Alkylbenzene sulphonates

Global consumption of LAB is estimated at approximately 3 million tonnes per annum, making it the most commonly used anionic surfactant [ 1 ]. Its popularity can be attributed to its relative ease of manufacture, ability to be easily stored, transported and handled in a highly concentrated form (the 96% active sulphonic acid) and its efficiency as a detergent. Due to this near-universal application, it is also probably the most researched and documented, especially in terms of its fate in the environment. 

Raw materials. LAB is made by Friedel-Kraft alkylation of benzene with an n-alkene. The choice of catalyst and the composition of the alkene have a very significant effect on the performance of the surfactant, especially on its physical characteristics and that of the overall formulation. 

Due to their high molecular weights, these compounds are easily removed by distillation. There is a market for the dialkylbenzenes which can be sulphonated to produce synthetic petroleum sulphonates. 

The chloroparaffin/AlCl3 route is the longest established, but now represents only a minority (-10%) of LAB supply. The product is H2P, with 2-phenyl isomer levels of28-30%. The reaction can be more difficult to control and yields not only a high level of dialkyl tetralin (DAT) impurities, but also high levels of dialkylbenzene and diphenylalkanes. The spent catalyst has to be removed by filtration. 

The cloud point of the high 2-phenyl product remains below 0°C up to 25% LAS whereas the low 2-phenyl cloud point is 15°C. In practice, this means that a formulation based on L2P surfactant would need higher additions of solvent or hydrotrope to keep the solution clear and stable at lower temperatures. 

Source Reproduced by permission from Elsevier Science, UK [5] 

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Benzene (and alkylbenzene) sulphonic acids QH5SO3H Detergents, phenols, dyes... 

Boeije GM, Schowanek DR, Vanrilleghem A (2000) Incorporation of biofilm activity in river biodegradation modeling a case study for linear alkylbenzene sulphonate (LAS). Wat Res 34 1479... 

Linear Alkylbenzene Sulphonates (LAS) and Alkylphenol Ethoxylates (APE) in Waters, Wastewaters and Sludges by High... 

Brunner PH, Capri S, Marcomini A, Giger W (1988) Occurrence and behaviour of linear alkylbenzene sulphonate, nonylphenol, nonylphenol mono- and nonylphenol diethoxylates in sewage and sewage sludge treatment. Water Res 22 1465-1472... 

Navas JM, Gonzalez-Mazo E, Wenzel A, Gomez-Parra A, Segner H (1999) Linear alkylbenzene sulphonates and intermediate products from their degradation are not estrogenic. Mar Pollut Bull 38 880-884... 

Both urban and industrial wastewater often contains high concentrations of surfactants. Cationic (like alkylbenzene sulphonates) and non-ionic surfactants (like alcohol ethoxylates) are among the most-used surfactants and are discharged into sewers in widely varying concentrations. Two on-line methods have been designed for the monitoring of cationic surfactants with UV spectrophotometry [46] and non-ionic surfactants by on-line titration [47]. The detection limits are around 10 mg L. ... 

HMSO (1993) Linear alkylbenzene sulphonates and alkylphenolethoxylates in waters, waste waters and sludges by high-performance liquid chromatography, HMSO, London. 

Surfactants elimination via bile is faster in fed than in unfed fish [12,40], due to the higher secretion of bile into the digestive tract when fed. The fastest and slowest surfactants excreted were the linear alkylbenzene sulphonates (C12) and the alkyl sulphates (especially the C12-15) [12], respectively. Depuration of NP is quite rapid, 1.8-20 days in fathead minnows [32] and 4 days in the Atlantic salmon [41]. Within the same organism, differences in tissues were observed, with values of 20 h for adipose tissue and 18.5 h for muscle of rainbow trout [24]. The elimination rate of non-ionic surfactants is directly proportional to the ethoxylate unit number and inversely proportional to the alkyl chain length [33]. Average elimination rates (k2) of NPE02.8 and NP in clams were 1.8 and 1.4 per day, respectively [21], and decreasing k2 values from 0.19 to 0.001 per day were obtained from butylphenol to dodecylphenol in salmon [42]. 

J. Solbe, Linear alkylbenzene sulphonates (LAS) risk assessment for sludge-amended soils, SPT Workshop, Copenhagen, April 19-20 1999. 

Low cost Choose from the following most widely used ones soaps, linear alkylbenzene sulphonates (LABS), alcohol ethoxysulphates (AES), alcohol sulphates (AS), alkane or paraffin sulphonate (SAS), and alcohol ethoxylates (AE)... 

Marchesi J.R., W.A. House, G.F. White, N.J. Russell, and I.S. Earr (1991). A comparative study of the adsorption of linear alkyl sulphates and alkylbenzene sulphonates on river sediments. Colloids and Surfaces 53 63-78. 

Cavalli, L., G. Cassani, M. Lazzarin, C. Maraschin, G. Nucd, and L. Valturta. 1996. Iso-branching of linear alkylbenzene sulphonate (LAS). Tenside Surf. Det. 33, 393-398. 

Verge, C., Moreno, A., Bravo, J. and Bema, J.L. (2001) Influence of water hardness on the bioavailability and toxicity of linear alkylbenzene sulphonate (LAS), Chemosphere 44 (8), 1749-1757. 

Applications of this technique are growing and include the analysis of mixtures of pesticides and herbicides, including oiganophosphorus, phenoxyacetic acid, caibamate, urea types, mixtures of various types of organic compounds, alkylbenzene sulphonates, polyethylene glycols, nonylphenyl ethoxylates, dioctadecylmethyl ammonium, ozonisation products and chlorination products. 

Carbonyl compounds, -halogenated anilines, benzidines, nitro compounds, phenols, polychlorinated compounds, alkylbenzene, sulphonates, alkyl sulphonates, alkylbenzene sulphonates, carbamates [155]... 

Taylor and Nickless [1] have described a paired-ion high performance liquid chromatographic technique for the separation of mixtures of linear alkylbenzene sulphonates and p-sulphophenylcarboxylate salts,... 

Fig. 7.1 shows the trace obtained from the analysis of undegraded linear alkylbenzene sulphonate (LAS) mixture (sodium dodecylbenzene sulphonate). Peak identifications were made by co-injection with pure undegraded linear alkylbenzene sulphonate compounds and confirmed by analysis of the undegraded linear alkylbenzene sulphonate mixture by desulphonation followed by gas chromatography of the resultant alkylbenzenes on a 15m OV-1 support coated open-tubular column. 

Linear alkylbenzene sulphonates (C9-C15 homologues) LAS as 1 methylheptyl amine extracted into hexane Micro sulphonation-GLC technique lOpgL-1 [347]... 

Linear alkylbenzene, sulphonates, dialky ltetraline sulphonates, and biodegradation intermediates Electron capture Derivativisation then electron capture GC-MS [194]... 

Foaming of urea - formaldehyde resins for cavity wall insulation Alkylbenzene sulphonic acids and salts Foaming agents... 

Polyglycol ethers Alkanolamides Alkyl ether sulphates Alkylbenzene sulphonates (amine salts) Alkylphenol ethoxylates Alkanolamides Alkylbenzene sulphonates (amine salts)... 

Hydrophobic tail Alkylbenzene sulphonate Phosphatidyl choline (phospholipids) Alkyl secondary amines... 

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