Alcohols sulfate surfactants from

A specific example, using model surfactant structures, was studied in the P G laboratories. Snoody found that the Krafft boundary could be altered dramatically by addition of a small methyl substituent on the chain of a methyl-substituted octadecylsulfate. P G has published some work on mixtures of midchain methyl-substituted alcohol sulfate surfactants. The resulting increased solubility of these alcohol sulfates called highly soluble alcohol sulfates (HSAS) allows use of long-chain alcohols, such as in laundry detergents under today s cold and hard water environments. The solubility effect is maximized when the methyl substitution is away from the end of the surfactant chain as shown in Figure 6.13. 

The majority of the world s oleochemical-derived alcohol sulfates comes from four main sources today—coconut, pahn, palm kernel, and tallow. The majority of surfactant alcohol volume comes from coconut and palm kernel oil due to the high content of C 2- a ft " fatty-alcohol production as discussed earlier. However, several new initiatives are now underway to broaden the available existing sources of plant oils. 

Discussion The elimination of interferences is aimed at making the methylene blue method more nearly specific for the chief surfactant component of municipal wastewater LAS. The acid hydrolysis destroys alcohol sulfate surfactants, for example, which in a specific application may or may not be considered an interference to be eliminated. Acid hydrolysis also aids the recovery of LAS adsorbed onto solids. The main contribution of the anion exchange step is the elimination of cationic materials which would complex with LAS to give low results. The XAD-2 concentration step effectively removes inorganic materials from the system. 

The adsorbed layer at G—L or S—L surfaces ia practical surfactant systems may have a complex composition. The adsorbed molecules or ions may be close-packed forming almost a condensed film with solvent molecules virtually excluded from the surface, or widely spaced and behave somewhat like a two-dimensional gas. The adsorbed film may be multilayer rather than monolayer. Counterions are sometimes present with the surfactant ia the adsorbed layer. Mixed moaolayers are known that iavolve molecular complexes, eg, oae-to-oae complexes of fatty alcohol sulfates with fatty alcohols (10), as well as complexes betweea fatty acids and fatty acid soaps (11). Competitive or preferential adsorption between multiple solutes at G—L and L—L iaterfaces is an important effect ia foaming, foam stabiLizatioa, and defoaming (see Defoamers). 

Higher molecular primary unbranched or low-branched alcohols are used not only for the synthesis of nonionic but also of anionic surfactants, like fatty alcohol sulfates or ether sulfates. These alcohols are produced by catalytic high-pressure hydrogenation of the methyl esters of fatty acids, obtained by a transesterification reaction of fats or fatty oils with methanol or by different procedures, like hydroformylation or the Alfol process, starting from petroleum chemical raw materials. 

In 1932 the first household detergent based on synthetic surfactants was brought into the market under the name FEWA (Feinwaschmittel). The product was produced from fatty alcohol sulfate by Bohme Fettchemie in Chemnitz. The shortage of the necessary natural raw materials caused by World War II led to the development of products based on more readily available raw materials [2],... 

Alcohol sulfates were first obtained either by the reaction of olefins with sulfuric acid or by sulfation of alcohols produced by hydrogenolysis of oils and fats with sulfuric acid. With the advent of petrochemistry and the progress of chemistry and chemical engineering, alcohol sulfates and their derivatives have become one of the most important surfactants and are produced in large amounts using techniques different from those originally used. They are based on a wide range of alcohols and have found applications in almost all domestic and industrial sectors. 

As esters of sulfuric acid, the hydrophilic group of alcohol sulfates and alcohol ether sulfates is the sulfate ion, which is linked to the hydrophobic tail through a C-O-S bond. This bond gives the molecule a relative instability as this linkage is prone to hydrolysis in acidic media. This establishes a basic difference from other key anionic surfactants such as alkyl and alkylbenzene-sulfonates, which have a C-S bond, completely stable in all normal conditions of use. The chemical structure of these sulfate molecules partially limits their conditions of use and their application areas but nevertheless they are found undoubtedly in the widest range of application types among anionic surfactants. 

The reaction of olefin sulfation and its possibilities has been extensively studied [3-10] and it was used to produce alcohol sulfates. Dry distillation of spermaceti gives palmitic acid and cetene-1, which can be sulfated with sulfuric acid to give cetyl-2 sulfate [11]. Other surfactants were obtained from olefins produced from natural substances, such as alcohol sulfates by sulfation of olefins from decarboxylation of oleic acid [12], by sulfation of olefins made by dehydrating hydroabietyl alcohol, by direct sulfation of abietyl alcohol [13,14], or by sulfation of natural terpenes [15]. 

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. 

Multilamellar liposomes, absorbed on paper, containing extrapped peroxidase permit the quantitative determination of alcohol sulfates by measuring the amount of peroxidase released from the liposomes as this amount varies with the amount of surfactant [272]. 

Compared with the fatty alcohol sulfates, which are also oleochemically produced anionic surfactants, the ester sulfonates have the advantage that their raw materials are on a low and therefore cost-effective level of fat refinement. The ester sulfonates are produced directly from the fatty acid esters by sulfona-tion, whereas the fatty alcohols, which are the source materials of the fatty alcohol sulfates, have to be formed by the catalytic high-pressure hydrogenation of fatty acids esters [9]. The fatty acid esters are obtained directly from the fats and oils by transesterification of the triglycerides with alcohols [10]. 

The shift to oleochemicals has been supported by increasing environmental concerns and a preference by some consumers, especially in Europe, for materials based on natural or renewable resources. Although linear alkylbenzenesulfonates (LASs) are petrochemically based, alcohol ethoxylates, alcohol ethoxysulfates, and primary alcohol sulfates are derived from long-chain alcohols that can be either petrochemically or oleochemically sourced. There has been debate over the relative advantages of natural (oleochemical) vs synthetic (petrochemical) based surfactants. However, detailed analyses have shown there is litde objective benefit for one over the other. 

Industrial surfactants find uses in almost every industry, from asphalt manufacturing to carpet fibers, from pulp and paper production to leather processing. Examples of the types of chemicals used as surfactants are fatty alcohol sulfates, alkanolamides, alkoxylates, sulfosuccinates, amines, quaternaries, phosphate esters, acid esters, blockcopolymers, betaines, imidazolines, alkyl sulfonates, etc. 

Lauryl is the old name for a chain of twelve carbon atoms the modern name is dodecyl (do = 2, decyl = 10). The commonly used surfactant sodium lauryl sulfate is made from lauryl alcohol which comes from coconut oil or palm kernel oil. 

The major subgroups of anionic surfactants include the alkali carboxylates (soaps), sulfates, sulfonates, and to a smaller degree, phosphates. The esterification of alcohol with sulfuric acid yields probably the best-studied surfactant, sodium dodecylsulfate or SDS. SDS, a sulfate ester, is an extremely effective emulsifier because of its high-electrostatic repulsion. Other sulfates are, for example, sulfated esters from fatty acids, sulfated ethers, and sulfated fats and oils. Sulfonates stem from the reaction of sulfonic acid with suitable substrates. Members of the class of sulfonates are, for example, sulfonic acid salts or aliphatic sulfonates. Other anionic surfactants include substances such as carboxylated soaps and esters of phosphoric acid. 

Coco-Based Surfactants. The most important coconut oil-based surfactants are fatty alcohol sulfate, fatty alcohol ether sulfate, and fatty alcohol polyglycol ether. Two relatively new coco-based surfactants are fatty acid methyl ester sulfonate and alkyl polyglycoside, which is produced from fatty alcohol and starch or sugar, both renewable materials. 

Vineland, NJ) or over-the-counter cosmetic creams promoted for improved hydration (L Oreal, Paris and Dior, Paris). More recently, parenteral liposome formulations of amphotericin B, doxorubicin, and dau-norubicin have been approved and marketed (ABELCET, Elan, the Liposome Co., Inc, Princeton, NJ AmBisome and DaunoXome, Nexstar/Fujisawa, Deerfield Park, IL Amphotec and Doxil, Sequus/ Alza, Menlo Park, CA), with others on the horizon for applications in photodynamic therapy. Although the vast majority of liposome preparations are constructed from phospholipids, other nonphospholipid materials can be used either alone or in mixtures to form bilayer arrays. One such example is Amphotec, which utilizes sodium cholesteryl sulfate as the primary lipid. Other liposome forming materials may include but are not limited to fatty-acid compositions, ionized fatty acids, or fatty acyl amino acids, longchain fatty alcohols plus surfactants, ionized lysophospholipids or combinations, non-ionic or ionic surfactants and amphiphiles, alkyl maltosides, a-tocopherol esters, cholesterol esters, polyoxyethylene alkyl ethers, sorbitan alkyl esters, and polymerized phospholipid compositions. ° ... 

To obtain a wide w/o microemulsion phase it is essential to adjust carefully the cosurfactant structure (usually its chain length) and its relative amount. Although trial and error is still the most commonly used method for obtaining microemulsions, a tentative rule is to combine a very hydrophobic cosurfactant (n-decanol) with a very hydrophilic ionic surfactant (alcohol sulfate) and a less hydrophobic cosurfactant (hexanol) with a less hydrophilic ionic surfactant (OTAB). For very hydrophobic ionic surfactants, such as dialkyl dimethylammonium chloride, a water-soluble cosurfactant, such as butanol or isopropanol, is adequate (this rule derives at least partially from the fact that an important feature of the cosurfactant consists of readjusting the surfactant packing at the solvent/oil interface). 

These are also anionic surfactants which are manufactured by sulfating alcohol ethoxylate surfactants [69], Figure 8.5 shows the structure of the molecule which consists of the alcohol ethoxylate connected to a sulfate group. The EO groups typically range in size from 1 to 3 moles. 

These anionic surfactants (Figure 8.5) are used primarily in Europe as a substitute for LAS [45], Environmental considerations have prompted manufacturers to use surfactants of this type, which can be derived from oleochemical sources. The carbon chain length can range from CIO to Cl8. Tallow alcohol sulfate is the... 

Many surfactants are made from petroleum with hazardous reagents. Sulfur trioxide was used with the carcinogen benzene to make the alkylbenzenesulfonates described earlier. The carcinogen ethylene oxide is used to make many nonionic surfactants from phenols and long-chain alcohols. A common surfactant, sodium dodecyl sulfate, is made from an alcohol derived from coconut oil by reduction followed by treatment with sulfur trioxide. Long-chain tertiary amines derived from natural fats and oils are quat-ernized with methyl chloride. Perhaps this can be done with... 

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