Cationic surfactants consumption

CE has been used for the analysis of anionic surfactants [946,947] and can be considered as complementary to HPLC for the analysis of cationic surfactants with advantages of minimal solvent consumption, higher efficiency, easy cleaning and inexpensive replacement of columns and the ability of fast method development by changing the electrolyte composition. Also the separation of polystyrene sulfonates with polymeric additives by CE has been reported [948]. Moreover, CE has also been used for the analysis of polymeric water treatment additives, such as acrylic acid copolymer flocculants, phosphonates, low-MW acids and inorganic anions. The technique provides for analyst time-savings and has lower detection limits and improved quantification for determination of anionic polymers, compared to HPLC. 

Numerous laboratory sorption studies have been conducted for the most common surfactants non-ionics, such as AE and alkylphenol ethox-ylates (APEOs) anionics such as LAS, secondary alkane sulfonates (SASs) and sodium dodecylsulfates (SDS) and on different natural sorbents [3,8,15-17], Until now, cationic and amphoteric surfactants have received less study than the other types, probably because they represent only 5 and 2%, respectively, of the total surfactant consumption in Western Europe (1998) [18]. 

For this group of antifoams an effective way of application is in the form of foams [7]. For example, a foam stabilised by cationic surfactants is introduced in the foam to be destructed, obtained from an anionic surfactant solution. The cationic surfactant solution usually contains a considerable amount of calcium or aluminium salts. The large consumption of substances should be considered as a disadvantage of this group of antifoams. Furthermore,... 

In commercial alkylation one generally finds that improved reaction conditions lead to more selective and higher octane product, less acid consumption and higher yields based on olefin fed to the unit. Analyses of the spent acid obtained in the pilot plant also Indicate that acid consumption is strongly reduced when the cationic surfactants are used. 

Acid Consumption Reduced With Cationic Surfactants... 

Cationic surfactants represent one of the smaller classes of surfactants, with a consumption estimated to be 700000 tons per year. Typically, reviews and market studies include in this class of materials all amine-based surfactants, whether they be charged or uncharged. In this present chapter we will use the same definition, but exclude amphoteric materials, which will be covered in the next chapter in this volume. 

In contrast to anionic and nonionic surfactants, the consumption of cationic surfactants is much smaller. Cationic surfactants are mainly used as fabric softeners and in cleaners with biocide effects. Cationic compounds with different chemical structures which are used as surfactants include the following ... 

Foam films stabilized by anionic surfactants can be destroyed by the addition of an oppositely charged inorganic species or near-stoichiomeric concentrations of metallic ions to form insoluble salts. For example, fatty acids and their derivatives (tall oil, stearate, etc.) can be precipitated by the addition of calcium, aluminium and zinc salts (forming insoluble salts of the acids). There have been several attempts to relate the defoaming action to the solubility product of the particles. A typical series of results for metal oleates are shown in Figure 8.4. The influence of hydrophobic calcium fatty acid soaps on foaming, and quantification of the data in terms of the solubility product of the calcium and sodium fatty acids have also been reported. Cationic surfactants added to foam stabilized by anionic surfactants could also destroy the foam. Unfortunately, due to the formation of solid contaminants and the adverse consumption of chemicals, precipitation antifoamers are used infrequently in industry. 

About 60% of the fatty alcohols produced in 2006 were oleo based and this is expected to grow to about 65% by 2011. Oleochemical alcohols are particularly competitive in Asia due to the abundance of palm and coconut oils [39]. The consumption of cationic surfactants made by the various processes is shown in Table 2.2, and the impact of ester quats for fabric softening is clearly reflected in the numbers for cationics made via the fatty acid route. 

A reexamination of so-called renewabdity has shown that advantages for oleochemicals are not sufftcientiy clear (115), especially because manufacture of surfactants ia the United States accounts for only 0.03% of aimual cmde oil consumption (62). On these bases, the primary determinants of surfactant choice will continue to be cost effectiveness and availability. The 1993 U.S. market has been estimated to be worth 3.7 x 10 (110). Approximately one-half was anionic surfactant ( 1.8 x 10 ) and one-third nonionic surfactant ( 1.2 x 10 ). The balance was made up by cationics ( 1.2 X 10 ) and amphoterics ( 600 x 10 ). The U.S. International Trade Commission (116) provides a minutely detailed breakdown of surfactant production. 

The trend of discovering the analytical field of environmental analysis of surfactants by LC-MS is described in detail in Chapters 2.6-2.13 and also reflected by the method collection in Chapter 3.1 (Table 3.1.1), which gives an overview on analytical determinations of surfactants in aqueous matrices. Most methods have focused on high volume surfactants and their metabolites, such as the alkylphenol ethoxylates (APEO, Chapter 2.6), linear alkylbenzene sulfonates (LAS, Chapter 2.10) and alcohol ethoxylates (AE, Chapter 2.9). Surfactants with lower consumption rates such as the cationics (Chapter 2.12) and esterquats (Chapter 2.13) or the fluorinated surfactants perfluoro alkane sulfonates (PFAS) and perfluoro alkane carboxylates (PFAC) used in fire fighting foams (Chapter 2.11) are also covered in this book, but have received less attention. 

The primary factors Horn44 considers in his framework are gut length, gut pH, and microbial activity (Table 11.1). Besides these, other factors are also proving to be part of the complex mixture of variables that are important in herbivorous fish digestion. These other factors include specific endogenous and exogenous digestive enzymes in the gut, redox state, concentration, and activity of surfactants, and concentration and activity of cations. Gut transit time or evacuation rate is also considered an important factor because it influences assimilation efficiency and consumption rates.39-52-53... 

A recent paper by a Rusian team [18] describe tte use of a few new surfiners, one being cationic, namely JV-decylaceto-2-methyl-5 vinylpyridinium bromide (V), and the others being anioic, namely decyl (or dodecyl), sodium ethyl sulfonate, methacrylamides (VI), decyl (or dodecyl)-phenyl (Na or K sulfonate) acrylate (VII), and decyl ester of sodium (or K or NH4) sulphocin-namic acid (VIII). These surfmers were used for emulsion polymerization of styrene, butylacrylate or chloroprene, in the presence of KPS or AIBN without any other surfactants. It should be noted that the consumption of these surfactants take place early in the polymerization process which is faster than in... 

Amphoteric surfactants have a special application profile which favours their use mainly in cosmetics. In recent years, they have also found increasing application in the development of dishwashing agents or household cleaners. Compared to the amounts produced world-wide of anionic and nonionic surfactants, the volume of amphoterics is still relatively small. For cosmetic products, their consumption in Europe in 1992 was about 15 000 t. The main carbon chain includes the Cg-Cig range. The zwitterionic character of amphoterics strongly influences their particular behaviour, i.e. both anionic and cationic... 

The illumination of TMB in the presence of electron acceptors with different j-values yields TMB radical cations with different quantum yields and consumption of the spin label. The highest quantum yield was obtained with j = 10 and especially with j = 16. This was explained in terms of TMB location in the hydrophobic region of the micelle asymmetrically to the electron acceptor molecule. However, another interpretation is possible as the stearic acid molecule does not coincide in the number of carbon atoms with the micelle-forming surfactant, one can assume that the carbon atom C-13 is located near the end of the methyl groups of the surfactant, i.e. near the centre of the micelle. In this case the results of Bales and Kevan show that TMB molecules are located inside the micelle symmetrically with the photoionization probabihty maximum near the third carbon atom from the micelle centre. Anyway, TMB molecules are located in hydrophobic nuclei of the micelles. The important... 

The consumption of surfactants in Western Europe is estimated to be more than 1 million tons/year. As shown in Fig. 10, about 60% of this quantity are anionic surfactants (above all LAS), and the remainder is divided into about V4 of nonionics and % of cationics or amphoteric surfactants. 

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