Alkylbenzenesulfonates

Sodium dodecylbenzenesulfonate

Names
IUPAC name sodium dodecylbenzenesulfonate
Other names dodecylbenzenesulfonic acid, sodium salt benzenesulfonic acid, dodecyl-, sodium salt sodiumlaurylbenzenesulfonate
Identifiers
CAS Number	25155-30-0 N
Abbreviations	SDBS
ECHA InfoCard	100.042.422
PubChem CID	23662403 Sodium 2-dodecylbenzenesulfonate 23667983 Sodium 3-dodecylbenzenesulfonate 4289524 Sodium 4-dodecylbenzenesulfonate
UNII	554127163Y sodium dodecylbenzenesulfonate (mixed isomers) N
Properties
Chemical formula	C18H29NaO3S
Molar mass	348.48 g·mol−1
Solubility in water	20%
Hazards
GHS pictograms
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N  (what is YN ?)
Infobox references

Sodium dodecylbenzenesulfonates are organic compounds with the formula C₁₂H₂₅C₆H₄SO₃Na. They are colourless salts with useful properties as surfactants. They are usually produced as a mixture of related sulfonates. They are major components of laundry detergent.

Most sodium dodecylbenzenesulfonates are a member of the linear alkylbenzenesulfonates, meaning that the dodecyl group (C₁₂H₂₅) is unbranched. This dodecyl chain is attached at the 4-position of the benzenesulfonate group. Linear dodecyl-4-benzenesulfonate anions can exist in six isomers (ignoring optical isomers), depending on the carbon of the dodecyl group that is attached to the benzene ring. The isomer shown below left is 4-(5-dodecyl)benzenesulfonate (4 indicating the position of the benzene ring, 5 indicating the position on the dodecane chain). Branched isomers, e.g. those derived from tetramerized propylene, are also known (below right) but are not as widely used because they biodegrade too slowly.

4-(5-Dodecyl) benzenesulfonate, a linear dodecylbenzenesulfonate

A branched dodecylbenzenesulfonate, which has been phased out in developed countries.

Further complicating the description of the commercial materials, sodium dodecylbenzenesulfonate is one component of a mixture of compounds that feature variable alkyl chain lengths aside from C12, mainly ranging from C10-C16. Dodecylbenzenesulfonate is considered representative of the entire class of compounds, since the mean number of alkyl carbon atoms in the alkylbenzenesulfonates is 12.

Billions of kilograms are produced annually. Alkylbenzenesulfonates have been prepared by many methods. In the most common route, benzene is alkylated by long chain monoalkenes (e.g. dodecene) using hydrogen fluoride as a catalyst. The purified dodecylbenzenes (and related derivatives) are then sulfonated with sulfur trioxide to give the sulfonic acid. The sulfonic acid is subsequently neutralized with sodium hydroxide.