Reaction with oxygen difluoride

Photolysis of OFj in the presence of carbonyl sulfide/dioxygen mixtures results in the formation of F,SO and CO. If, however, irradiation is continued after total conversion of the COS, the products SOF, SO,F, COF, CF3OF and (CF3),0, were formed [1925]. 

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Uracil gives mainly 5,5-difluorobarbituric acid (19) accompanied by 5-fluorouracil in its reaction with oxygen difluoride.23... 

Mixtures of silica gel and the liquid difluoride sealed in tubes at 334 mbar exploded above -196°C, presence of moisture rendering the mixture shock-sensitive at this temperature [1], Reaction of oxygen difluoride with silica, alumina, molecular sieve or similar surface-active solids is exothermic, and under appropriate conditions may be explosive [2], A quartz fibre can be ignited in the difluoride [3],... 

Reaction of fluorine with an aqueous alkah solution is complex and depends on reaction conditions. A major product of such reaction is oxygen difluoride, OF2. In cold alkah solution, the products constitute metal fluoride, oxygen difluoride, water, and oxygen ... 

Very dangerous fire hazard when exposed to heat, flame, or oxidizers. Moderately explosive when exposed to heat or flame. Explodes on contact with oxygen difluoride nitrogen trichloride bromine pentafluoride chlorine trifluoride dichlorine oxide silver fulminate. Potentially explosive reaction with copper + oxygen. Explosive reaction when heated with perchloryl fluoride (above 100°C), oxygen (above 280°C). Reacts with 4-bromobenzenediazonium chloride to form an explosive product. 

The fluorination of adamantane and its derivatives can also be achieved with oxygen difluoride in the presence of sodium hydrogen carbonate as a hydrogen fluoride trap however, this reaction is complicated by competing oxidation.22 When the fluorination of adamantane is performed with cesium fluoroxysulfate, a mixture of monofluorinated products 4 and 5 arising from fluorination at tertiary and secondary sites, respectively, and difluorinated product 6 is obtained.23 The thermally initiated fluorination of adamantane using xenon difluoride gives a similar mixture but includes a small amount of trifluoride 7.24 25... 

EXPLOSION and FIRE CONCERNS noncombustible solid in bulk form flammable gas as dust or in powder form finely dispersed particles form explosive mixtures in air reacts with oxygen difluoride causing fire hazard violent reaction with bromine trifluoride, chlorine trifluoride and bromine pentafluoride in case of fire in the surroundings, all extinguishing agents are suitable for firefighting purposes. 

Water. Fluorine reacts with water to form hydrofluoric acid [7664-39-3] HF, and oxygen difluoride [7783 1-7] OF2. In dilute (<5%) caustic solutions, the reaction proceeds as follows ... 

In aqueous solution, OF2 oxidizes HCl, HBr, and HI (and thek salts), Hberating the free halogens. Oxygen difluoride reacts slowly with water and a dilute aqueous base to form oxygen and fluorine. The rate of this hydrolysis reaction has been determined (23). 

Analytical Procedures. Oxygen difluoride may be determined conveniently by quantitative appHcation of k, nmr, and mass spectroscopy. Purity may also be assessed by vapor pressure measurements. Wet-chemical analyses can be conducted either by digestion with excess NaOH, followed by measurement of the excess base (2) and the fluoride ion (48,49), or by reaction with acidified KI solution, followed by measurement of the Hberated I2 (4). 

Oxygen difluoride reacts with many common metals forming fluorides. The reaction stops when the metal surface is covered with a protective layer of fluoride ... 

Oxygen difluoride may be analyzed by GC, GC/MS, IR, and NMR methods. The compound may be identified by GC/MS, the characteristic mass ions are 54, 38 and 35. The compound can be measured quantitatively by wet methods based on its strong oxidizing ability (see Reactions). It liberates I2 from an acidified solution of potassium iodide and the liberated I2 can be measured by iodometric titration using Na2S20s titrant and starch indicator. Alternatively, the compound may he treated with a measured amount of excess NaOH and the unreacted excess NaOH measured hy titrating against a standard solution of HCl. Also, the fluoride ion, F, may he measured by fluoride selective electrode. 

The reaction of fluorine with water, producing hypofluorous acid (HOF) and subsequently oxygen difluoride (OF2), has been the subject of intensive study over the last fifty years.1 Additionally, hypofluorous acid in acetonitrile has been characterized.5 The reagents are potentially explosive and present a toxicity hazard similar to fluorine therefore, work should be carried out in an efficient hood and proper safety equipment is required. It was established in the earliest investigations that the reaction of hypofluorous acid with alkenes in nonpolar solvents gives fluoro hydrins, e.g. 1, in high yield.6 However, it is now clear that epoxides are initially formed in acetonitrile7 and 1,2-epoxycyclohexane (2) is formed in reactions with cyclohexene in various solvents.5... 

Oxygen difluoride was first synthesized in 1927 and several publications deal with its preparation.16 19 Oxygen difluoride transforms various aliphatic amines to nitroso compounds 14 in low-temperature reactions.20... 

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... 

Oxygen difluoride oxidizes (perfluoroalkyl)imidosulfurous difluorides (substituted sulfilimines) 19 to the corresponding imidosulluryl difluoride derivatives 20 in high yield under irradiation with UV light.306 In all the reactions carried out, the A, V -bis(pcrfluoroalkyl)diimidosulfuryl difluorides 21 were the byproducts.306... 

Xenon difluoride reacts (Scheme 2) with oxygen-containing molecules and FXeOR and Xe(OR)2 are formed by reactions with acids7, while S03 is also suggested as a reacting species under various conditions8,9. 

The AH° of reaction at 298.16° K. of oxygen difluoride with hydrogen was measured using a Parr fluorine combustion bomb modified to contain a metal ampoule employing a burst diaphragm. This modification permits heat of reaction measurements on systems where reaction occurs spontaneously upon mixing the reactants. The AH° of the reaction OFt - HtO + 2HF (infinite dilution) was found... 

Oxygen difluoride reacts rapidly with selected alkenes at low temperatures however, per-fliioroalkenes are less reactive than the corresponding alkylalkenes and require either thermal or ultraviolet activation." The oxidation, which is a homogeneous chain reaction," of hexa-fluoropropene, tetrafluorocyclopropene, and pcrfluorobut-2-ene all give a variety of products such as carbon tetrafluoridc, carbonyl difluoride, hexafluoroethane, oxiranes, and other oxidation products." This reaction is not useful for preparative organic work. 

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