Oxygen difluoride

Toxicology. Oxalic acid is an irritant of the eyes, mucous membranes, and skin inhalation or ingestion may result in kidney damage, and in severe exposures there may be convulsions and death. 

There is little reported information on industrial exposure, although chronic inflammation of the upper respiratory tract has been described in a worker exposed to hot vapor arising from oxalic acid. Ingestion of as little as 5 g has caused fatalities there is rapid onset of shock, collapse, and convulsions. The convulsions are thought to be the result of hypocalcemia due to the calcium-complexing action of oxalic acid, which depresses the level of ionized calcium in body fluids. Marked renal damage from deposition of calcium oxalate may occur. A study of railroad car cleaners with heavy exposure to oxalic acid solutions found an increased incidence of urinary stones. There was a 53% incidence of urolithiasis in exposed workers compared with a rate of 12% in unexposed workers from the same company.  

Gross contact of the hands with solutions of oxalic acid (5.3% and 11.5% in 2 reported cases) used as cleaning solutions caused tingling, burning, soreness, and cyanosis of the fingers.  

Splashes of solutions in the eyes have produced epithelial damage from which recovery has been prompt.  

The single oral LDso for a 5% by weight oxalic acid solution was 9.5 ml/kg for male rats and 7.5 ml/kg for females. Applied to rabbit skin, a single exposure of 20g/kg of the solution was not lethal. 

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Oxygen difluoride, OFj, is obtained when gaseous fluorine is passed through very dilute (27 ) caustic soda solution ... 

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 the presence of excess caustic, the oxygen difluoride is gradually reduced to oxygen and fluoride ... 

Oxygen. Oxygen does not react directly with fluorine under ordinary conditions, although ia addition to oxygen difluoride, three other oxygen fluorides are known (29). Dioxygen difluoride [7783-44-0] 2 2 difluoride [16829-28-0] 3 2 tetraoxygen difluoride [12020-93-8] 4 2 ... 

In a caustic scmbbing system, caustic potash, KOH, is preferred to caustic soda, NaOH, because of the higher solubiUty of the resulting potassium fluoride. Adequate solution contact and residence time must be provided in the scmb tower to ensure complete neutralization of the intermediate oxygen difluoride, OF2. Gas residence times of at least one minute and caustic concentrations in excess of 5% are recommended to prevent OF2 emission from the scmb tower. 

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). 

Nitric oxide and OF2 inflame on contact emission and absorption spectra of the flame have been studied (24). Oxygen difluoride oxidizes SO2 to SO, but under the influence of uv kradiation it forms sulfuryl fluoride [2699-79-8] SO2F2, and pyrosulfuryl fluoride [37240-33-8] S20 F2 (25). Photolysis of SO —OF2 mixtures yields the peroxy compound FSO2OOF [13997-94-9] (25,26). 

Oxygen Difluoride as a Source of the OF Radical. The existence of the OF radical [12061 -70-0] was first reported in 1934 (27). This work was later refuted (28). The OF radical was produced by photolysis of OF2 in a nitrogen or argon matrix at 4 K. The existence of the OF species was deduced from a study of the kinetics of decomposition of OF2 and the kinetics of the photochemical reaction (25,26) ... 

Carbonyl fluoride, COF2, and oxygen difluoride react in the presence of cesium fluoride catalyst to give bis(trifluorylmethyl)trioxide [1718-18-9] CF OOOCF (31). CF OOF has been isolated from the reaction in the presence of excess OF2 (32). 

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). 

Handling and Safety Factors. Oxygen difluoride can be handled easily and safely in glass and in common metals such as stainless steel, copper, aluminum. Monel, and nickel, from cryogenic temperatures to 200°C (4). At higher temperatures only nickel and Monel are recommended. The compatibihty of OF2 with process equipment depends largely on the cleanliness of the equipment contaminants such as dkt, moisture, oil, grease, scale... 

Oxygen difluoride must be regarded as a highly poisonous gas, somewhat more toxic than fluoriae. It has a foul odor with a limit of detectabiUty of 0.1—0.5 ppm. Repeated exposure of rats to 0.5 ppm OF2 produced death repeated exposure to 0.1 ppm, however, caused no discernible effects. 

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). 

Bismuth pentafluoride is an active fluorinating agent. It reacts explosively with water to form ozone, oxygen difluoride, and a voluminous chocolate-brown precipitate, possibly a hydrated bismuth(V) oxyfluoride. A similar brown precipitate is observed when the white soHd compound bismuth oxytrifluoride [66172-91 -6] BiOF, is hydrolyzed. Upon standing, the chocolate-brown precipitate slowly undergoes reduction to yield a white bismuth(Ill) compound. At room temperature BiF reacts vigorously with iodine or sulfur above 50°C it converts paraffin oil to fluorocarbons at 150°C it fluorinates uranium tetrafluoride to uranium pentafluoride and at 180°C it converts Br2 to bromine trifluoride, BrF, and bromine pentafluoride, BrF, and chlorine to chlorine fluoride, GIF. It apparently does not react with dry oxygen. 

Chemical Reactivity - Reactivity with Water Reacts with water to form hydrogen fluoride, oxygen and oxygen difluoride Reactivity with Common Materials Reacts violently with all combustible materials, except the metal cylinders in which it is shipped Stability During Transport Stable Neutralizing Agents for Acids and Caustics Not pertinent Polymerization Not pertinent Inhibitor of Polymerization Not pertinent. 

Pt is attacked by bromine trifluoride at 280° in the presence of K fluoride (Ref 5). Finely divided Pt and some other metals will cause a mixt of Hj and 02 to explu at ordinary temps (Ref 1). A little Pt black dropped into a hydrogen peroxide soln can cause an expln (Ref 2). Pt and molten Ii react violently at 540° 20° (Ref 7), and an incandescent reaction occurs when it is wanned gently in gaseous oxygen difluoride (Ref 6). The decompn of 92% per-monosulfuric acid is expl in the presence of smooth or finely divided Pt (Ref 3). The re-. acting mass formed by the mixt of P and Pt can become incandescent when heated (Ref 8). Dry, used Pt catalyst has exWd while being screened (Ref 4)... 

Self-Test 2.8B Suggest a likely structure for the oxygen difluoride molecule. Write its Lewis structure and formal charges. 

Koepke, J.W. Jolly, W.L. The Core Binding Energies of Oxygen Difluoride J. Electron Spectros. Relal. Phenom. 1976, 9, 413-416. 

Methyl isocyanate Nickel tetracarbonyl Nitrogen oxides Oxygen difluoride Pentaborane Phosgene... 

The acidic properties of methanesulphonic acid that have just been mentioned have been responsible for two other accidents. When this acid is contact with methyl and vinyl oxide, this caused the latter to polymerise violently. The electrolysis of methanesulphonic acid with an aqueous solution of hydrogen fluoride gives rise to a violent detonation that was put down to the formation of oxygen difluoride that is explosive. 

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