Bis fluoroxy difluoromethane

Bis(fluoroxy)difluoromethane is prepared in essentially stoichiometric amounts by the fluorination of carbon dioxide with an 

Although the procedure described utilizes metal vessels for ease of treating the cesium fluoride and to avoid the formation of large amounts of silicon tetrafluoride, glass may be used. This procedure has been used for preparation of up to 0.015 mole of CF2(0F)2 at a time with the aid of liquid nitrogen to condense excess fluorine into the vessel. The method is analogous to that used in the preparation of pentafluorosulfur hypofluorite by the static, catalytic fluorination of thionyl fluoride in the presence of cesium fluoride.  

A charge of 3.04 g. (0.020 mole) of cesium fluoride (99%) and several 7-mm. steel balls are placed in a 75-ml. stainless-steel cylinder. A polyfluorocarbon-packed stainless-steel needle valve equipped with a brass 10/30 standard-taper inner joint is attached. The steel balls help to powder the cesium fluoride. The cesium fluoride is then dried by subjecting it to continued pumping at 190° in a vacuum oven for about 4 hours. 

Commercial fluorine is passed through a sodium fluoride scrubber and a —184° cold trap before use to remove hydrogen fluoride and condensable materials, respectively. The reaction vessel is treated with an excess of fluorine at 190° for 4 hours before use. The excess fluorine is then destroyed by pumping through a soda-lime trap. 

The vessel and a suitable storage tube are attached to a standard vacuum line and evacuated. The vessel is allowed to warm, and the product is condensed into the storage tube at — 184°. Nearly quantitative (av. 99.7%) conversion of carbon dioxide to bis(fluoroxy)difluoromethane is realized under these conditions. Anal. Calcd. for CF40 F, 63.3. Found F, 62.3. 

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Bis(fluoroxy)difluoromethane reacts with carbonyl difluoride over CsF to yield a bis(trifluoromethyl) trioxide, CF3OOOCF3, bp -19°C, or the peroxy acyl fluoride, CF300C(0)F, depending on conditions (equation 55). At low temperature, the trioxide is favored. 

Incomplete conversion of carbon dioxide may occur if the reaction vessel is not properly fluorinated, if a deficiency of fluorine is used, or if the reaction time is too short. Bis-(fluoroxy)difluoromethane can be separated from most impurities... 

A. E. Croce and E. Castellano [Int. J. Chem. Kinet., 14, 647 (1982)] studied the kinetics of the gas-phase thermal reaction between bis(fluoroxy)difluoromethane CF2(OF)2 and carbon monoxide over the temperature range 110 to 140°C ... 

Also, low molecular weight fluorine-containing polymers form from peifluoroaromatic compounds through a loss of aromaticity when they react with bis(fluoroxy)difluoromethane. More interesting is the formation of poly(a,a,a, a -tetrafluoro-/7-xylylene) by a polymerization technique that closely resembles the preparation of poly(p-xylylene) by vacuum pyrolysis of a dimer ... 

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