Potassium fluorosulfite

Potassium fluorosulfite can be prepared by the reaction of potassium fluoride with sulfur dioxide in an autoclave or by grinding potassium fluoride in a ball mill under an atmosphere of sulfur dioxide. The reaction can be carried out by treating potassium fluoride with a solution of sulfur dioxide in dimethyl sulfoxide or in tetramethylene sulfone (tetrahydrothiophene 1,1-dioxide, Sulfolane) without resorting to costly apparatus and with practically quantitative yields. The starting materials must, in every case, be completely anhydrous. 

One hundred fifty grams of potassium fluoride (not the hydrate) is dried by heating over a Bunsen burner in a stainless-steel evaporating dish and is then ground for 6 to 8 hours in a ball mill containing stainless-steel ball bearings or chrome alloy steel bearings, 1 in. in diameter. 

One hundred forty-five grams (2.5 mols) of the resultant potassium fluoride is placed in a 250-ml. flask and heated under high vacuum to 150 to 200° to free it completely from water. 

The powder is then placed in a protective atmosphere of dry air in a 2-1. three-necked flask fitted with a stirrer, a dropping funnel, and a safety wash bottle containing concentrated sulfuric acid. One hundred fifty milliliters of pure anhydrous dimethyl sulfoxide is added to the powdered material in the flask. Then a solution containing 200 g. (3.1 mols) of sulfur dioxide in 600 ml. of dimethyl sulfoxide is added dropwise, slowly, with stirring. Gaseous sulfur dioxide may be added to the solvent through a gas dispersion tube while weighing the container frequently on a triple-beam balance. 

After centrifugation, about 75% of the original solvent (dimethyl sulfoxide) and a significant amount of dissolved excess sulfur dioxide can be recovered. This dilute solution can be enriched with more sulfur dioxide and used again. If the ether solutions of dimethyl sulfoxide are not worked up, there is a loss of 1 mol of dimethyl sulfoxide per mol of potassium fluorosulfite. 

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See Niobium(V) chloride and hexachloroniobates(V), synthesis 23 Potassium fluorosulfite, synthesis 28... 

Previous methods for the preparation of sulfuryl fluoride have involved either the reaction of elemental fluorine with a variety of sulfur-oxygen compounds or the reaction of silver fluoride with sulfur dioxide. A very simple procedure for the preparation of sulfuryl fluoride in good yield involves the reaction of potassium fluorosulfite with chlorine gas. ... 

The reaction of chlorine with an appropriate amount of potassium fluorosulfite (synthesis 28) is carried out in a... 

If the upper half of the reaction tube is heated to 170 to 180° by means of an electric tube furnace, the sulfuryl chloride fluoride (formed in the lower half of the tube) reacts with potassium fluorosulfite in the heated portion of the tube to produce sulfuryl fluoride. The reaction is substantially complete when the narrow warm zone characteristic of the formation of sulfuryl chloride fluoride has reached the externally heated portion of the tube, where the SO2CIF SO2F2 transformation takes place. A mixture of the two liquid products is formed in the flask surrounded with Dry Ice the two products can be separated easily by fractional distillation and may be identified by their infrared or mass spectra. ... 

Potassium fluorosulfite is a colorless crystalline powder which, because of hydrolysis, smells of sulfur dioxide and which must necessarily be stored under protection from moisture. The following relationship applies for the sulfur dioxide vapor pressure over potassium fluorosulfite ... 

Chemically, potassium fluorosulfite behaves as though it were activated potassium fluoride. At only slightly elevated temperatures, potassium fluorosulfite converts carboxylic chlorides and the chlorides of boron, phosphorus, and sulfur to the corresponding fluorides. ... 

The phosphonitrilic fluorides do not result from the interaction of ammonium fluoride with phosphorus pentachloride ammonium hexa-fluorophosphate is formed instead (47). They may be prepared indi-j ectly by the reaction of potassium fluorosulfite with the chlorides at 100°-120° (75),... 

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