Wetting agents are chemical substances that can reduce the surface tension of water. Cohesive
forces between molecules cause the surface of a liquid to contract to the smallest possible
surface area. Attractive forces between molecules of the same type are called cohesive forces.
Attractive forces between molecules of different types are called adhesive forces. When surface
tension is lowered, means weakening the cohesive properties of the liquid and strengthening
adhesive properties of the liquid.
Surface Tension of water γ(N/m)
Water at 20ºC
0.0728
N/m
Alkyl aryl sulfonates had been introduced to the market for the first time in the 1930’s and
shortly after in 1945 they had become the main industrial surfactant component. The process
for producing this surfactant involves a reaction between benzene and propylene tetramer
which forms alkyl aryl. Following this, the sulfonation of alkyl aryl creates alkyl aryl
sulfonates. The biggest downside of these surfactants is their non- biodegradability. The
longer chain members of this family with C14 – C30. The surfactants used in this research
were made from oligomers of propylene. The advantage of alkyl aryl sulfonate surfactants is
their availablity of the raw material at low cost in the market.
Until the mid 1960, this largest of synthetic surfactant class was most prominently represented
by tetrapropylenebenzenesulfonate (TPS). It was found that branched chain present in TPS
prevents the compound from undergoing efficient biodegradation. Thus, means were
developed to replace it by more biodegradable linear alkylbenzene sulfonate.
Chemical Formula
Chemical Name
CAS Number
C12H25C6H4SO3Na
Sodium dodecyl benzene sulfonate,sdbs
25155-30-0
Structure
Molecular weight
Viscosity at 25°C (Pa•sec)
pH
Apparent Density
Surface tension of 0.1% of active material (N/m)
Ionic nature
Appearance of solution at 20°C
Foam height of 0.1 % active material solution
348 g/mol
0.0045
7-10.5
0.18 g/cc
0.03
Anionic
Clear liquid
Initial (cm) : 18
Final [after 5 min] (cm) :17
225
Ultraviolet absorption λmax (µm)
Primary biodegradation OECD confirmatory test 90-95
% MBAS/BiAS/DAS removal
Alkyl aryl sulfonates are used in different fields because of their effective performance. Apart
from its effective performance it has very interesting foaming characteristics. The main purpose
of this ingredient is dishwashing liquid or all purpose cleansers. which are of great significance
to its use in detergents.It is employed in formulations for liquid detergents because of its high
solubility.They are also used for treating pigments, finishing paper and in making of water
colors, as additives for cement, as well as wetting and spreading insecticides and herbicides
and to improve their penetration. They can also be used in mixtures with sodium bisulfate or
with alkaline builders in compounding industrial cleaning agents.In the paper industry for
making ground wood for mechanical pulp, separation of fibres, bleaching and rinsing.