Benzenesulfonyl chloride

Benzenesulfonyl chloride is an organosulfur compound with the formula C₆H₅SO₂Cl. It is a colourless viscous oil that dissolves in organic solvents, but reacts with compounds containing reactive N-H and O-H bonds. It is mainly used to prepare sulfonamides and sulfonate esters by reactions with amines and alcohols, respectively.^[1] The closely related compound toluenesulfonyl chloride is often preferred analogue because it is a solid at room temperature and easier to handle.

Benzenesulfonyl chloride

Names
Preferred IUPAC name Benzenesulfonyl chloride
Identifiers
CAS Number	98-09-9 Y
3D model (JSmol)	Interactive image
ChemSpider	7091
ECHA InfoCard	100.002.397
PubChem CID	7369
UNII	OI9V0QJV9N Y
CompTox Dashboard (EPA)	DTXSID1026619
InChI InChI=1S/C6H5ClO2S/c7-10(8,9)6-4-2-1-3-5-6/h1-5H Key: CSKNSYBAZOQPLR-UHFFFAOYSA-N InChI=1/C6H5ClO2S/c7-10(8,9)6-4-2-1-3-5-6/h1-5H Key: CSKNSYBAZOQPLR-UHFFFAOYAR
SMILES C1=CC=C(C=C1)S(=O)(=O)Cl
Properties
Chemical formula	C6H5ClO2S
Molar mass	176.62
Appearance	colourless liquid
Density	1.384 g/mL at 25 °C(lit.)
Melting point	13 to 14 °C (55 to 57 °F; 286 to 287 K)
Solubility in water	reacts
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Production

The compound is prepared by the chlorosulfonation of benzene:

C₆H₆ + 2SHO₃SCl → C₆H₅SO₂Cl + HCl + SO₃

Benzenesulfonic acid is an intermediate in this conversion. Diphenylsulfone is a side product.

Benzenesulfonyl chloride can also be prepared by treating benzenesulfonate salts with phosphorus oxychloride.^[2]

Reactions

Benzenesulfonyl chloride is an electrophilic reagent. It hydrolyzes with heat but is stable toward cold water.^[2] Amines react to give sulfonamides. This reaction is the basis of the Hinsberg test for amines.^[3]