Trichloromethanesulfenyl

Physical Properties. Trichloromethanesulfenyl chloride [594-42-3] (perchloromethyl mercaptan, a misnomer but used as the common commercial name), CCl SCl, is a strongly acrid, pale yellow Hquid, boiling at 149°C with some decomposition at atmospheric pressure, 68°C at 6.93 kPa (52... 

The oxidation of trichloromethanesulfenyl chloride by nitric acid or oxidative chlorination in the presence of water yields trichi oromethanesulfonyl chloride [2547-61-7] CCI2SO2CI, which is a lacrimatory soHd (mp 140—142.5°C), which is surprisingly stable to hydrolysis and can be steam-distiUed. 

Tiichloiomethanesulfenyl chloiide can be reduced to thiophosgene by metals in the presence of acid and by various other reducing agents. The sulfur-bonded chlorine of trichloromethanesulfenyl chloride is most easily displaced by nucleophilic reagents, but under some conditions, the carbon-bound chlorines are also reactive (54). 

Trichloromethanesulfenyl chloride can be added across double bonds under either free-radical or cationic-initiated conditions (55,56) ... 

Manufacture. Trichloromethanesulfenyl chloride is made commercially by chlorination of carbon disulfide with the careful exclusion of iron or other metals, which cataly2e the chlorinolysis of the C—S bond to produce carbon tetrachloride. Various catalysts, notably iodine and activated carbon, are effective. The product is purified by fractional distillation to a minimum purity of 95%. Continuous processes have been described wherein carbon disulfide chlorination takes place on a granular charcoal column (59,60). A series of patents describes means for yield improvement by chlorination in the presence of dihinctional carbonyl compounds, phosphonates, phosphonites, phosphites, phosphates, or lead acetate (61). 

Shipment and Storage. Much of the trichloromethanesulfenyl chloride produced is used captively. However, it can be shipped in dmms. Standard materials for storage and handling are nickel. Monel, and glass. Trichloromethanesulfenyl chloride is not corrosive to nickel and Monel when dry, but cate must be taken to prevent its contact with moisture. 

Economic Aspects. The U.S. manufacture of trichloromethanesulfenyl chloride is carried out by Zeneca, Inc. (Perry, Ohio). Most of the usage is captive. The 1995 price was ca 2.50/kg. 

Analytical Methods. A method has been described for gas chromatographic analysis of trichloromethanesulfenyl chloride as well as of other volatile sulfur compounds (62). A method has been recommended for determining small amounts of trichloromethanesulfenyl chloride in air or water on the basis of a color-forming reaction with resorcinol (63). 

Uses. The principal commercial appHcation for trichloromethanesulfenyl chloride is as an intermediate for the manufacture of fungicides, the most important being captan (A/-(trichlotomethylthio)-4-cyclohexene-l,2-dicatboximide) [133-06-2] (1) and folpet (/V-(tricblorometbyltbio)pbtba1 imide)... 

A commercial soil or seed treatment fungicide, 5-ethoxy-3-trichlotomethyl-l,2,4-thiadia2ole [2593-15-9] (etridia2ole) is prepared from 2-chloro-3-trichloromethyl-l,2,4-thiadia2ole [5848-93-17, a product of trichloromethanesulfenyl chloride and trichloroacetarnidine (68). 

A fluorinated analogue, CFCI2SCI, is made in Europe from trichloromethanesulfenyl chloride and is used for production of the fungicides dichlorofluanid [1085-98-9] (3) and tolylfluanid [731-27-1] (4) (69) ... 

Trichloromethanesulfenyl chloride has also been used for the preparation of lubricant additives (see Lubrication and lubricants). Some higher homologues and analogues of trichloromethanesulfenyl chloride have been reported, ie, trichlorovinylsulfenyl chloride [19411-15-5] 1,1,2,2-tetrachloroethanesulfenyl chloride [1185-09-7] 1,2,2,2-tetrachloroethanesulfenyl chloride [920-62-7] and pentachloroethanesulfenyl chloride [5940-94-3] (70—74). A commercial fungicide, Captafol [2425-06-17, is the reaction product of 1,1,2,2-tetrachloroethanesulfenyl chloride with tetrahydrophthalimide (75). 

Trichloromethanesulfenyl chloride is useful in the preparation of various series of sulfur-containing heterocycles. A commercially significant example is the preparation of l,2,4-thiadia2oles. 

Several related derivatives have also been utilized in this type of synthesis. Imino-chloromethanesulfenyl chlorides (184), prepared by the controlled addition of chlorine to isothiocyanates, react with amidines (161) to give 1,2,4-thiadiazolines (185) (71T4117). Chlorocarbonylsulfenyl chloride (186), prepared by the hydrolysis of trichloromethanesulfenyl chloride with sulfuric acid, reacted with ureas, thioureas and guanidines to give 1,2,4-thiadiazolidine derivatives (187) <70AG(E)54, 73CB3391). 

Trichloromethanesulfenyl chloride is a sulfenyl chloride that does not form a thiolsulfinate upon hydrolysis, however. Instead it gives the sulfine C12C=S=0 (Silhanek and Zbirovsky, 1969) because trichloromethanesulfenic acid loses HC1 (13) faster than it undergoes any other reaction. 

Preparation. Thiophosgene forms from the reaction of carbon tetrachloride with hydrogen sulfide, sulfur, or various sulfides at elevated temperatures. Of more preparative value is the reduction of trichloromethanesulfenyl chloride [594-42-3] by various reducing agents, eg, tin and hydrochloric acid, stannous chloride, iron and acetic acid, phosphoms, copper, sulfur dioxide with iodine catalyst, or hydrogen sulfide over charcoal or silica gel catalyst (42,43). 

The reaction of trichloromethanesulfenyl chloride (440) with amidines (439) and mild base is a general preparation for 5-chloro-l,2,4-thiadiazoles (441) (65AHC(5)119). Iminochloromethanesulfenyl chlorides (442 from RNCS + C12) react with amidines such as PhC(NH)NHR to give 1,2,4-thiadiazo-lines (443) (71T4117). Chlorocarbonylsulfenyl chloride (444) (prepared from trichloromethanesulfenyl... 

Trichloromethanesulfenyl chloride (98) converts 2-aminopyridine (97) into the intermediate sulfenamide (99) which with an aromatic amine cyclizes to (101), probably via the intermediate (100) (75JOC2600). 

The sulfenyl phthalimides are one of the oldest groups of fungicides and are effective, safe and persistent (B-77MI10706). Captan (59) is cheaply made from the Diels-Alder adduct of butadiene and maleic anhydride, followed by conversion to the imide and reaction with trichloromethanesulfenyl chloride. Folpet (60) and captafol (61) are similar in structure. 

The preparations of 1,2,4-thiadiazoles and 1,2,4-thiadiazolidines from thioureas are well known and have been summarized in three reviews those of Bambas,188 Sherman,189 and Kurzer.170 Contained in these reviews are discussions of the controversies that surrounded some of the products, notably Hector s bases, which resulted from oxidation of substituted thioureas.171,172 Subjects covered in the above reviews, but too extensive to outline in detail here, are the oxidation of amidinothioureas to 3,5-diamino-1,2,4-thiadiazoles (71),173,174 the oxidation of phenylthiourea175 and of substituted amidinothioureas176 to 3,5-diimino-l,2,4-thiadiazolidines (72, Hector s bases), the reaction of thiopseudoureas with trichloromethanesulfenyl chloride to form 3-alkylthio-5-chloro-l,2,4-thiadiazoles (73),177 the reaction of thiopseudoureas with sodium thiocyanate and bromine178 and the oxidation... 

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