Sodium lauryl sulfate, production

Alcohol sulfates commonly have free alcohol and electrolytes as impurities. Other hydrophobic impurities can also be present. A method suitable for the purification of surfactants has been proposed by Rosen [120]. Consequently, commercial products have CMCs that deviate from the accepted reference values. This was demonstrated by Vijayendran [121] who studied several commercial sodium lauryl sulfates of high purity. The CMC was determined both by the conductimetric method and by the surface tension method. The values found were similar for both methods but while three samples gave CMC values of 7.9, 7.8, and 7.4 mM, close to the standard range of 8.0-8.2 mM, three other samples gave values of 4.1, 3.1, and 1.7 mM. The sample with a CMC of 7.9 mM was found to have a CMC of 8.0 mM with no detectable surface tension minima after purification and recrystallization. This procedure failed in all other cases. 

Composition of Emulsion, The prototype oil/water emulsion described in Table I contained ingredients typical of a large number of cosmetic products, although simplified somewhat to avoid analytical problems. The aqueous phase contained sodium lauryl sulfate (SLS) as emulsifier, 0,2% (19 n ) DEA as precursor to NDEIA and 0,1% benzoic acid as preservative. 

Although the pure drug form of compounds such as these may dissolve more slowly than their true Class I counterparts, it is relatively easy to formulate products from which they can dissolve quickly at pH values typical of the small intestine by using standard formulation techniques such as micronization or addition of small amounts of surfactants (sodium lauryl sulfate is a popular choice) to the formulation. 

Alcohol sulfates (AS) are usually manufactured by the reaction of a primary alcohol with sulfur trioxide or chlorosulfonic acid followed by neutralization with a base. These are high foam surfactants but they are sensitive to water hardness and higher levels of phosphates are required. This latter requirement has harmed the market for this type of detergent, but they are 2% of production for the major household surfactant market. Sodium lauryl sulfate (R = Cn) is a constituent of shampoos to take advantage of its high-foaming properties. 

Sodium lauryl sulfate/benzene Rhodopseudomonas sphaeroides Hydrogen production by cells entrapped in RMs was 25-fold higher [282]... 

Numerous dienes and polyenes have been subjected to hydroxymercuration-demercuration.311 With nonconjugated dienes, the products can usually be predicted by applying what one has learned from the corresponding simple alkenes. Isolated double bonds are more reactive than conjugated double bonds and frequently one of the double bonds is sufficiently more reactive than the others that monohydroxy-lated products can be obtained. Improvements in selectivity have been reported by using mercury(II) tri-fluoroacetate339 or by adding sodium lauryl sulfate.340... 

The industrial Wacker process is carried out in aqueous hydrochloric acid using PdClj/CuCh as the catalyst under oxygen pressure. The oxidation of higher terminal alkenes under the same conditions is slow and sometimes accompanied by undesired by-products formed by the chlorination of carbonyl com-poimds by CuCh, and isomerization of double bonds. Earlier examples of oxidation of various alkenes, mainly in aqueous solutions, have been tabulated.The pseudo-first-order rate constants for oxidation of various alkenes, relative to the value for cycloheptene, with PdCb in the presence of benzoquinone in aqueous solution have been rqwrted. An accelerating effect of surfactants such as sodium lauryl sulfate on the stoichiometric oxidation of higher alkenes in an aqueous solution has been reported. 

Mouran et al. [105] polymerized miniemulsions of methyl methacrylate with sodium lauryl sulfate as the surfactant and dodecyl mercaptan (DDM) as the costabilizer. The emulsions were of a droplet size range common to miniemulsions and exhibited long-term stability (of greater than three months). Results indicate that DDM retards Ostwald ripening and allows the production of stable miniemulsions. When these emulsions were initiated, particle formation occurred predominantly via monomer droplet nucleation. The rate of polymerization, monomer droplet size, polymer particle size, molecular weight of the polymer, and the effect of initiator concentration on the number of particles all varied systematically in ways that indicated predominant droplet nucleation. 

The active portion of this class of emulsifiers is the anion. In general, these emulsifiers are more acid-stable and permit adjustment of the emulsion pH level to the desirable range of 4.5 and 6.5. Common examples include sodium lauryl sulfate and soaps such as triethanolamine stearate. Triethanolamine stearate is one of the most popular emulsifiers for creams and lotions in use today. It is usually prepared in situ during manufacture from stearic acid in the hot oil phase and from triethanolamine in the hot aqueous phase. The amount of triethanolamine controls the pH level of the resulting product. 

Aquacoat ECD and Surelease are two commercially available ethylcellulose pseudolatex dispersions. Aquacoat ECD. a product of FMC Corporation, is produced by an emulsification/solvent evaporation proce.ss that utilizes sodium lauryl sulfate and cetyl alcohol as colloid. stabilizers (64). The Aquacoat ECD dispersion contains approximately 27% ethylcellulose and 30% total solids. The dispersion does not contain plasticizer, and therefore an appropriate plasticizer must be added to the dispersion prior to coating. The dispersion is typically diluted to a final solids content in the range of 15-20% prior to spray coating. Although, intended to be a pH-independent sustained release coating system, the content of sodium lauryl sulfate in the Aquacoat ECD dispersion has been demonstrated to cause reduced drug release rates in acidic media versus media of neutral pH (65.66). 

These products include household and industrial cleaners, cosmetics, and hair treatments. Surfactants contribute to adverse dermal reactions by stripping the oils that protect the skin, leaving the skin more vulnerable to attack by other chemical species. For example, it was found in one study that the simultaneous application of known contact allergens and a surfactant, sodium lauryl sulfate, to the skin results in an enhanced response to the allergens. ... 

The products discussed above touch us in every moment of our lives. We wake in the morning to an alarm clock in a polystyrene case we arise from our polyester blend sheets and slip on a pair of slippers glued with polyurethane glue. We flip the polymethylmethacrylate light switch and walk across a Nylon carpet to the bathroom. Our polymethylmethacrylate toothbrush is sitting on the Formica counter top. It has Nylon bristles. The soap we use to wash our face may be hydrocarbon derived sodium lauryl sulfate. We walk to the kitchen with polyvinyl chloride floors and sit at a Formica table. The polyethylene milk carton is at hand to supply the milk for the cereal stored in the polyethylene bag. It is eaten from a urea formamide bowl. The frying pan has a phenolformaldehyde plastic handle and a Teflon interior coating. 

In most practical applications, mixtures of surfactants, rather than individual surfactants, are used. In some cases, this is involuntary, since the commercial surfactants used, even when designated by the name of an individual surfactant, e.g., sodium lauryl sulfate, are mixtures of surface-active materials as a result of the nonhomogeneous raw materials used in their manufacture and/or the presence of unreacted raw materials and manufactured by-products. In other cases, different types of surfactants are purposely mixed to improve the properties of the final product. 

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