The Reed reaction is a
chemical reaction
A chemical reaction is a process that leads to the chemical transformation of one set of chemical substances to another. Classically, chemical reactions encompass changes that only involve the positions of electrons in the forming and breaking ...
that utilizes
light
Light or visible light is electromagnetic radiation that can be perceived by the human eye. Visible light is usually defined as having wavelengths in the range of 400–700 nanometres (nm), corresponding to frequencies of 750–420 t ...
to
oxidize
Redox (reduction–oxidation, , ) is a type of chemical reaction in which the oxidation states of substrate change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is the gain of electrons or ...
hydrocarbon
In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons are examples of group 14 hydrides. Hydrocarbons are generally colourless and hydrophobic, and their odors are usually weak or ...
s to alkyl
sulfonyl chlorides. This reaction is employed in modifying polyethylene to give
chlorosulfonated polyethylene (CSPE), which noted for its toughness.
Commercial implementations
Polyethylene is treated with a mixture of chlorine and sulfur dioxide under UV-radiation. Vinylsulfonic acid can also be prepared beginning with the sulfochlorination of
chloroethane
Chloroethane, commonly known as ethyl chloride, is a chemical compound with chemical formula CH3CH2Cl, once widely used in producing tetraethyllead, a gasoline additive. It is a colorless, flammable gas or refrigerated liquid with a faintly sweet ...
.
Dehydrohalogenation of the product gives vinylsulfonyl chloride, which subsequently is hydrolyzed to give
vinylsulfonic acid
Vinylsulfonic acid is the organosulfur compound with the chemical formula CH2=CHSO3H. It is the simplest unsaturated sulfonic acid. The C=C double bond is a site of high reactivity. Polymerization gives polyvinylsulfonic acid, especially when ...
:
::
::=
::
Mechanism
The reaction occurs via a
free radical
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Biogerontology
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Metabo ...
mechanism. UV-light initiates
homolysis of
chlorine
Chlorine is a chemical element with the symbol Cl and atomic number 17. The second-lightest of the halogens, it appears between fluorine and bromine in the periodic table and its properties are mostly intermediate between them. Chlorine i ...
, producing a pair of chlorine atoms:
Chain initiation:
::::
Cl2 -> \nu2Cl.
Thereafter a chlorine atom attacks the hydrocarbon chain, freeing hydrogen to form
hydrogen chloride
The compound hydrogen chloride has the chemical formula and as such is a hydrogen halide. At room temperature, it is a colourless gas, which forms white fumes of hydrochloric acid upon contact with atmospheric water vapor. Hydrogen chlorid ...
and an
alkyl
In organic chemistry, an alkyl group is an alkane missing one hydrogen.
The term ''alkyl'' is intentionally unspecific to include many possible substitutions.
An acyclic alkyl has the general formula of . A cycloalkyl is derived from a cycloa ...
free radical. The resulting radical then captures
SO2. The resulting
sulfonyl
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 c ...
radical
Radical may refer to:
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attacks another chlorine molecule to produce the desired sulfonyl chloride and a new chlorine atom, which continues the reaction chain.
Chain propagation steps:
::::
+ .Cl -> + HCl
::::
+ SO2 -> R-\dotO2
::::
+ Cl2 -> + Cl.
See also
*
Chain reaction
A chain reaction is a sequence of reactions where a reactive product or by-product causes additional reactions to take place. In a chain reaction, positive feedback leads to a self-amplifying chain of events.
Chain reactions are one way that sys ...
Historical readings
* Reed, C. F. ; ; .
*
*
*
*
References
Substitution reactions
Carbon-heteroatom bond forming reactions
Name reactions
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