Sodium fatty alcohol sulphates, sodium dodecyl sulfate (SDS or
NaDS), or sodium lauryl sulfate (SLS) is an organic compound with the formula
CH3(CH2)11OSO3Na. It is an anionic
surfactant used in many cleaning and hygiene products. The salt is of an
organosulfate consisting of a 12-carbon tail attached to a sulfate group,
giving the material the amphiphilic properties required of a detergent. Being
derived from inexpensive coconut and palm oils, it is a common component of
many domestic cleaning products.
SLS is synthesized by treating lauryl alcohol with sulfur
trioxide gas, oleum, or chlorosulfuric acid to produce hydrogen lauryl sulfate.
The industrially practiced method typically uses sulfur trioxide gas. The
resulting product is then neutralized through the addition of sodium hydroxide
or sodium carbonate. Lauryl alcohol is in turn usually derived from either
coconut or palm kernel oil by hydrolysis, which liberates their fatty acids,
followed by hydrogenation.
Due to this synthesis method, commercial samples of SLS are
often a mixture of other alkyl sulfates, dodecyl sulfate being the main
component. SLS is available commercially in powder and pellet forms. It seems
the pellet form dissolves faster than the powder form in water.
SLS is mainly used in detergents for laundry with many cleaning
applications. SLS is a highly effective surfactant and is used in any task
requiring the removal of oily stains and residues. For example, it is found in
higher concentrations with industrial products including engine degreasers,
floor cleaners, and car wash soaps. It is found in toothpastes, shampoos,
shaving foams, and bubble bath formulations in part for its thickening effect
and its ability to create a lather.
Some species of insects
are attracted to sodium lauryl sulfate or anionic surfactant, even in small
amounts, and are then killed by it. It is the main active ingredient in many house
fly killers. . Sodium lauryl sulfate is commonly used in preparing proteins for
electrophoresis. It is used in the analysis of hemoglobin.