Containing Anionic Functional Groups

Anionic surfactants are those which contain anionic functional groups at their head, such as sulfate, sulfonate, and carboxylates. Their relatively lower cost makes them the most songht-after surfactant in the industry. Table 13.3 mentions the anionic surfactants nsed in the formulation of microemulsions. 

Dyes Containing Anionic Functional Groups Acid dyes Direct dyes Mordant dyes Reactive dyes... 

In addition to the substituents listed in Scheme 1, chiral groups may be introduced and unsymmetrically substituted amidinate anions are also possible. The amidinate anions may also contain additional functional groups, or two such anions can be linked with or without a suitable spacer unit. Yet another variety comprises the amidinate ligands being part of an organic ring system. All these aspects will be covered in the present review. 

This separation technique produces very good results for acidic or anionic dye molecules containing carboxylic, sulfonic, and hydroxy groups that can be separated within short run times in an aLkaline medium in a single analysis step. - Natural colorants usually do not contain these functional groups they are usually more voluminous and strongly hydrophobic, properties that complicate their determination by CE. The sample pretreatment is more difQcult when CE (compared to HPLC) is used. 

Ion bridging is a specific type of Coulombic interaction involving the simultaneous binding of polyvalent cations (e.g., Ca, Fe, Cu ) to two different anionic functional groups on biopolymer molecules. This type of ionic interaction is commonly involved in associative self-assembly of biopolymers. As a consequence it is also an important contributory factor in the flocculation (via bridging or depletion) of colloidal particles or emulsion droplets in aqueous media containing adsorbed or non-adsorbed biopolymers (Dickinson and McClements, 1995). 

Diamond surfaces after anodic oxidation treatment involve oxygen-containing surface functional groups. The electron-transfer kinetics for ions and polar molecules are expected to be quite different. Fe(CN)l /4 was highly sensitive to the surface termination of diamond. For an anionic reactant, there was an inhibition of the electron transfer for the oxygen-terminated diamond electrodes compared with the hydrogen-terminated diamond electrodes, and there was also an acceleration of the electron transfer for oxygen-terminated diamond for some cationic reactants such as Ru(NH3) +/3+ and Fe2+/3+. These results can be explained by electrostatic effects, which interact between the ionic... 

Among the NHC ligands with N-substituents containing centers of chirality, polydentate ligands that combine the NHC unit with an anionic functional group have been developed recently. They thus combine two complementary ligating anchor units, which avoids the rotation of the chiral substituents around the C - N axis. Arnold and coworkers reported the synthesis of the... 

Wool and silk contain charged functional groups, such as NH3 and COO . Because of this, they bind to ionic dyes by electrostatic interactions. For example, positively charged NH3 groups bonded to the protein backbone are electrostatically attracted to anionic groups in a dye like methyl orange. 

The chemistry of sulfoximides (sulfoximines) is somewhat related to that of sulfones. - - Although several methods are available for the preparation of free sulfoximines from di- and tri-valent sulfur compounds, the methods are of limited applicability when the desired sulfoximines contain labile functional groups. An alternative approach involving alkylating the readily available anion derived from N-suh-stituted methylsulfoximides has been described but preparation of the free sulfoximides has proved... 

The organic ion exchangers are obtained by co-polymerization. They contain ionizable functional groups. The functional groups in cation exchangers are -SO3H, -COOH, and -OH those in anion exchangers are -NRs, -NR2, -NHR, and NH2. 

---