Sulfonates alkylbenzenesulfonates

See TEA alkylbenzene sulfonate Alkylbenzenesulfonic acid. See Dodecylbenzenesulfonic acid Alkylbenzol CIO-13 distillation residues. See Benzene, mono-CI0-13-alkyl derive., distillation residues... 

Detergents are metal salts of organic acids used primarily in crankcase lubricants. Alkylbenzenesulfonic acids, alkylphenols, sulfur- and methjiene-coupled alkyl phenols, carboxyUc acids, and alkylphosphonic acids are commonly used as their calcium, sodium, and magnesium salts. Calcium sulfonates, overbased with excess calcium hydroxide or calcium carbonate to neutralize acidic combustion and oxidation products, constitute 65% of the total detergent market. These are followed by calcium phenates at 31% (22). 

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. 

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... 

Sulfur dioxide is usefiil as a solvent for sulfur trioxide in sulfonation reactions for example, in the large-scale production of alkylbenzenesulfonate surfactant (329). A newer use for sulfur dioxide is in cyanide detoxification in connection with cyanide leaching of precious metals from mine dumps. 

Chemical Designations - Synonyms Alkylbenzenesulfonic acid, sodium salt Sulfonated alkylbenzene ... 

The development of alkylbenzenesulfonates (ABSs) goes back to 1923, when the British chemist Adams discovered that it was possible to obtain water-soluble products by the sulfonation and neutralization of hexadecyl- and octadecyl-benzene. Such products have also soap-like characteristics [1]. In 1926 IG-Farbenindustrie (Hoechst) and Chemische Fabrik Pott, Pirna/Sachsen simultaneously discovered that long-chain ABSs have excellent surface-active properties. 

The color of the derivative alkylbenzenesulfonic acid is clearly better. The solubility characteristics remain good. An olefin from the Pacol-Olex process (C, 0/13 olefin) is used as a starting olefin. The DeFine step is employed to reduce the diolefin content to <0.5%. With such an olefin an LAB is obtained over an aluminum chloride catalyst with a linear content of >99% and from which the sulfonation product has a biodegradability (DOC) comparable to that of other LABs[122,123].Table 25 gives typical physical-chemical data about different LAB types. 

However, it could be expected that the share of the latter group will rise to the same extent as the rising importance of environmental digestibility. It is very possible that in the future the C16/C18 ester sulfonates will partly replace the alkylbenzenesulfonates produced from petrochemical raw material [6,7]. N. R. Smith [8] expects the a-sulfo methyl esters to be an alternative to ethylene-based surfactants. An increase in the production of surfactants based on ethylene is problematic, because in industrial countries ethylene production is occurring at 95% of capacity and more. 

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]. 

Next, the dilution product is allowed to separate into two phases and the lower, aqueous acid layer is removed as spent acid. Much of the color produced during the sulfonation is contained in the spent acid. The upper layer in the separator, which contains around 90% alkylbenzenesulfonic acid (the remainder being primarily dissolved sulfuric acid), is also removed from the separator and neutralized with sodium hydroxide solution or with sodium carbonate solution to yield the active paste. When sodium hydroxide is used a considerable amount of heat must be removed. This is done in the third loop reactor of this process, the neutralization heat exchanger (also known as the neutralizer). If sodium carbonate solution is used, the neutralization is much less exothermic and no heat exchanger is needed at this stage. 

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. 

Anhydrous sulfonic acids, particularly linear alkylbenzenesulfonic acids, are typically stored in stainless steel containers, preferably type 304 or 316 stainless steel. Use of other metals, such as mild steel, contaminates the acid with iron (qv), causing a darkening of the acid over time (27). The materials are usually viscous oils which may be stored and handled at 30—35°C for up to two months (27). All other detergent-grade sulfonic acids, eg, alcohol sulfates, alcohol ether sulfates, alpha-olefin sulfonates, and alpha-sulfomethyl esters, are not stored owing to instability. These are neutralized to the desired salt. 

Amnionic surfactants used in shampoos, cosmetics, toothpaste, and laundry products include linear alkylbenzenesulfonates (LAS), alcohol sulfates (AS), alcohol ethoxysulfates (AES), alcohol glycerol ether sulfonates, and alpha-olefin sulfates. Household end use of anionic surfactants in the United States was 7.3 X 105 metric tons in 1987 LAS, AS, and AES accounted for 98% of the total (I). 

Sulfonation is important in the commercial production of an important class of detergents —the sodium alkylbenzenesulfonates ... 

Alkyl groups for linear alkylbenzenesulfonate detergents are made through linear a-olefins. //-alkanes can be dehydrogenated to a-olefins, which then can undergo a Friedel-Crafts reaction with benzene as described above for the nonlinear olefins. Sulfonation and basification gives the linear alkylbenzenesulfonate detergent. 

Sulfonation is economically important because alkylbenzene sulfonates are widely used as detergents. Sulfonation of an alkylbenzene (R = unbranched C10-C14) gives an alkylbenzenesulfonic acid, which is neutralized with base to give an alkylbenzene sulfonate detergent. Detergents are covered in more detail in Section 25-4. 

Sulfonated aromatic compounds are released into the environment from industrial and domestic uses of detergents. Environmental microbes easily metabolize alkylbenzenesulfonates with unbranched alkyl groups, so these compounds are considered to be biodegradable. 

A relatively new process for siloxane manufacture is aqueous phase emulsion polymerization. Cyclosiloxanes such as D4 when mixed with water and alkylbenzenesulfonates as a surfactant, along with some free sulfonic acid, form an emulsion. When the mixture is heated to > 60 °C, ring opening of the cyclosiloxane takes place to give a, ty-dihydroxy oligosiloxanes, which undergo acid-catalyzed condensation to form long-chain siloxanes. 

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