In
inorganic chemistry
Inorganic chemistry deals with synthesis and behavior of inorganic and organometallic compounds. This field covers chemical compounds that are not carbon-based, which are the subjects of organic chemistry. The distinction between the two disc ...
, sulfonyl halide groups occur when a
sulfonyl ()
functional group
In organic chemistry, a functional group is a substituent or moiety in a molecule that causes the molecule's characteristic chemical reactions. The same functional group will undergo the same or similar chemical reactions regardless of the res ...
is
singly bonded to a
halogen atom. They have the general
formula , where X is a halogen. The
stability
Stability may refer to:
Mathematics
* Stability theory, the study of the stability of solutions to differential equations and dynamical systems
** Asymptotic stability
** Linear stability
** Lyapunov stability
** Orbital stability
** Structural st ...
of sulfonyl halides decreases in the order
fluoride
Fluoride (). According to this source, is a possible pronunciation in British English. is an inorganic, monatomic anion of fluorine, with the chemical formula (also written ), whose salts are typically white or colorless. Fluoride salts ...
s >
chloride
The chloride ion is the anion (negatively charged ion) Cl−. It is formed when the element chlorine (a halogen) gains an electron or when a compound such as hydrogen chloride is dissolved in water or other polar solvents. Chloride s ...
s >
bromide
A bromide ion is the negatively charged form (Br−) of the element bromine, a member of the halogens group on the periodic table. Most bromides are colorless. Bromides have many practical roles, being found in anticonvulsants, flame-retardan ...
s >
iodide
An iodide ion is the ion I−. Compounds with iodine in formal oxidation state −1 are called iodides. In everyday life, iodide is most commonly encountered as a component of iodized salt, which many governments mandate. Worldwide, iodine def ...
s, all four types being well known. The sulfonyl chlorides and fluorides are of dominant importance in this series.
Structure
Sulfonyl halides have tetrahedral sulfur centres attached to two oxygen atoms, an organic radical, and a halide. In a representative example,
methanesulfonyl chloride, the S=O, S−C, and S−Cl bond distances are respectively 142.4, 176.3, and 204.6 pm.
Sulfonyl chlorides

Sulfonic acid chlorides, or sulfonyl chlorides, are a sulfonyl halide with the general formula .
Production
Arylsulfonyl chlorides are made industrially in a two-step, one-pot reaction from an
arene (in this case,
benzene
Benzene is an organic chemical compound with the molecular formula C6H6. The benzene molecule is composed of six carbon atoms joined in a planar ring with one hydrogen atom attached to each. Because it contains only carbon and hydrogen ato ...
) and
chlorosulfuric acid
Chlorosulfuric acid (IUPAC name: sulfurochloridic acid) is the inorganic compound with the formula HSO3Cl. It is also known as chlorosulfonic acid, being the sulfonic acid of chlorine. It is a distillable, colorless liquid which is hygroscopic an ...
:
:
C6H6 + HOSO2Cl -> C6H5SO3H + HCl
:
C6H5SO3H + HOSO2Cl -> C6H5SO2Cl + H2SO4
The intermediate
benzenesulfonic acid can be chlorinated with
thionyl chloride
Thionyl chloride is an inorganic compound with the chemical formula . It is a moderately volatile, colourless liquid with an unpleasant acrid odour. Thionyl chloride is primarily used as a chlorinating reagent, with approximately per year bein ...
as well. Benzenesulfonyl chloride, the most important sulfonyl halide, can also be produced by treating sodium benzenesulfonate with
phosphorus pentachloride
Phosphorus pentachloride is the chemical compound with the formula PCl5. It is one of the most important phosphorus chlorides, others being PCl3 and POCl3. PCl5 finds use as a chlorinating reagent. It is a colourless, water-sensitive and moist ...
s.
Benzenediazonium chloride reacts with
sulfur dioxide
Sulfur dioxide ( IUPAC-recommended spelling) or sulphur dioxide (traditional Commonwealth English) is the chemical compound with the formula . It is a toxic gas responsible for the odor of burnt matches. It is released naturally by volcanic ...
and
hydrochloric acid
Hydrochloric acid, also known as muriatic acid, is an aqueous solution of hydrogen chloride. It is a colorless solution with a distinctive pungent smell. It is classified as a strong acid. It is a component of the gastric acid in the dig ...
to give the sulfonyl chloride:
:
6H5N2l + SO2 -> C6H5SO2Cl + N2
For alkylsulfonyl chlorides, one synthetic procedure is the
Reed reaction:
:
RH + SO2 + Cl2 -> RSO2Cl + HCl
Reactions
Sulfonyl chlorides react with water to give the corresponding
sulfonic acid:
:
RSO2Cl + H2O -> RSO3H + HCl
These compounds react readily with many other nucleophiles as well, most notably
alcohol
Alcohol most commonly refers to:
* Alcohol (chemistry), an organic compound in which a hydroxyl group is bound to a carbon atom
* Alcohol (drug), an intoxicant found in alcoholic drinks
Alcohol may also refer to:
Chemicals
* Ethanol, one of sev ...
s and
amine
In chemistry, amines (, ) are compounds and functional groups that contain a basic nitrogen atom with a lone pair. Amines are formally derivatives of ammonia (), wherein one or more hydrogen atoms have been replaced by a substituent su ...
s (see
Hinsberg reaction). If the nucleophile is an alcohol, the product is a sulfonate ester; if it is an amine, the product is a
sulfonamide
In organic chemistry, the sulfonamide functional group (also spelled sulphonamide) is an organosulfur group with the structure . It consists of a sulfonyl group () connected to an amine group (). Relatively speaking this group is unreactiv ...
. Using sodium sulfite as the nucleophilic reagent, sulfonyl chlorides convert to the
sulfonate salts, such as . Chlorosulfonated alkanes are susceptible to crosslinking via reactions with various nucleophiles.
[
Sulfonyl chlorides readily undergo Friedel–Crafts reactions with arenes giving sulfones, for example:
:RSO2Cl + C6H6 -> RSO2C6H5 + HCl
The desulfonation of arylsulfonyl chlorides provides a route to aryl chlorides:
:ArSO2Cl -> ArCl + SO2
]1,2,4-Trichlorobenzene
1,2,4-Trichlorobenzene is an organochlorine compound, one of three isomers of trichlorobenzene. It is a derivative of benzene with three chloride substituents. It is a colorless liquid used as a solvent for a variety of compounds and materials.
P ...
is made industrially in this way.
Treatment of alkanesulfonyl chlorides having α-hydrogens with amine bases can give sulfenes, highly unstable species that can be trapped:
:RCH2SO2Cl -> RCH=SO2
Common sulfonyl chlorides
Chlorosulfonated polyethylene (CSPE) is produced industrially by chlorosulfonation of polyethylene. CSPE is noted for its toughness, hence its use for roofing shingles.
An industrially important derivative is benzenesulfonyl chloride. In the laboratory, useful reagents include tosyl chloride, brosyl chloride, nosyl
In organosulfur chemistry, a sulfonyl group can refer either to a functional group found primarily in sulfones, or to a substituent obtained from a sulfonic acid by the removal of the hydroxyl group, similarly to acyl groups. Sulfonyl groups ...
chloride and mesyl chloride.
Sulfonyl fluorides
Sulfonyl fluorides have the general formula RSO2F. "Most, if not all" industrially synthesized perfluorooctanesulfonyl derivatives, such as PFOS
Perfluorooctanesulfonic acid (PFOS) ( conjugate base perfluorooctanesulfonate) is a chemical compound having an eight- carbon fluorocarbon chain and a sulfonic acid functional group and thus a perfluorosulfonic acid. It is an anthropogenic (man ...
, have the sulfonyl fluoride as their precursor.
In the laboratory, sulfonyl fluorides are used in molecular biology as reactive probes. They specifically react with residues based on serine
Serine (symbol Ser or S) is an α-amino acid that is used in the biosynthesis of proteins. It contains an α- amino group (which is in the protonated − form under biological conditions), a carboxyl group (which is in the deprotonated − for ...
, threonine
Threonine (symbol Thr or T) is an amino acid that is used in the biosynthesis of proteins. It contains an α-amino group (which is in the protonated −NH form under biological conditions), a carboxyl group (which is in the deprotonated −COO ...
, tyrosine
-Tyrosine or tyrosine (symbol Tyr or Y) or 4-hydroxyphenylalanine is one of the 20 standard amino acids that are used by cells to synthesize proteins. It is a non-essential amino acid with a polar side group. The word "tyrosine" is from the Gr ...
, lysine
Lysine (symbol Lys or K) is an α-amino acid that is a precursor to many proteins. It contains an α-amino group (which is in the protonated form under biological conditions), an α-carboxylic acid group (which is in the deprotonated &minu ...
, cysteine
Cysteine (symbol Cys or C; ) is a semiessential proteinogenic amino acid with the formula . The thiol side chain in cysteine often participates in enzymatic reactions as a nucleophile.
When present as a deprotonated catalytic residue, s ...
, and histidine
Histidine (symbol His or H) is an essential amino acid that is used in the biosynthesis of proteins. It contains an α-amino group (which is in the protonated –NH3+ form under biological conditions), a carboxylic acid group (which is in the ...
. The fluorides are more resistant than the corresponding chlorides and are therefore better suited to this task.
Sulfonyl bromides
Sulfonyl bromides have the general formula RSO2Br. In contrast to sulfonyl chlorides, sulfonyl bromides readily undergo light-induced homolysis affording sulfonyl radicals, which can add to alkene
In organic chemistry, an alkene is a hydrocarbon containing a carbon–carbon double bond.
Alkene is often used as synonym of olefin, that is, any hydrocarbon containing one or more double bonds.H. Stephen Stoker (2015): General, Organic, an ...
s, as illustrated by the use of bromomethanesulfonyl bromide, BrCH2SO2Br in Ramberg–Bäcklund reaction syntheses.
Sulfonyl iodides
Sulfonyl iodides, having the general formula RSO2I, are quite light-sensitive. Perfluoroalkanesulfonyl iodides, prepared by reaction between silver perfluoroalkanesulfinates and iodine
Iodine is a chemical element with the Symbol (chemistry), symbol I and atomic number 53. The heaviest of the stable halogens, it exists as a semi-lustrous, non-metallic solid at standard conditions that melts to form a deep violet liquid at , ...
in dichloromethane at −30 °C, react with alkenes to form the normal adducts, RFSO2CH2CHIR and the adducts resulting from loss of SO2, RFCH2CHIR. Arenesulfonyl iodides, prepared from reaction of arenesulfinates or arenehydrazides with iodine, can be used as initiators to facilitate the synthesis of poly(methyl methacrylate) containing C–I, C–Br and C–Cl chain ends.
In popular culture
In the episode "Encyclopedia Galactica" of his TV series '' Cosmos: A Personal Voyage'', Carl Sagan
Carl Edward Sagan (; ; November 9, 1934December 20, 1996) was an American astronomer, planetary scientist, cosmologist, astrophysicist, astrobiologist, author, and science communicator. His best known scientific contribution is research on ...
speculates that some intelligent extraterrestrial beings might have a genetic code
The genetic code is the set of rules used by living cells to translate information encoded within genetic material ( DNA or RNA sequences of nucleotide triplets, or codons) into proteins. Translation is accomplished by the ribosome, which links ...
based on polyaromatic sulfonyl halides instead of DNA.
References
{{Functional Groups
Functional groups