Page 5 - 81Sulfonation-Sulfation Processing Technology for Anionic Surfactant Manufacture_opt

272 Advances in Chemical Engineering

Fig. 4. Reaction scheme of ethoxylated alcohol sulfation (adapted from de Groot, 1991)

LES (C 12-C 14/15 2-3 ethylene oxide) can be considered as the most efficient anionic surfactant
in terms of: superior detergency power, good tolerance for water hardness, and mildness on
hands and fibers. The application therefore is wide: from household to personal care and
cosmetic product. Unfortunately, sulfated alcohol ether sulfates show a limited stability to
hydrolysis at high temperatures, and this restricts their use in heavy duty laundry powders,
where high temperatures occur in the spray drying process of powder manufacture.
The high stability to calcium ions permits formulation of liquid detergents with limited or
no addition of water “softeners” even in case of use in hard water (Matthijs et al., 1999). The
optimum compromise of ethylene oxide addition to keep adequate foam levels and
solubility/mildness ratio vary from 2 to 3 moles per mole of fatty alcohol. The most
important worldwide application of AES 2-3 ethylene oxide (EO) are in dish washing liquid
detergent, generally combined with LABS and in shampoos/bubble baths (Table 2).

Liquids dish wash Shampoos/bubble
detergent baths
LES (C 12-C 14/15 2-3 EO) 5 – 10 % 10 – 30 %
LABS (low molecular weight) 15- 20%
Coconut Ethanol Amides (CEA) 2 – 3 % 2 – 3 %
Hydrotopes (Sodium Tolunene Sulfonate – 1 – 3 %
Sodium Xylene Sulfonate) alcohol solvent
Other actives (i.e. amphoteric/nonionic) 5 – 10 %
H 2O, perfume, color, preservatives Balance Balance
Table 2. Applications worldwide of AES 2-3EO combined with LABS and in
shampoos/bubble baths (de Groot, 1991)

2.4 Alfa-olefins sulfonates (AOS)
Alfa-olefins are a potential replacement for alkylbenzenes in detergent applications. Olefin
sulfonation is highly exothermic with ∆H = -210 kJ/mol (Roberts, 2001). The neutralized
product of alfa-olefin sulfonation requires hydrolysis to remove the sultones, which are
skin sensitizers (Figure 5). Their exploitation, however, is largely limited to the Far
East, Centre on Japan, at present. Commercial supplies of alfa-olefins are produced by the

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