Anionic sulfonate groups

Similar to tannins, the polycarboxylic acid group provides a chelating function that ties up metal ions. The anionic sulfonate group functionality confers both solubility and dispersing capability for multivalent cations (calcium, iron, etc.). 

In a variation on this theme cobaltphthalocyaninetetrasulfonate (CoPcTs) was bound via the anionic sulfonate groups to styrene-divinylbenzene copolymer latexes containing quaternary ammonium ions.46 The resulting colloidal catalyst was used to effect the autoxidation of 2,6-di-tert-butylphenol in aqueous solution, to the corresponding diphenoquinone (reaction 21). The rate of oxidation was ten times faster than with homogeneous CoPcTs in water. 

The size of the cavity plays a crucial role on the selectivity of the reaction. For example, when the esterification was performed with p-sulfonatocalix [4]arenes, the kcaiixarene/k HBS value for histidine was indeed increased from 24 to 86. 2H NMR studies supported the formation of an inclusion complex of caiixarenes with basic amino acids, and the reaction followed Michaelis-Menten kinetics. The specific rate enhancement observed for basic amino acids His 33, Lys 34 and Arg 35 is the result of a stabilization by the anionic sulfonate groups of the cationic intermediate, which can undergo esterification (see Scheme 13.8). In contrast, the formation of Phe 36, might proceed via simple acid catalysis. 

In Table 14-1 a Nafion 1 (sulfonated perfluoroalkyl polyanion polymer) membrane is often used since it is a stable cation-exchange polymer able to adsorb cationic compounds easily. A Nafion membrane is composed of hydrophilic columns incorporating anionic sulfonate groups, hydrophobic columns composed of main chains, and interlayer regions between the hydrophilic and hydrophobic columns. When a cationic substrate is adsorbed from an aqueous solution, the adsorbed material is located only in the hydrophilic columns or interlayer regions, so that a real local concentration of... 

Shortly after discovery of methods for preparation of organic soluble derivatives of poly(phenylene vinylene) and polythiophene, Wudl and coworkers reported preparation of each of these polymers with sulfonated side groups. The specific objective of this work was based on the idea that the anionic sulfonate groups could make the polymers self-doping , wherein the covalently linked anionic units could serve to provide charge compensation when the polymer backbone is in the oxidized (semiconducting) state. These first studies focused on the synthetic monomer and polymer chemistry. However, the authors reported in their papers that their newly synthesized conjugated... 

Amphoteric Detergents. These surfactants, also known as ampholytics, have both cationic and anionic charged groups ki thek composition. The cationic groups are usually amino or quaternary forms while the anionic sites consist of carboxylates, sulfates, or sulfonates. Amphoterics have compatibihty with anionics, nonionics, and cationics. The pH of the surfactant solution determines the charge exhibited by the amphoteric under alkaline conditions it behaves anionically while ki an acidic condition it has a cationic behavior. Most amphoterics are derivatives of imidazoline or betaine. Sodium lauroamphoacetate [68647-44-9] has been recommended for use ki non-eye stinging shampoos (12). Combkiations of amphoterics with cationics have provided the basis for conditioning shampoos (13). 

ACID DYES Commercial acid dyes contain one or more sulfonate groups, thereby providing solubility in aqueous media. These dyes are apphed in the presence of organic or mineral acids (pH 2—6). Such acids protonate any available cationic sites on the fiber, thereby making possible bonding between the fiber and the anionic dye molecule. Wool, an animal fiber, is an amphoteric coUoid, possessing both basic and acidic properties because of the amino and carboxylic groups of the protein stmcture. In order to dye such a system, coulombic interactions between the dye molecule and the fiber must take place ie, H2N" -wool-COO + H2N" -wool-COOH. The term acid dye is appHed to those that are capable of such interactions. Acid dyes... 

In view of this behavior, the next step involved a search for an anionic sohd that was more similar to triflate. Several organic polymers with sulfonic groups were tried as supports [52]. Dowex and Deloxan were used as supports for the enf-6a-Cu(II) complex. The solid catalysts were used in the same cyclopropanation reaction (Scheme 7) and some relevant results are gathered in... 

Surfactants are widely used in industrial chemistry to modify the behavior of aqueous solutions. Common surfactant head groups include carboxylate (— CO2), sulfonate (-SO3), sulfate (-OSO3 ), and ammonium (-NH3 ). The negative charge of anionic head groups usually is neutralized by Na , and the positive charge of ammonium usually is neutralized by Cl . These ions are used because they are nontoxic and their salts are highly soluble. 

Anionic galactomannans, which are derived from guar gum, in which the hydroxyl groups are partially esterified with sulfonate groups that result from 2-acrylamido-2-methylpropane sulfonic acid and l-allyloxy-2-hydroxypropyl sulfonic acid [1872], have been claimed to be suitable as thickeners. The composition is capable of producing enhanced viscosities, when used either alone or in combination with a cationic polymer and distributed in a solvent. 

Surfactants employed for w/o-ME formation, listed in Table 1, are more lipophilic than those employed in aqueous systems, e.g., for micelles or oil-in-water emulsions, having a hydrophilic-lipophilic balance (HLB) value of around 8-11 [4-40]. The most commonly employed surfactant for w/o-ME formation is Aerosol-OT, or AOT [sodium bis(2-ethylhexyl) sulfosuccinate], containing an anionic sulfonate headgroup and two hydrocarbon tails. Common cationic surfactants, such as cetyl trimethyl ammonium bromide (CTAB) and trioctylmethyl ammonium bromide (TOMAC), have also fulfilled this purpose however, cosurfactants (e.g., fatty alcohols, such as 1-butanol or 1-octanol) must be added for a monophasic w/o-ME (Winsor IV) system to occur. Nonionic and mixed ionic-nonionic surfactant systems have received a great deal of attention recently because they are more biocompatible and they promote less inactivation of biomolecules compared to ionic surfactants. Surfactants with two or more hydrophobic tail groups of different lengths frequently form w/o-MEs more readily than one-tailed surfactants without the requirement of cosurfactant, perhaps because of their wedge-shaped molecular structure [17,41]. 

These reactions accomplish the same overall synthetic transformation as the acylation of ester enolates, but use desulfurization rather than decarboxylation to remove the anion-stabilizing group. Dimethyl sulfone can be subjected to similar reaction sequences.232... 

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