Fremy also obtained anhydrous hydrofluoric acid by decomposing lead or silver fluoride in a platinum tube by means of purified and dry hydrogen. 

Organic compounds Organic fluorine compounds arc made by reaction of the corresponding alkane chloro-compounds with silver fluoride, mercurous fluoride, antimony trifluoride, titanium tetrafluoridc. and the arene fluoro-compounds by the diazo-reaction using hydrogen fluoride, and otherwise. The effect of the continued replacemenl of hydrogen atoms by fluorine atoms is an initial increase in reactivity, followed by a reversal of this effect, so lhal the highly substituted compounds arc relatively inert, See also Fluorocarbon. 

Halogen exchange reactions, too, are valuable sources of fluorinated pyrimidines, especially 2-, 4-, and 6-fluoro derivatives. Sources of fluoride ion have included hydrogen, sodium, potassium, cesium, antimony, silver fluorides, and sulfur tetrafluoride. All of the reactions required heating. Prepared from nucleophilic fluorination processes have been... 

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