Disulfuryl fluoride

This purification process is particularly important if the imidodisulfuryl fluoride is to be used in the preparation of fluoroimidodisulfuryl fluoride since the fluorination of imido-disulfuryl fluoride which contains small amounts of fluorosulfuric acid does not occur under the conditions to be described. However, if imidodisulfuryl fluoride is to be converted to one of the alkali metal salts, this purification step is not necessary. 

Imidodisulfuryl fluoride,f 18.5 g. (0.102 mole), is loaded into a Pyrex U-tube containing a small magnetic stirring bar. The U-tube is attached to the fractionation train on the vacuum line, and the train is flushed with helium. The two adjacent U-tubes are cooled to —78°, and the last U-tube is cooled to —196°. The two —78° traps should be packed with Pyrex helices to ensure efficient trapping. The fluorine tank is opened, and the concentration of fluorine is adjusted to approximately 30%. The helium-diluted fluorine is passed over the surface of the imidodisulfuryl fluoride at ambient temperature and at a flow rate of 150-175 ml./minute for appro.ximately 2 hours or until most of the imidodisulfuryl fluoride has disappeared from the U-tube. After the fluorination is finished, the system is flushed for 15 minutes with helium and then evacuated. The contents of the two —78° traps [crude FN(SOiF)2] are combined. Final purification is achieved by slow fractionation through U-tubes maintained at —33° (bromobenzene slush) and —78°. The former trap retains approximately 1 g. of imidodisulfuryl fluoride the —78° trap collects 15.3 g. (75% yield) of fluoroimido-disulfuryl fluoride. Anal. Calcd. for FN(SO F)2 N, 7.03 S, 32.3 F, 28.6. Found N, 7.11 S, 32.7 F, 28.8. 

Disulfuryl fluoride has been prepared by the following methods (1) by heating sulfur trioxide under pressure with such fluoride... 

Caution. Because disulfuryl fluoride is extremely toxic, the experimerU should he carried out in a well-verUilcUed hood. Several of the reagents involved in the synthesis (fluorosulfuric acid, cyanuric chloride, and sulfuric add) are poisonous and extremely reactive with the skin. It is recommended that protective gloves be worn when these materials are being handled. 

Disulfuryl fluoride is a clear colorless liquid with a boiling point of 51°. Its vapor pressure over the temperature range —28 to 43° follows the equation logioP(mm.) = 8.015— 1662/T. It has an inhalation toxicity of the same order as that of phosgene, and should be handled only in a well-ventilated area. Its thermal decomposition to sulfur trioxide and sulfuryl fluoride is not very appreciable below 200° but is rapid at 400-500°. In the presence of metal fluorides such as ceaum or sodium fluoride, however, its decomposition point is considerably low er. It hydrolyzes rather slowly to give fluorosulfuric acid. It is not very soluble in cold concentrated sulfuric acid or fluorosulfuric acid, but is soluble in acetonitrile, ethyl ether, carbon tetrachloride, monofluorotrichloromethane, and benzene. 

ABSOLUTE ALCOHOL or ABSOLUTE ETHANOL (64-17-5) Forms explosive mixture with air (flash point 55°F/13°C). Reacts, possibly violently, with strong oxidizers, bases, acetic anhydride, acetyl bromide, acetyl chloride, aliphatic amines, bromine pentafluoride, calcium oxide, cesium oxide, chloryl perchlorate, disulfuryl difluoride, ethylene glycol methyl ether. Iodine heptafluoride, isocyanates, nitrosyl perchlorate, perchlorates, platinum, potassium- er -butoxide, potassium, potassium oxide, potassium peroxide, phosphonis(III) oxide, silver nitrate, silver oxide, sulfuric acid, oleum, sodium, sodium hydrazide, sodium peroxide, sulfmyl cyanamide, tetrachlorosilane, i-triazine-2,4,6-triol, triethoxydialuminum tribromide, triethylaluminum, uranium fluoride, xenon tetrafluoride. Mixture with mercury nitrate(II) forms explosive mercury fulminate. Forms explosive complexes with perchlorates, magnesium perchlorate (forms ethyl perchlorate), silver perchlorate. Flow or agitation of substance may generate electrostatic charges due to low conductivity. 

---