Solubility alkyl ether sulfates

Alkyl Ether Sulfates These surfactants are also found in shampoo applications. They are prepared similarly to alkyl sulfates except that the fatty alcohol is first subjected to ethoxylation ethoxylation may range from 2 to 3 moles per mole of fatty alcohol. Lauryl alcohol is the typical fatty alcohol reacted. Because of high water solubility, alkyl ether sulfates have low cloud points, making them suited for clear shampoo formulations (5). Viscosities based on the ether sulfates can be easily controlled through addition of inorganic salts such as sodium chloride. 

Washing and Cleaning Action. The properties of alkyl ether sulfates, due to the good solubility and the special hydrophilic/hydrophobic properties of the molecule, are of particular practical interest. From the investigations described in sections 2 and 3, it can be concluded that, in addition to the decrease in the Krafft Point, favorable properties for practical applications can be expected as a result of the inclusion of the oxyethylene groups into the hydrophobic part of the molecule. As is true for other anionic surfactants, the electrical double layer will be compressed by the addition of multivalent cations. By this means, the adsorption at the interface is increased, the surface activity is raised, and, furthermore, the critical micelle concentration decreased. In the case of the alkyl ether sulfates, however these effects can be obtained without encountering undesirable salting out effects. 

Alkyl ether sulfates (AES) are anionic surfactants obtained by ethoxy-lation and subsequent salfation of alcohols derived from feedstock or synthetic alcohol. AES, also known as alcohol ether sulfates, have low sensitivity to water hardness (Fig. 5.3), high solubility, and good storage stability at low temperature [4, 11]. 

High-performance liquid chromatography is performed using a Hewlett-Packard 1090 chromatograph equipped with a ternary-solvent delivery system, an autoinjector with a 0 -20- u.L injection loop, an oven compartment, and a diode-array UV detector. An ELS detector (Alltech Associates, Deerfield, IL) is connected in series to the UV detector. Hexane, 2-propanol, and water were used for the analysis of nonionic surfactants. Water and tetrahydrofuran (THF) are used for the analysis of anionic surfactants. No preliminary sample preparation is used other than dilution. The nonionic surfactants are diluted 1 40 (v/v) with hexane. The anionic surfactants (alkyl ether sulfates and synthetic and petroleum sulfonates) are diluted 1 20 (v/v) with water-THF (50 50). The calcium sulfonate surfactants were diluted 1 20 (v/v) with a THF-38% hydrochloric acid solution of pH 1. Hydrochloric add is required to prevent salt precipitation by converting any excess water-insoluble caldum carbonate into water-soluble calcium chloride. All diluted samples are... 

Schwuger [4] has investigated the effects of ether groups on the solubility, surface properties, and detergency of alkyl ether sulfates. Addition of ethylene oxide groups to the alkyl surfactants increases solubility, thus reducing the formation of precipitates and maintaining foam volume in the presence of Ca2+ and Mg2+ ions. The use of ether sulfates would be preferred over that of alkyl sulfates for a clear formulation. 

Effects of ethoxylation of alkyl ether sulfates on solubility, surface properties, and detergency have been discussed in the literature. Ethoxylation of alkyl surfactants not only increases solubility, but also helps reduce the tendency for precipitation and decrease in foam volume in the presence of calcium and magnesium ions from hard water. 

Alkyl ether sulfates, also called alcohol ethoxysulfates, are prepared by addition of one to four oxyethylene groups to an alcohol which is then sulfated. Oxyethylation enhances water solubility and foaming over the analogous alcohol sulfate, giving a product useful in shampoos and in liquid and powdered detergents. The raw material for these products can be either natural fatty alcohols or primary or secondary synthetic alcohols, usually of C12-C18 chain length. The analogous alkylphenol ether sulfates are found in industrial applications. Ether sulfates are not as sensitive to water hardness as are other anionic surfactants. 

Surfactants used in the polymerization are water-soluble, halogenated surfactants. They are in particular fluorinated surfactant such as ammonium, substituted ammonium, quarternary ammonium, or alkali metal salts of perfluorinated or partially fluorinated alkyl carboxylates, monoalkyl phosphate esters, alkyl ether or polyether carboxylates, alkyl sulfonates, and alkyl sulfates. 

Papaverine crystallizes from ethanol as rhombic prisms or small white needles melting at 147-148°C. It is readily soluble in hot benzene, glacial acetic acid, ethanol, or petroleum ether, sparingly soluble in ether and carbon tetrachloride, and almost insoluble in water. It is a weakly monoacidic base and forms many salts with common acids, and metallic double salts. With alkyl halides, sulfates, etc., papaverine yields quaternary salts a number of addition products with acyl halides have also been described. 

In monoesters of sulfuric acid, the sulfate ion is the hydrophilic part of the molecule which results in its solubility in water. Sodium salts of fatty alcohol monoesters of sulfuric acid are the best known examples of this kind of surfactant. The sulfate group is also present in alkyl polyglycol ether sulfates and in some reaction products of starting materials containing a double bond or an OH-group in the molecule, e.g. sulfated castor oil. 

ISO 6842 defines total active matter as ethanol solubles, which includes not only the ether sulfate but also alkyl or alkylphenol sulfate, PEG sulfate, and unsulfated nonionic material including PEG (70). ISO 6843 describes wet chemistry methods for separately determining PEG, sulfonated PEG, and inorganic salts in order to arrive at a value for the ether sulfate itself, but this value will still include alkylsulfate or alkylphenolsulfate (71). 

Stabihty depends mosdy on purity, with purer materials having longer shelf Hves (1). For the higher alkyl groups, the anhydrous compounds are soluble and the monohydrates are insoluble in ether. Solutions in water are strongly ionized and acidic. The lower dialkyl sulfates are Hquids with faint but pleasant odors n-nonyX and higher normal aHphatic and cycHc sulfates are soHds. 

Cellulose ethers can be prepared by treating alkali cellulose with a number of various reagents including alkyl or aryl halides (or sulfates), al-kene oxides, and unsaturated compounds activated by electron-attracting groups. A variety of products of considerable commercial importance has been developed for different uses (Table 9-7). Most of the cellulose ethers are water soluble and they generally possess similar properties, but because... 

In application, the most important chemically modified CDs are the ether derivatives, such as hydroxypropyl-, methyl-, ethyl-CDs. These cyclodextrins etheric derivatives (CEDs) with the improved solubility, encapsulation ability and low toxicity have aheady been commercialized and widely used. The CEDs could be prepared in two ways. One way is that the CD reacts with the free hydroxyls such as dimethyl sulfate, diethyl sulfate, alkyl halides and epoxides. The other way is by sulfonic ester transformation. 

The substrate is dissolved in dichloromethane (1 10 to 1 50, w/v, depending upon the solubility at low temperature), and the solution is cooled to —10 °C. The solution is magnetically stirred while boron trifluoride etherate (1-3 drops, or its solution in dichloromethane) is added, followed by a solution of the diazoalkane in dichloromethane, until a faint yellow color persists for at least 5 min. The solution is stirred at below 0 °C, protected from atmospheric moisture, and further portions of the reagents are periodically added until a suitable test shows satisfactory conversion of the starting material into the alkylated product. The solution is filtered to remove any polymeric material formed as a by-product, and the filtrate is washed successively with a solution of sodium bicarbonate and water, dried over anhydrous sodium sulfate, and concentrated. 

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