Pyrosulfuryl chloride

Sulfur trioxide [7446-11-9] reacts with sulfur monochloride to produce pyrosulfuryl chloride [7791-27-7] CISO2OSO2CI. 

Chemical Reactions. Sulfur dichloride reacts with an excess of sulfur trioxide forming pyrosulfuryl chloride ... 

Chemical Properties. Thionyl chloride chemistry has been reviewed (169—173). Significant inorganic reactions of thionyl chloride include its reactions with sulfur trioxide to form pyrosulfuryl chloride and with hydrogen bromide to form thionyl bromide [507-16-4]. With many metal oxides it forms the corresponding metal chloride plus sulfur dioxide and therefore affords a convenient means for preparing anhydrous metal chlorides. 

When the batch is completed, a slight excess of oleum and chlorine is added to reduce to a minimum the residual SCI2. Because thionyl chloride combines readily with sulfur trioxide to form the relatively stable pyrosulfuryl chloride, it is necessary to maintain the concentration of sulfur trioxide in the reaction mass at a low level hence, the addition of oleum to sulfur chloride rather than the reverse. When all of the reactants are added, heat is appHed to the jacket of the reactor and the batch is refluxed until most of the sulfur dioxide, hydrogen chloride, and chlorine are eliminated. The thionyl chloride is then distilled from the reactor. 

Chlorosulfuric acid is miscible with sulfur trioxide, sulfuric acid, and pyrosulfuryl chloride in all proportions. Mixtures with sulfur trioxide are used as smoke-forming agents. The properties of such mixtures have been described (3,15,16). Mixtures of chlorosulfuric acid and pyrosulfuryl chloride form an a2eotrope when distilled (17). 

Strong dehydrating agents such as phosphorous pentoxide or sulfur trioxide convert chlorosulfuric acid to its anhydride, pyrosulfuryl chloride [7791-27-7] S20 Cl2. Analogous trisulfuryl compounds have been identified in mixtures with sulfur trioxide (3,19). When boiled in the presence of mercury salts or other catalysts, chlorosulfuric acid decomposes quantitatively to sulfuryl chloride and sulfuric acid. The reverse reaction has been claimed as a preparative method (20), but it appears to proceed only under special conditions. Noncatalytic decomposition at temperatures at and above the boiling point also generates sulfuryl chloride, chlorine, sulfur dioxide, and other compounds. 

Total acidity and total chlorides can be deterrnined by conventional techniques after hydrolysing a sample. Satisfactory procedures for determining hydrogen chloride and free-sulfiir trioxide are described in the Hterature (18,41). Small amounts of both hydrogen chloride and sulfur trioxide can be found in the same sample because of the equiUbrium nature of the Hquid. Procedures for the direct deterrnination of pyrosulfuryl chloride have also been described (42,43), but are not generally required for routine analysis. Small concentrations of sulfuric acid can be deterrnined by electrical conductivity. 

Pyroprocessing, of Portland cement raw material, 5 488—489 Pyroredox process, 19 678 Pyrosulfuryl chloride, 23 641, 645, 647, 649 Pyrosultones, decomposition of, 23 527 Pyrotechnics... 

The compound is decomposed by water to form sulfuric and hydrochloric acids. Very pure pyrosulfuryl chloride is obtained by distillation in vacuo it boils at 152.5-153CC at 760mm. 

Pyrolusite, in oxidation of sulfurous acid to dithionate ion, 2 168 Pyrophosphates, determination of, in mixtures of phosphates, 3 93 Pyrophosphoric acid, 3 96, 97 Pyrosulfites, alkali metal, 2 162 Pyrosulfuryl chloride, 3 124, 126... 

PYROSULFURYL CHLORIDE see PPR500 PYROSULPHURIC ACID see SOI520 PYROTARTARIC ACID NITRILE see TLR500 PYROTROPBLAU see CMO250 PYROXYLIC SPIRIT see MGB150... 

Ammonium Persulfate 7782-99-2 Sulfurous Acid 7791-27-7 Pyrosulfuryl Chloride... 

Engelbrecht (1953) produced pyrosulfuryl chlorofluoride by the reaction of pyrosulfuryl chloride with silver fluoride at about 80°. The reaction also gave some sulfuryl chlorofluoride. 

Appel cl al. (8) were able to prepare a diammonium salt of (XCIII) by the reaction of pyrosulfuryl chloride, S OsCh or trisulfury fluoride, S30gF2, with ammonia. 

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