Oxidation with oxygen fluorides

Fluorobromoacetaldehydes Difluorobromoacetal-dehyde (DFBA) and fluorodibromoacetaldehyde (FDBA) were prepared by two different routes (18). In the first approach 1.1 -difluoro-2,2-dibromoethylene was oxidized with oxygen at O C and gave in good yield a mixture of difluorobromoacetyl bromide and fluoro-dibromoacety1 fluoride. This reaction undoubtedly goes via the 1, 1-difluoro-2,2-dibromoethylene oxide, which could not be isolated. 

Perfluoroepoxides have also been prepared by anodic oxidation of fluoroalkenes (39), the low temperature oxidation of fluoroalkenes with potassium permanganate (40), by addition of difluorocarbene to perfluoroacetyl fluoride (41) or hexafluoroacetone (42), epoxidation of fluoroalkenes with oxygen difluoride (43) or peracids (44), the photolysis of substituted l,3-dioxolan-4-ones (45), and the thermal rearrangement of perfluorodioxoles (46). 

Coordination Complexes. The abiUty of the various oxidation states of Pu to form complex ions with simple hard ligands, such as oxygen, is, in order of decreasing stabiUty, Pu + > PuO " > Pu + > PuO Thus, Pu(Ill) forms relatively weak complexes with fluoride, chloride, nitrate, and sulfate (105), and stronger complexes with oxygen ligands (Lewis-base donors) such as carbonate, oxalate, and polycarboxylates, eg, citrate, and ethylenediaminetetraacetic acid (106). The complexation behavior of Pu(Ill) is quite similar to that of the light lanthanide(Ill) ions, particularly to Nd(Ill)... 

Xenon is currently exciting to scientists because, contrary to earlier belief, it has now been learned that it is not completely inert. Under the right conditions, xenon can be made to react with fluorine. It makes several different fluoride compounds, and these in turn react with oxygen to make xenon oxides. Such compounds are not used for much as yet, but the very fact of their being possible has reminded chemists that no scientific ques-... 

A liquid perfluorocarbon was being used as solvent in an oxidation by oxygen under pressure more energy was released than expected [1], It is cautioned that fluorocarbons are not inert to oxidation, presumably to carbonyl fluoride. An explosion has been experienced with perfluorotoluene in like circumstances [2], A correspondent reports that perfluorotoluene is flammable in air, more saturated perfluorocarbons in pure oxygen [3], Another detailed the combustion performance of polytetrafluoroethylene 148 kcal/mole ignition temperature not below 465°C at 7000 psi of oxygen [4], the product is mostly carbonyl fluoride. Other oxidants may also present a risk in extreme circumstances. 

Partial substitution of fluorine for oxygen in VO2 and V 2O5 has been achieved by treating these oxides with aqueous hydrofluoric acid under pressure. The new phases of composition V02. xFjc (for 0 < x < 0.2) and V205 Fj( (for 0 < X < 0.025) were obtained and characterized by X-ray diffraction studies. The oxide-fluoride bronze K0.25VO0.75F2.25 has been prepared from the high-temperature reaction of KVO3 and VF3 and the unit cell parameters have been determined. 

Blends of perchloryl fluoride with halogen fluorides are homogeneous and stable. When these are used as storable liquid oxidizers for rocket propulsion, the halogen fluoride usually confers hypergolicity, increased density, and lowered vapor pressure whereas the perchloryl fluoride provides oxygen needed for efficient combustion of carbon in the fuel or of certain metal additives. The mixtures are thermally stable and their... 

Heating with oxygen at 400 to 500°C converts the fluoride to oxide ... 

Metal oxides react with oxygen difluoride forming fluorides ... 

In the vapor phase, perfluoro-2-azopropene has been oxidized at high temperatures with oxygen using rubidium fluoride as a catalyst to produce IV-nitrosobis(trifluromethyl)amine, b.p. -3°C to -4°C [34] (Eq. 5). 

Photochemically induced epoxidation of tetrafluoroethene by oxygen with improved yields (71-76%, conversion 21-62%) is achieved in the presence of radical generators such as tri-bromofluoromethane, 1,2-dibromotctrafluorocthane, ethyl nitrite or 1 H, /F,5//-octafluoropen-tyl nitrite.36 The oxidation of tetrafluoroethene with oxygen can also be catalyzed with bis(trifluoromethyl)diazene an undistillable viscous oil with peroxide composition is formed initially which can be quantitatively converted into carbonyl fluoride when heated.37-38... 

Chlorotrifluoroethene (22) is oxidized by oxygen to chlorodifluoroacetyl fluoride (24), which is probably formed by rearrangement of the initially formed unstable chlorotri-fluorooxirane (23).41 The epoxide 23 can be prepared at low temperatures,42 while under irradiation of the reaction mixture with UV light the yield of the epoxide is low and the formation of the acid fluoride is preferred.43,44 Similar results are obtained for l,l-dichloro-2,2-di-fluoroethene (25a).44... 

A more recent oxidation of hexafluoropropene (29) with oxygen over silica gel gives epoxide 30 in 79% yield.49 Among oxidations of 29 in solution, a highly selective continuous electrochemical method for the industrial production of 30 has been reported.50 This process is carried out in aqueous acetic acid/nitric acid/hydrogen fluoride on a lead(IV) oxide anode. 

FLUORINE. CAS 7782-41-4], Chemical element symbol F. at. no. 9. at. wt. 18.9984, periodic table group 17 (halogens), mp -2l9,62nC, bp - 188.1°C. density 1.696 g/l (gas at 0CC, 1.108 g/cm (liquid at bp). Fluorine is a pale yellow gas, poisonous, very reaclive. combines with most other elements in the dark, except it does not combine readily with oxygen. Critical pressure is 55 atm critical temperature is -129.2 C. First identified by Scheele in 1771. but not isolated until 1886 by Moissan who electrolyzed fused potassium hydrogen fluoride in a platinum apparatus. Fluorine is a high-tonnage chemical, used mainly in the production of fluorides, in the synthesis of fluorocarbons, and us rut oxidizer for rocket fuel. 

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