Sulfated surfactants alcohol sulfates

Alkyl ether sulfates with chain lengths ranging from to Cw are quantitatively the most important products currently based on fatty alcohols. It is estimated, that about 20 % of all surfactant alcohols -about 40 % of all fatty alcohols in the coconut range (C,2 Ci,) - are used in the form of alkyl ether suirateg ( ). Alkyl ether sulfates are the most important group of anionic surfactants after linear alkyl-benzenesulfonate (LAS) (2). 

Anon. (1991) Environmental and Human Safety of Major Surfactants. Volume 1 Anionic Surfactants. Part 1. Linear Alkylbenzene Sulfonates. Part 2. Alcohol Ethyl Sulfates. Part 3. Alkyl Sulfates. Part 4. Alpha Olgin Sulfonates. Volume 2 Nonionic Surfactants, Alcohol Ethoxylates and Alkylphenol Ethoxylates. Government Reports Announcements Index (GRA I). 

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). 

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. 

Ethoxylated Sulfate Surfactants onto Mineral Oxides and Sandstone Cores. Various features of anionic surfactant systems in EOR have been illustrated in a series of studies using ethoxylated sulfates as the primary surfactants with additives which included co-surfactants, alcohols, electrolytes, polyethylene oxide and polymers [63-70], The solids included kaolinite, quartz, sandstone cores, Berea cores, and oil containing reservoir cores. 

We have studied three model systems of five-component mixtures oil -water - surfactant - alcohol - salt. Three different ionic surfactants have been used dodecyltrimethyl ammonium bromide (DTAB), sodium dodecyl sulfate (SDS) and sodium hexadecyl benzene sulfonate (SHBS). The alcohol used was butanol its addition was necessary because the above surfactants alone could form microemulsions. The salt screened the electrostatic interactions between surfactant polar heads it reduced Cq In this way, a continuous structural evolution o/w - bicontinuous - w/o could be obtained by addition of salt. At each salinity, the size of the structural elements was the largest (maximum swelling Rq for droplets, bicontinuous structures) because the microemulsions coexisted with excess oil and/or water. 

Of the innumerable surfactant/alcohol/water systems studied in the past, mainly two others will be drawn on for comparison. The first one is the system SDS/CA-SA/water studied by Awad and coworkers [1] at a water concentration of 89 wt%. These authors used a fatty alcohol mixture with a mass ratio CA SA = 1 1.18. The second system, investigated by Schipunov [38], contains a varying ratio of the surfactant N-(2-hydroxyethyl)dodecane amide (CMEA) and the fatty alcohol CA, about 90 wt% water, and 1 wt% of the additional surfactant sodium-2-[2-dodecoxyethoxy]-ethyl-sulfate (SLES). We will refer to this system as the CMEA/CA/water system. 

The detergent range alcohols and their derivatives have a wide variety of uses ia consumer and iadustrial products either because of surface-active properties, or as a means of iatroduciag a long chain moiety iato a chemical compound. The major use is as surfactants (qv) ia detergents and cleaning products. Only a small amount of the alcohol is used as-is rather most is used as derivatives such as the poly(oxyethylene) ethers and the sulfated ethers, the alkyl sulfates, and the esters of other acids, eg, phosphoric acid and monocarboxyhc and dicarboxyhc acids. Major use areas are given ia Table 11. 

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). 

Three generations of latices as characterized by the type of surfactant used in manufacture have been defined (53). The first generation includes latices made with conventional (/) anionic surfactants like fatty acid soaps, alkyl carboxylates, alkyl sulfates, and alkyl sulfonates (54) (2) nonionic surfactants like poly(ethylene oxide) or poly(vinyl alcohol) used to improve freeze—thaw and shear stabiUty and (J) cationic surfactants like amines, nitriles, and other nitrogen bases, rarely used because of incompatibiUty problems. Portiand cement latex modifiers are one example where cationic surfactants are used. Anionic surfactants yield smaller particles than nonionic surfactants (55). Often a combination of anionic surfactants or anionic and nonionic surfactants are used to provide improved stabiUty. The stabilizing abiUty of anionic fatty acid soaps diminishes at lower pH as the soaps revert to their acids. First-generation latices also suffer from the presence of soap on the polymer particles at the end of the polymerization. Steam and vacuum stripping methods are often used to remove the soap and unreacted monomer from the final product (56). 

Cosurfactant requirements can be minimized usiag a surfactant having a short-branched hydrophobe or a branched-alkyl substituent on an aromatic group (232,234) and a long ethoxy group chain (234). Blends of surfactants optimized for seawater or reservoir brine salinity include linear alkyl xylene sulfonate—alcohol ether sulfate mixtures (235). 

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). 

Long-chain alcohols, such as are obtained by the hydrogenation of coconut oil, polymerization of ethylene, or the 0x0 process (qv), are sulfated on a large scale with sulfur thoxide or chlorosulfuhc acid to acid sulfates the alkaU salts are commercially important as surface-active agents (see Surfactants). Poly(vinyl alcohol) can be sulfated in pyhdine with chlorosulfuhc acid to the hydrogen sulfate (84). 

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). 

Poly(vinyl acetate) emulsions can be made with a surfactant alone or with a protective coUoid alone, but the usual practice is to use a combination of the two. Normally, up to 3 wt % stabilizers may be included in the recipe, but when water sensitivity or tack of the wet film is desired, as in some adhesives, more may be included. The most commonly used surfactants are the anionic sulfates and sulfonates, but cationic emulsifiers and nonionics are also suitable. Indeed, some emulsion compounding formulas require the use of cationic or nonionic surfactants for stable formulations. The most commonly used protective coUoids are poly(vinyl alcohol) and hydroxyethyl cellulose, but there are many others, natural and synthetic, which are usable if not preferable for a given appHcation. 

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],... 

Table 6 shows a comparison of commercially produced C, 4 LAS samples in a current North American light-duty liquid (LDL) formulation containing more than 20% LAS together with alcohol ether sulfate (AES), amide, and hydrotrope. The highest viscosity is observed with the high 2-phenyl/low DATS sample, whereas the high 2-phenyl/high DATS sample had the lowest viscosity. The DATS provides the dual function of surfactant and hydrotrope. 

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