Sulfur dioxide dichloride

Solvent Treatment. Solvent processes can be divided into two main categories, solvent extraction and solvent dewaxing. The solvent used in the extraction processes include propane and cresyHc acid, 2,2 -dichlorodiethyl ether, phenol (qv), furfural, sulfur dioxide, benzene, and nitrobenzene. In the dewaxing process (28), the principal solvents are benzene, methyl ethyl ketone, methyl isobutyl ketone, propane, petroleum naphtha, ethylene dichloride, methylene chloride, sulfur dioxide, and iV-methylpyrroHdinone. 

Solvents used for dewaxing are naphtha, propane, sulfur dioxide, acetone—benzene, trichloroethylene, ethylenedichloride—benzene (Barisol), methyl ethyl ketone—benzene (benzol), methyl -butyl ketone, and methyl / -propyl ketone. Other solvents in commercial use for dewaxing include /V-methylpyrrolidinone, MEK—MIBK (methyl isobutyl ketone), dichloroethane—methylene dichloride, and propfyene—acetone. 

Chemical Properties. The chemistry of the sulfur chlorides has been reviewed (141,142). Sulfur monochloride is stable at ambient temperature but undergoes exchange with dissolved sulfur at 100°C, indicating reversible dissociation. When distilled at its atmospheric boiling point, it undergoes some decomposition to the dichloride, but decomposition is avoided with distillation at ca 6.7 kPa (50 mm Hg). At above 300°C, substantial dissociation to S2 and CI2 occurs. Sulfur monochloride is noncombustible at ambient temperature, but at elevated temperatures it decomposes to chlorine and sulfur (137). The sulfur then is capable of burning to sulfur dioxide and a small proportion of sulfur trioxide. 

The equiHbrium constant is 0.013 at 18°C. Sulfur dichloride reacts violently with water, forming hydrogen chloride, sulfur dioxide, hydrogen sulfide, sulfur, and a mixture of thionic acids. 

Using a 0—10% excess of chlorine and 100% excess of sulfur dioxide, conversions of around 50% are obtained. The Hquids in the reaction product are condensed and separated, the sulfur mono- and dichloride are returned for further reaction, and the excess gases are also recycled, producing an ultimate yield near 100% on all reactants. 

At present, thionyl chloride is produced commercially by the continuous reaction of sulfur dioxide (or sulfur trioxide) with sulfur monochloride (or sulfur dichloride) mixed with excess chlorine. The reaction is conducted in the gaseous phase at elevated temperature over activated carbon (178). Unreacted sulfur dioxide is mixed with the stoichiometric amount of chlorine and allowed to react at low temperature over activated carbon to form sulfuryl chloride, which is fed back to the main thionyl chloride reactor. 

A number of processes have been devised for purifying thionyl chloride. A recommended laboratory method involves distillation from quinoline and boiled linseed oil. Commercial processes involve adding various high boiling olefins such as styrene (qv) to react with the sulfur chlorides to form adducts that remain in the distillation residue when the thionyl chloride is redistilled (179). Alternatively, sulfur can be fed into the top of the distillation column to react with the sulfur dichloride (180). Commercial thionyl chloride has a purity of 98—99.6% minimum, having sulfur dioxide, sulfur chlorides, and sulfuryl chloride as possible impurities. These can be determined by gas chromatography (181). 

The reaction of the 3,3-disubstituted-l,2-alkadienephosphonic dichlorides with alkylsulphenyl chlorides afforded, along with 2,5-dihydro-l,2-oxaphosphole-2-oxide derivatives, 1,2-adducts also. The use of sulfur dioxide in this reaction promoted the formation of the oxaphosphole product (Scheme 35) [22, 44, 71-73, 87-92],... 

Sulfides Sulfur Sulfur dioxide Sulfuric acid Sulfuryl dichloride Acids, powerful oxidizers, moisture Oxidizing materials, halogens Halogens, metal oxides, polymeric tubing, potassium chlorate, sodium hydride Chlorates, metals, HC1, organic materials, perchlorates, permanganates, water Alkalis, diethyl ether, dimethylsulfoxide, dinitrogen tetroxide, lead dioxide, phosphorus... 

While stirred, 1-heptene (9.8 g, 0.1 mol) was added at 20°C to a suspension of phosphorus pentachloride (41.7 g, 0.2 mol) in dimethyl-dicholorsilane (100 ml). The reaction mixture was stirred at 20°C for 3 h and cooled to -10°C. Sulfur dioxide dried over phosphorus pen-toxide was bubbled into the reaction mixture until complete dissolution of the intermediate complex was observed. After evaporation of solvent, the residue was vacuum distilled to give pure 2-chlorohept-l-ylphosphonic dichloride (22.1 g, 88%). 

The effect of initiators (diluted sulfuric acid, chlorine dioxide, sulfur dioxide or disulfur dichloride) on ignition of mixtures of barium, lead or potassium chlorates with sulfur was examined [1] Presence of copper ion or metal (e.g. from a sieve) may also lead to explosion of such mixtures [2], A review of hazards of sulphur/chlorate mixtures in the firework industry has been published [3],... 

The product 303 from disulfur dichloride and 2,3-dimethylbuta-l,3-diene rearranges spontaneously to the tetrahydrothiophene 304 (equation 159)150. The reaction of liquid sulfur dioxide with conjugated dienes 305 (e.g. butadiene, isoprene) results in cyclic sulfones which dissociate into their components on heating (equation 160)151 152. 

Styrylphosphonic dichloride has been prepared by the addition of phosphorus pentachloride to styrene with subsequent reaction of the adduct with phosphorus pentoxide or sulfur dioxide. ... 

The compound decomposes above 140°C to form sulfur dioxide, chlorine and disulfur dichloride ... 

Potassium phosphinate, 4453 Sodium disulfite, 4802 Sodium dithionite, 4801 Sodium hydride, 4438 Sodium hypoborate, 0164 Sodium phosphinate, 4467 Sodium thiosulfate, 4798 Sulfur dioxide, 4831 Tetraphosphorus hexaoxide, 4861 Tin(II) chloride, 4064 Tin(II) fluoride, 4325 Titanium trichloride, 4152 Titanium(II) chloride, 4111 Tungsten dichloride, 4113 Vanadium dichloride, 4112 Vanadium trichloride, 4153 Zinc, 4921... 

Methyl Bromide Methylene Chloride Methyl Formate Napthalene Perchloroethylene Propylene Dichloride Sulfur Dioxide Tetrachlorethane Trichloroethylene... 

Sulfinic esters, aromatic, by oxidation of disulfides in alcohols, 46, 64 Sulfonation of D,L-camphor to d,l-10-camphorsulfonic acid, 46,12 Sulfoxides, table of examples of preparation from sulfides with sodium metaperiodate, 46,79 Sulfur dioxide, reaction with styrene phosphorus pentachloride to give styrylphosphonic dichloride, 46,... 

Molybdenum oxide trichloride has been prepared by heating molybdenum(VI) oxide or molybdenum dioxide dichloride with molybdenum(V) chloride. Molybdenum(VI) oxide tetrachloride is a by-product of the latter reaction.1 It was also prepared by the sealed-tube reaction of liquid sulfur dioxide with molybdenum (Y) chloride2 and by the thermal decomposition of molybdenum oxide tetrachloride in a stream of nitrogen. In the following procedure, it is prepared by reducing molybdenum oxide tetrachloride with refluxing chlorobenzene.4... 

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