Alkylbenzenesulfonates linear

Alkylation. Benzene and phenol feedstocks are readily alkylated under Friedel-Crafts conditions to prepare extensive families of alkylated aromatics. These materials generally are intermediates in the production of surfactants or detergents such as linear alkylbenzenesulfonate (LABS) and alkylphenolethoxylate (APE). Other uses include the production of antioxidants, plasticizers, and lube additives. 

Linear alkylbenzenesulfonic acid is the largest intermediate used for surfactant production in the world. In the United States it has been determined that 2.6 g/d of material is used per inhabitant (46). Owing to the large volumes of production and consumption of linear alkylbenzenesulfonate, much attention has been paid to its biodegradation and a series of evaluations have been performed to thoroughly study its behavior in the environment (47—56). Much less attention has been paid to the environmental impact of other sulfonic acid-based materials. 

Linear alkylbenzenesulfonate showed no deleterious effect on agricultural crops exposed to this material (54,55). Kinetics of biodegradation have been studied in both wastewater treatment systems and natural degradation systems (48,57,58). Studies have concluded that linear alkylbenzenesulfonate does not pose a risk to the environment (50). Linear alkylbenzenesulfonate has a half-life of approximately one day in sewage sludge and natural water sources and a half-life of one to three weeks in soils. Aquatic environmental safety assessment has also shown that the material does not pose a hazard to the aquatic environment (56). 

Surfactants and Detergents Uses. Perhaps the largest use of sulfonic acids is the manufacture of surfactants (qv) and surfactant formulations. This is primarily owing to the dominance of linear alkylbenzenesulfonic acid production for detergent manufacture. In almost all cases, the parent sulfonic acid is an intermediate which is converted to a sulfonate prior to use. The largest volume uses for sulfonic acid intermediates are the... 

AH detergent proteases are destabilized by linear alkylbenzenesulfonate (LAS), the most common type of anionic surfactant in detergents. The higher the LAS concentration and wash temperature, the greater the inactivation of the enzyme. The presence of nonionic surfactants, however, counteracts the negative effect of LAS. Almost aH detergents contain some nonionic surfactant therefore, the stabHity of proteases in a washing context is not problematic. 

Laundry and cleaning products (powder and liquid household cleaners), in which linear alkylbenzenesulfonate (LAS) and tetrapropylenebenzenesulfonate (TPBS) are used in combination with other surfactants, builders, and additives. Today TPBS is used only in small amounts because of its poor biodegradability. 

TABLE 21 Biodegradation Data from Linear Alkylbenzenesulfonate (C1 6-LAS)... 

Physical Properties and Behavior of Linear Alkylbenzenesulfonates in Mixtures with Other Surfactants in Household Detergent Products... 

Examples comparing the secondary alkanesulfonate content of influents and effluents of various sewage treatment plants with the concentrations of linear alkylbenzenesulfonates are shown in Table 12. In sludges the specimen secondary alkanesulfonate (linear alkylbenzenesulfonate) concentration of less than 0.1... 

TABLE 12 Secondary Alkanesulfonates (SAS) and Linear Alkylbenzenesulfonates (LAS) in Sewage Treatment Plant Influents and Effluents (pg/L)... 

APG, alkyl polyglucoside FAA, fatty acid alkanolamide FAEO, fatty alcohol ethoxylate FAES, fatty alcohol ether sulfate FAGA, fatty acid glucamide FAS, fatty alcohol sulfate LAS, linear alkylbenzenesulfonate SAS, secondary alkanesulfonate. 

FIG. 2 CMC of linear alkylbenzenesulfonate-a-olefmsulfonate (LABS-AOS) mixed surfactant system. (From Ref. 3.)... 

The main performance characteristics of light-duty liquids or dishwash blends are soil emulsification and foaming. Figueroa-Raulli [73] published a comparative study of AOS vs. alkyl sulfates (AS), alcohol ether sulfates (AES), and linear alkylbenzenesulfonates (LAS) in light-duty liquid blends. The blends were evaluated for flash foam, the stability of foam under accumulating soil loads, and for the number of plates washed. Blend performance is expressed as a percentage of a dishwash reference standard. 

For long-chain alcohol esters it is interesting to see that the interfacial tension between a 0.01 wt % aqueous solution and octane or xylene has a minimum for ester sulfonates with a total 22 carbon atoms in the fatty acid chain and the ester chain [60]. The balance in length between the two chains has only a poor effect. Thus, a-sulfonated fatty acid esters with a total number of 22-26 carbon atoms in the molecule have excellent interfacial activities. To attain the same magnitude in the interfacial tension between linear alkylbenzenesulfonate (LAS) solution and octane, the required concentration of LAS is 0.1 wt %. This is 10 times the concentration needed for a-sulfonated fatty acid esters [60]. 

Di Corcia, A., Marchetti, M., Samperi, R., and Marcomini, A., Liquid chromatographic determination of linear alkylbenzenesulfonates in aqueous environmental samples, Anal. Chem., 63, 1179, 1991. 

Prior, S. and B. Riemann. 1998. Effects of tributyltin, linear alkylbenzenesulfonates, and nutrients (nitrogen and phosphorus) on nucleoid-containing bacteria. Environ. Toxicol. Chem. 17 1473-1480. 

Fig. 6 General structures of the most important surfactants and metabolites alkylphenol polyethoxylate (APE) alkylphenol (AP) alkyl ether (AE) alkylphenol ethoxy carboxylate (APEC) linear alkylbenzenesulfonates (LAS) alkyltrimethylammonium compounds (ATMAC) dialkyldimethylammonium compounds (DADMAC) alkyldimethylbenzylammonium compounds (ADMBAC) esterquat (EQ) diesterquats (DEQ). X is usually a chlorine or bromine atom. DDAC (didecyldimethylammonium chloride) and BDD12AC (benzyldimethyldode-cylammonium) are the two target analytes with a reported immunochemical technique developed for their analysis [153,154]...

Thus -alkanes (C10-C14) separated from the kerosene fraction of petroleum (by urea complexation or absorption with molecular sieves) are now used as one source of the alkyl group. Chlorination takes place anywhere along the chain at any secondary carbon. Friedel-Crafts alkylation followed by sulfonation and caustic treatment gives a more linear alkylbenzenesulfonate (LAS) which is soft or biodegradable. The chlorination process is now the source of about 40% of the alkyl group used for the manufacture of LAS detergent. 

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