Surfactant quaternary ammonium cation

Cationic Surfactants Quaternary ammonium cationic surfactants with alkyl groups of Ci6 to C22 with organic counterions have been smdied extensively [Chou, 1989b] and have been shown to be effective at concentrations as low as 50 ppm [Kawaguchi et al., 2003]. This effectiveness is enhanced by increasing the surfactant concentration and by increasing the counterion/cation ratio, f. 

Cationic surfactants Quaternary ammonium compounds (QACs)h ... 

Quaternary ammonium cationic surfactants, such as DTDMAC, were determined in digested sludge by using supercritical fluid extraction (SFE) and FIA-ESI-MS(+) after separation by normal phase LC. Standard compounds—commercially available DTDMAC— were used to check the results. The DTDMAC mixture examined showed ions at m/z 467, 495, 523, 551, and 579 all equally spaced by A m/z 28 (-CH2-CH2-) resulting from the ionisation of compounds like RR N (CH3)2 X (R = / RO as shown in Fig. 2.12.11(a) and (b) [22],... 

Glasses exist that fnnction as selective electrodes for many different monovalent and some divalent cations. Alternatively, a hydrophobic membrane can be made semiper-meable if a hydrophobic molecnle called an ionophore that selectively binds an ion is dissolved in it. The selectivity of the membrane is determined by the structnre of the ionophore. Some ionophores are natnral products, such as gramicidin, which is highly specific for K+, whereas others such as crown ethers and cryptands are synthetic. Ions such as, 1, Br, and N03 can be detected using quaternary ammonium cationic surfactants as a lipid-soluble counterion. ISEs are generally sensitive in the 10 to 10 M range, but are not perfectly selective. The most typical membrane material used in ISEs is polyvinyl chloride plasticized with dialkylsebacate or other hydrophobic chemicals. 

PCH materials offer new opportunities for the rational design of heterogeneous catalyst systems, because the pore size distributions are in the supermicropore to small mesopore range (14-25A) and chemical functionality (e.g., acidity) can be introduced by adjusting the composition of the layered silicate host. The approach to designing PCH materials is based on the use of intercalated quaternary ammonium cations and neutral amines as co-surfactants to direct the interlamellar hydrolysis and condensation polymerization of neutral inorganic precursor (for example, tetraethylorthosilicate, TEOS) within the galleries of an ionic lamellar solid. 

Abele, S., Zicmanis, A., Graillat, C., Monnet, C. and Guyot, A. (1999) Cationic and zwitterionic polymerizable surfactants Quaternary ammonium diatkyl maleates. 1. Synthesis and characterization. Langmuir, 15, 1033-44. 

To synthesize water-soluble or swellable copolymers, inverse heterophase polymerization processes are of special interest. The inverse macroemulsion polymerization is only reported for the copolymerization of two hydrophilic monomers. Hernandez-Barajas and Hunkeler [62] investigated the copolymerization of AAm with quaternary ammonium cationic monomers in the presence of block copoly-meric surfactants by batch and semi-batch inverse emulsion copolymerization. Glukhikh et al. [63] reported the copolymerization of AAm and methacrylic acid using an inverse emulsion system. Amphiphilic copolymers from inverse systems are also successfully obtained in microemulsion polymerization. For example, Vaskova et al. [64-66] copolymerized the hydrophilic AAm with more hydrophobic methyl methacrylate (MMA) or styrene in a water-in-oil microemulsion initiated by radical initiators with different solubilities in water. However, not only copolymer, but also homopolymer was formed. The total conversion of MMA was rather limited (<10%) and the composition of the copolymer was almost independent of the comonomer ratio. This was probably due to a constant molar ratio of the monomers in the water phase or at the interface as the possible locus of polymerization. Also, in the case of styrene copolymerizing with AAm, the molar fraction of AAm in homopolymer compared to copolymer is about 45-55 wt% [67], which is still too high for a meaningful technical application. 

Hernandez-Barajas J, Hunkeler DJ (1997) Inverse-emulsion copolymerization of acrylamide and quaternary ammonium cationic monomers with block copolymeric surfactants copolymer composition control using batch and semi-batch techniques. Polymer 38(2) 449—458... 

Cetylpyridinium chloride is a quaternary ammonium cationic surfactant, used in pharmaceutical and cosmetic formulations as an antimicrobial preservative see Section 10. It is used therapeutically as an antiseptic agent used alone or in combination with other drugs for oral and throat care used in nonparenteral formulations licensed in the UK and used in oral and inhalation preparations at concentrations of 0.02-1.5 mg (see Section 16). 

Cationic surfactants (quaternary ammonium group) and amphoteric surfactants with a long alkyl chain present a poor absorption in UV. 

Ion flotation in the presence of surfactants for the treatment of rinses and separation of metal ions is of interest since the sixties [327, 328]. Here, we take only a few examples. The recovery of silver ions from highly diluted solutions is possible by forming a silver-thiourea complex in form of a colloidal precipitate (sublate) followed by sublate flotation with sodium dodecyl benzene sulfonate [329]. Skiylev [330] has developed methods for the removal of non-ferrous metal salts from waste waters. Subject of the investigations were 0.01 - 0.001% solutions of ferrous metal salts. Typical anionic surfactants (alkyl sulfates, alkyl phosphates, alkyl xanthogenates of potassium) or cationic surfactants (quaternary ammonium salts) were used as collectors in ion flotation from diluted solutions. At certain pH, a sublate containing a non-ferrous metal ion was formed, followed by a sublate film formation at the surface due to the rise of the complexes with air bubbles stabilised by the surfactants. 

Zwitterionic surfactants, also known as amphoteric surfactants, have both cationic and anionic centers present in the same molecule. Generally, their properties are highly dependent on the pH of the solution. The cationic part is based on primary, secondary, or tertiary amines or quaternary ammonium cations. The anionic part can be more variable and include sulfonates, as in CHAPS (3-[(3-Cholamidopropyl)dimethylammonio]-l-propanesulfonate). Other anionic groups are sultaines illustrated by cocamidopropyl hydroxysultaine. Examples of zwitterionic surfactants include betaines (such as cocamidopropyl betaine, dodecyl betaine, lauramidopropyl betaine and cocoamido-2-hydroxypropyl sulfobetaine) and phosphates (such as lecithin). 

Some of these surfactant-encapsulated polyoxometalate complexes exhibited liquid-crystaUine behavior. Paul and coworkers obtained room temperature LCs by complexation of the sandwiched europium-containing polyoxometalate [Eu(SiW9Mo2039)2] with a series of cationic surfactants (Zhang et al., 2005). For the quaternary ammonium cations with one long chain a hexagonal (columnar ) phase and possibly a cubic phase were observed, whereas for the quaternary ammonium cation with two long chains... 

Cationic surfactants, characterized by their amphiphilic properties, contain an alkyl hydrophobe and a hydrophilic positively charged head-group. Among cationic surfactants, quaternary ammonium salts are notable for their ability to reduce surface and interfacial tensions by ready adsorption to a surface or interface, such as hair and skin. This ability to adsorb on to substrates makes the use of cationic surfactants extremely important in the personal care industry. 

The use of inorganic mineral products as oil sorbents requires in most cases their chemical or surface modification, in order to ameliorate their hydrophobic character and affinity for organic compoimds. For example, modification with CF3-(CH2)2-groups can be used, in order to limit the structure collapse of silica aerogels due to water adsorption, resulting in an excellent oil sorption capacity. Cationic surfactants, such as quaternary ammonium cations can be applied in order to ameliorate the oil sorption capacity of inorganic materials, such as zeolites, clays and fly ash [30-38],... 

Cationic surfactants, characterized by their amphiphilic properties, contain an alkyl hydrophobe and a hydrophilic positively charged head group. Among cationic surfactants, quaternary ammonium salts are notable for... 

Two-dimensional LC to determine anionic surfactants (types of carboxylates, sulfates and sulfonates), cationic surfactants (quaternary ammonium and alkyl pyridinium salts) and amphoteric surfactants (amidobetaines) was proposed by Noguchi et al. (1998). First column (anion exchange column for anionics and cation exchange column for cationic and amphoteric surfactants) separated according to functional group and a second column (octadecylsilica) allowed the separation of alkyl homologues. The method was applied to shampoo. 

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