Sodium dodecylbenzenesulfonate
Encyclopedia
Sodium dodecylbenzenesulfonate is a series of organic compound
s with the formula C12H25C6H4SO3Na. It is a colourless salt with useful properties as a surfactant
. It is usually produced as a mixture of related sulfonates. It is a major component of laundry detergent
.
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 to the right 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 (see figure to left) but are not as widely used because they biodegrade too slowly.
Further complicating the description of the commercial materials, sodium dodecylbenzenesulfonate is but 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.
as a catalyst. The purified dodecylbenzene
s (and related derivatives) are then sulfonated with sulfur trioxide
to give the sulfonic acid
. The sulfonic acid is subsequently neutralized with sodium hydroxide.
Organic compound
An organic compound is any member of a large class of gaseous, liquid, or solid chemical compounds whose molecules contain carbon. For historical reasons discussed below, a few types of carbon-containing compounds such as carbides, carbonates, simple oxides of carbon, and cyanides, as well as the...
s with the formula C12H25C6H4SO3Na. It is a colourless salt with useful properties as a surfactant
Surfactant
Surfactants are compounds that lower the surface tension of a liquid, the interfacial tension between two liquids, or that between a liquid and a solid...
. It is usually produced as a mixture of related sulfonates. It is a major component of laundry detergent
Laundry detergent
Laundry detergent, or washing powder, is a substance that is a type of detergent that is added for cleaning laundry. In common usage, "detergent" refers to mixtures of chemical compounds including alkylbenzenesulfonates, which are similar to soap but are less affected by "hard water." In most...
.
Alkylbenzenesulfonates
Most sodium dodecylbenzenesulfonates are a member of the linear alkylbenzenesulfonates, meaning that the dodecylDodecane
Dodecane is a liquid alkane hydrocarbon with the chemical formula CH310CH3 , an oily liquid of the paraffin series. It has 355 isomers....
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 to the right 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 (see figure to left) but are not as widely used because they biodegrade too slowly.
Further complicating the description of the commercial materials, sodium dodecylbenzenesulfonate is but 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.
Production
Billions of kilograms are produced annually. Given the large scale of the application, the alkylbenzenesulfonates have been prepared by many methods. In the most common route, benzene is alkylated by long chain monoalkenes (e.g. dodecene) using hydrogen fluorideHydrogen fluoride
Hydrogen fluoride is a chemical compound with the formula HF. This colorless gas is the principal industrial source of fluorine, often in the aqueous form as hydrofluoric acid, and thus is the precursor to many important compounds including pharmaceuticals and polymers . HF is widely used in the...
as a catalyst. The purified dodecylbenzene
Dodecylbenzene
Dodecylbenzene is an organic compound with the formula C12H25C6H5. This colourless waxy solid consists of a dodecyl group attached to a phenyl group...
s (and related derivatives) are then sulfonated with sulfur trioxide
Sulfur trioxide
Sulfur trioxide is the chemical compound with the formula SO3. In the gaseous form, this species is a significant pollutant, being the primary agent in acid rain. It is prepared on massive scales as a precursor to sulfuric acid.-Structure and bonding:Gaseous SO3 is a trigonal planar molecule of...
to give the sulfonic acid
Sulfonic acid
Sulfonic acid usually refers to a member of the class of organosulfur compounds with the general formula RS2–OH, where R is an alkyl or aryl. The formal part of acid, HS2–OH, are formally derivatives of the "parent" inorganic compound with the formula HSO2.-Preparation:Sulfonic acid is...
. The sulfonic acid is subsequently neutralized with sodium hydroxide.