Alkyl sulfates characterization

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). 

Hirata M, Yamada Y, Kokufuta E. Effects of pH and alkyl sulfate surfactants on swelling equilibria for a cationic polyelectrolyte gel from poly-(ethyleneimine). In Schmitz K, ed. Macro-ion Characterization from Dilute Solutions to Complex Fluids. ACS Symp Ser, No 548. Washington DC Amer Chem Soc, 1994 493-498. 

Quatemization involves the reaction of a tertiary amine with an alkylating agent. Typically, primary and some secondary alkyl halides are used for this purpose, although alkyl sulfates have also been used. Tertiary hahdes are not useful because they undergo elimination rather than substitution. The reaction, which is an example of an Sn2 process, proceeds readily to give crystalline, stable, and still-aromatic quaternary salts (Scheme 6.6). These have been used for many years to characterize amines. Acyl halides also react in a similar manner with pyridine, but the resulting salts are unstable and generally not isolated. 

It is only a small step from the alkyl sulfates to the so-called alkyl ether sulfates. These surface-active agents are made from alcohols which are ethoxylated. The formed fatty alcohol polyglycol ethers possess a final OH-group which then reacts with sulfuric acid. Fatty alcohol polyglycol sulfates are characterized by an insensitivity to water hardness and low irritation of the skin. Their aqueous solutions can be easily thickened by the addition of sodium chloride. These properties thus attract attention for the use of fatty alcohol polyglycol sulfates in cosmetic products. 

Three generations of latices as characterized by the type of surfactant used in manufacture have been defined (115). The first generation includes latices made with conventional (1) anionic surfactants such as fatty acid soaps, alkyl carboxy-lates, alkyl sulfates, and alkyl sulfonates (116) (2) nonionic surfactants such as... 

IC-MS has also been applied for the characterization of ionic liquids (IL) and for the investigation of their long-term stability under process-like conditions. The term ionic liquid commonly refers to a class of molten salts that are by definition liquid below 100 °C. They usually consist of bulky organic cations such as alkylated imidazole, pyrrole, or pyridine derivatives, or quatemized alkyl amines and alkyl phosphines. Common counterions are halides, alkyl sulfates, fluorinated hydrocarbons, carboxylic acids, or amino acids [268]. The physical and chemical properties of ILs are customizable by different cation-anion combinations and by the length of the alkyl chain of the cation. Depending on the... 

GC methods are summarized in Tables 2 and 3. Sulfates of alcohols and ethoxylated alcohols are readily decomposed by acid hydrolysis to yield the free alcohols or ethoxylated alcohols. The trimethylsilyl derivatives of these are easily analyzed by gas chromatography (24). Derivatization of the alcohols may be omitted if they have reasonable volatility (25). Alternatively, the surfactant may be decomposed by hydriodic acid, giving alkyl iodide derivatives of the starting alcohols for characterization by gas chromatography (26). Hydrolysis can be combined in the same step with derivatization. Reaction of alkyl sulfates with silylating agents such as BSTFA/1% TMCS results in cleavage of the sulfate and formation of the trimethylsilyl ethers of the alcohols (27). GC or GC-MS analysis will... 

The initial studies of LSDAs were carried out with oleochemicals because of their structural similarity to soap. However, since the molecular structure of an efficient LSDA is characterized by a bulky hydrophilic polar head attached to a long hydrophobic tail, it is also possible to prepare LSDAs from petrochemicals. Sulfated sulfonamide derivatives of alkylbenzenes, such as commercially available detergent alkylates, were synthesized as follows [17] ... 

A wide range of anionic surfactants (Fig. 23) has been classified into groups, including alkyl benzene sulfonates (ABS), linear alkyl benzene sulfonates (LAS), alcohol sulfates (AS), alcohol ether sulfates (AES), alkyl phenol ether sulfates (APES), fatty acid amide ether sulfates (FAES), alpha-olefin sulfates (AOS), paraffin sulfonates, alpha sulfonated fatty acids and esters, sulfonated fatty acids and esters, mono- and di-ester sulfosuccinates, sulfosuccinamates, petroleum sulfonates, phosphate esters, and ligno-sulfonates. Of the anionic surfactants, ABS and LAS continue to be the major products of anionic surfactants [314, 324]. Anionic surfactants have been extensively monitored and characterized in various environmental matrices [34,35,45,325-329]. 

Feijtel, T.C.J. and Belanger, S.E. (1999) Predicted no-effect concentrations and risk characterization of four surfactants linear alkyl benzene sulfonate, alcohol ethoxylates, alcohol ethoxylated sulfates, and soap. Environ Toxicol Chem, 18, 2653-2663. 

Several sulfated polyhydroxysterols have been recently isolated from sponges. Most of these natural products are characterized by the 2p,3a,6a-tri-0-sulfate functions together with additional alkylation in the side chain. These steroids are of interest not only because of their structures but... 

Many of the iV-alkyl and iV-aryl derivatives of urazine have been synthesized and characterized, but the parent substance is not well known. In the past, urazine has been prepared by thermal deammonation of carbohydrazide-iV-carboxamide [eq. (I)],1 fusion of hydrazidicarbamide with hydrazinium hydrogen sulfate [eq. (2)],2 fusion of earbohy-drazide with urea [eq. (3)],3 action of sodium hypobromite on semicarbazide [eq. (4)],4 reaction of dichlorourea with concentrated ammonia [eq. (5)],5 and the reaction between 1,2 hydrazine carboxylic ester and hydrazine hydrate... 

V. Bernabe-Zafon, S. Ortega-Gadea, E.F. Sim6-Alfonso and G. Ramis-Ramos, Characterization and quantitation of mixtures of alkyl ether sulfates and carboxylic acids by capillary electrophoresis with indirect photometric detection. Electrophoresis, 24, 2805-2813, 2003. 

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