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4-toluenesulfonyl chloride

4-Toluenesulfonyl chloride
P-Toluenesulfonyl chloride structure.svg
Tosyl-chloride-3D-vdW.png
Names
IUPAC name
4-methylbenzenesulfonyl chloride
Other names
Tosyl chloride, p-toluenesulfonyl chloride, p-TsCl, TsCl
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.002.441
PubChem CID
Properties
C7H7ClO2S
Molar mass 190.65 g/mol
Appearance White solid
Melting point 65 to 69 °C (149 to 156 °F; 338 to 342 K)
Boiling point 134 °C (273 °F; 407 K) at 10 mmHg
Hydrolysis
Hazards
Main hazards Releases acid
NFPA 704
Flammability code 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g., canola oil Health code 3: Short exposure could cause serious temporary or residual injury. E.g., chlorine gas Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazards (white): no codeNFPA 704 four-colored diamond
Flash point 128 °C (262 °F; 401 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

4-Toluenesulfonyl chloride (p-toluenesulfonyl chloride, toluene-p-sulfonyl chloride) is an organic compound with the formula CH3C6H4SO2Cl. This white, malodorous solid is a reagent widely used in organic synthesis. Abbreviated TsCl or TosCl, it is a derivative of toluene and contains a sulfonyl chloride (-SO2Cl) functional group.

In characteristic manner, TsCl converts alcohols (abbreviated ROH) into the corresponding toluenesulfonate esters, or tosyl derivatives ("tosylates"):

Tosylates can be cleaved with lithium aluminium hydride:

Thus, tosylation followed by reduction allows for removal of a hydroxyl group.

Likewise, TsCl is used to prepare sulfonamides from amines:

The resulting sulfonamides are non-basic and, when derived from primary amines, are even acidic.

The preparation of tosyl esters and amides are conducted in the presence of a base, which absorbs hydrogen chloride. The selection of the base is often crucial to the efficiency of tosylation. Typical bases include pyridine and triethylamine. Unusual bases are also used; for example, catalytic amounts of trimethylammonium chloride in the presence of triethylamine is highly effective by virtue of the trimethylamine.

Being a widely available reagent, TsCl has been heavily examined from the perspective of reactivity. It is used in dehydrations to make nitriles, isocyanides and diimides. In an unusual reaction focusing on the sulfur center, zinc reduces TsCl to the sulfinate, CH3C6H4SO2Na.

TsCl is inexpensively available for laboratory use. It is a by-product from the production of o-toluenesulfonyl chloride (a precursor for the synthesis of saccharin), via the chlorosulfonation of toluene:


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