Fatty alcohol surfactants

Both high bulk and surface shear viscosity delay film thinning and stretching deformations that precede bubble bursting. The development of ordered stmctures in the surface region can also have a stabilizing effect. Liquid crystalline phases in foam films enhance stabiUty (18). In water-surfactant-fatty alcohol systems the alcohol components may serve as a foam stabilizer or a foam breaker depending on concentration (18). 

In polymer applications derivatives of oils and fats, such as epoxides, polyols and dimerizations products based on unsaturated fatty acids, are used as plastic additives or components for composites or polymers like polyamides and polyurethanes. In the lubricant sector oleochemically-based fatty acid esters have proved to be powerful alternatives to conventional mineral oil products. For home and personal care applications a wide range of products, such as surfactants, emulsifiers, emollients and waxes, based on vegetable oil derivatives has provided extraordinary performance benefits to the end-customer. Selected products, such as the anionic surfactant fatty alcohol sulfate have been investigated thoroughly with regard to their environmental impact compared with petrochemical based products by life-cycle analysis. Other product examples include carbohydrate-based surfactants as well as oleochemical based emulsifiers, waxes and emollients. 

For styrene nanoemulsions prepared with 10 2 M sodium lauryl sulfate and a 1 1 molar ratio of ionic surfactant fatty alcohol, the order of decreasing stability with fatty alcohols of different chain length is Ci6 > Qg > CM > Ci2 > C10. For sodium lauryl sulfate-Ci6 alcohol mixtures, the order of decreasing stability with different sodium lauryl sulfate fatty alcohol ratios is 1 3 > 1 2 > 1 1 > 1 6 > 1 0.5. The 1 3 and 1 2 ratios produce emulsions with stabilities > 1 month. The presence of rodlike liquid-crystalline structures at 1 1 to 1 3 ionic surfactant fatty alcohol ratios is believed to be essential for the preparation of a stable nanoemulsion. (El-Aaser, 1984). 

The development of cosmetic microemulsion cleansers with alkyl polyglycosides (APG) was described by Forster et al. [4]. This class of non-ionic surfactants has excellent environmental and skin compatibility. Cosmetic cleanser multicomponent systems are required to have good foaming and cleansing performance. Figure 8.3 shows a pseudo-ternary phase diagram of a five-component formulation. It consists of water, the oil dioctyl cyclohexane (DOCH), the non-ionic surfactant C12/14-APG, the anionic surfactant fatty alcohol ether sulphate (FAES) and the co-surfactant sorbitan monolaurate (SML). The phase diagram... 

Sulphated anionic surfactants (fatty alcohol sulphates, alcohol ethoxysulphates)... 

Nonionic surfactants Fatty alcohol, glycerol esters, fatty acid esters... 

Jatropha curcus is another plant being developed today for its oil-bearing fruit. Biodiesel and fuel oil are key reasons for its development today. Both India and Africa are pursuing this crop as it can grow on sparse soil and in dry climates. Jatropha, shown in Figure 6.18, from a surfactant fatty alcohol feedstock is much less interesting, since it mainly contains unsaturated fatty acids with limited C 2 cid content and, thus, bears no further discussion. 

Nonionic surfactants (fatty alcohol poly(ethylene glycol) ethers, fatty acid... 

Nonionic surfactant, fatty alcohol ethoxylates (USP 5,256,329, 1,1-dichloro-1-fluoroethane Dewatering Systems),... 

Eccleston [19] reviewed the emulsion stability factors on the basis of the HLB and of the DLVO theory. He emphasized the Friberg school results which show that the presence of liquid crystals stabilizes the emulsions by delaying the film-thinning process and, consequently, by reducing the rate of coalescence. He also mentioned stabilization by the formation of a gel network (surfactant-fatty alcohol-water system). Dahms [20] explained the role of fatty alcohol as a viscosity modifier on the basis of lamella-phase generation. 

Keywords Surfactant fatty alcohol water mixture Vesicle Lamellar phase Gel NMR Pulsed field-gradient difihisometry Transmission elechtm microscopy... 

In some applications nonionic - surfactants (- fatty alcohol ethoxylates), which show the phenomenon of a cloud point, are used. Above their cloud point they act as defoamers, but below they may even act as foam stabilizers. Another special d. is silica that is made hydrophobic by treating it with - fatty amines. All these ingredients are used in solid or liquid (emulsion) form, with emulsifier to enhance dispersion. 

Many kinds of polymerizable miniemulsion recipes have been described [9,85]. In the majority of the described systems, the emulsification is achieved by high-energy methods. The emulsifier in the earlier formulations [1] consisted of ionic surfactant/fatty alcohol (cosurfactant) mixtures. It was thought that the stabilizing mechanism was due to the presence of a protective interfacial complex. Later, it was shown that the replacement of the fatty alcohol by a highly hydrophobic compound (e.g., hexadecane) decreased more effectively the Ostwald ripening without the existence of any interfacial complex [9]. Different types of molecules such as reactive co-... 

AlkylPtherSulfates. These surfactants are also found in shampoo appHcations. They are prepared similarly to alkyl sulfates except that the fatty alcohol is... 

A.lkyl Sulfosuccinate Half Asters. These detergents are prepared by reaction of maleic anhydride and a primary fatty alcohol, followed by sulfonation with sodium bisulfite. A typical member of this group is disodium lauryl sulfosucciaate [26838-05-1]. Although not known as effective foamers, these surfactants can boost foams and act as stabilizers when used ia combination with other anionic surfactants. In combination with alkyl sulfates, they are said to reduce the irritation effects of the latter (6). 

Many different types of foaming agents are used, but nonionic surfactants are the most common, eg, ethoxylated fatty alcohols, fatty acid alkanolamides, fatty amine oxides, nonylphenol ethoxylates, and octylphenol ethoxylates, to name a few (see Alkylphenols). Anionic surfactants can be used, but with caution, due to potential complexing with cationic polymers commonly used in mousses. 

Anionic surfactants are the most commonly used class of surfactant. Anionic surfactants include sulfates such as sodium alkylsulfate and the homologous ethoxylated versions and sulfonates, eg, sodium alkylglycerol ether sulfonate and sodium cocoyl isethionate. Nonionic surfactants are commonly used at low levels ( 1 2%) to reduce soap scum formation of the product, especially in hard water. These nonionic surfactants are usually ethoxylated fatty materials, such as H0CH2CH20(CH2CH20) R. These are commonly based on triglycerides or fatty alcohols. Amphoteric surfactants, such as cocamidopropyl betaine and cocoamphoacetate, are more recent surfactants in the bar soap area and are typically used at low levels (<2%) as secondary surfactants. These materials can have a dramatic impact on both the lathering and mildness of products (26). 

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). 

Nonionic Surface-Active Agents. Approximately 14% of the ethyleae oxide consumed ia the United States is used in the manufacture of nonionic surfactants. These are derived by addition of ethylene oxide to fatty alcohols, alkylphenols (qv), tall oil, alkyl mercaptans, and various polyols such as poly(propylene glycol), sorbitol, mannitol, and cellulose. They are used in household detergent formulations, industrial surfactant appHcations, in emulsion polymeri2ation, textiles, paper manufacturing and recycling, and for many other appHcations (281). 

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. 

Ethylene oxide is an important intermediate chemical not only for the production of nonionic surfactants like fatty alcohol ethoxylates, alkylphenol ethoxy lates, or propylene oxide/ethylene oxide block copolymers, but also for manufacturing of anionic surfactants like alcohol ether sulfates. 

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],... 

FIG. 36 Synergistic mixture of alkane- (paraffin) sulfonates (PS) and fatty alcohol ether sulfates (FAES). Cleaning effect in miniplate test at 50°C, tap water (12° German hardness), 0.075 g of active surfactant mixture per liter. 

There is even a method for preparing carboxymethylated surfactants with a narrow polyoxyethylene chain distribution by using as catalyst metallic Na or NaH in a molar ratio of about 1 1 to the fatty alcohol [12,13]. 

Ether carboxylates are used not only in powdered detergents but in liquid laundry detergents for their hard water stability, lime soap dispersibility, and electrolyte stability they improve the suspension stability and rheology of the electrolyte builder [130,131]. Formulations based particularly on lauryl ether carboxylate + 4.5 EO combined with fatty acid salt and other anionic surfactants are described [132], sometimes in combination with quaternary compounds as softeners [133,163]. Ether carboxylates show improved cleaning properties as suds-controlling agents in formulations with ethoxylated alkylphenol or fatty alcohol, alkyl phosphate esters or alkoxylate phosphate esters, and water-soluble builders [134]. 

The amount of residual sulfonate ester remaining after hydrolysis can be determined by a procedure proposed by Martinsson and Nilsson [129], similar to that used to determine total residual saponifiables in neutral oils. Neutrals, including alkanes, alkenes, secondary alcohols, and sultones, as well as the sulfonate esters in the AOS, are isolated by extraction from an aqueous alcoholic solution with petroleum ether. The sulfonate esters are separated from the sultones by chromatography on a silica gel column. Each eluent fraction is subjected to saponification and measured as active matter by MBAS determination measuring the extinction of the trichloromethane solution at 642 nra. (a) Sultones. Connor et al. [130] first reported, in 1975, a very small amount of skin sensitizer, l-unsaturated-l,3-sultone, and 2-chloroalkane-l,3-sultone in the anionic surfactant produced by the sulfation of ethoxylated fatty alcohol. These compounds can also be found in some AOS products consequently, methods of detection are essential. 

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]. 

For a further separation of the sulfonated surfactants the latter are heated for 4 h with 2 N HC1. The methyl ester sulfonates are split into methanol and a-sulfo fatty acids, which form disodium salts after neutralization with NaOH. The product mixture from acid hydrolysis can be separated by extraction with petroleum ether. For example, the fatty alcohols formed from fatty alcohol sulfo-... 

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