Solubilizers complexing agents

Simplest examples are prepared by the cyclic oligomerization of ethylene oxide. They act as complexing agents which solubilize alkali metal ions in non-polar solvents, complex alkaline earth cations, transition metal cations and ammonium cations, e.g. 12—crown —4 is specific for the lithium cation. Used in phase-transfer chemistry. ... 

Electrodeposition of antimony sesquitelluride, Sb2Tc3, or of (Bii xSbx)2Te3 alloys from aqueous solutions is challenging because it is difficult to achieve a sufficiently high concentration of antimony. Complexing agents such as tartaric acid, citric acid, or FUTA have been used to solubilize Sb in water. 

The foregoing sections have dealt with the nucleophilic properties of anionic species whose salts were solubilized in apolar solvents with the aid of cation-complexing agents. Apart from the nucleophilic character of the anion, however, its basic strength is also expected to increase with decreasing extent of solvation. This section will deal with hydrogen-abstraction reactions of crown ether-solubilized bases. 

Pierre and Handel (1974) observed that cyclohexanone was cleanly reduced to cyclohexanol by LiAlH4 in diglyme solution. On addition of one equivalent (based on Li+) of the strong Li+-complexing agent [2.1.1]-cryptand, all the LiAlH4 was solubilized, but the reduction was completely inhibited. In the presence of additional amounts of either Lil or Nal, the ketone was reduced in the normal way. On the basis of these results, the authors concluded that the... 

For oral liquids, taste masking becomes essential. The effects of solubilizing agents such as complexing agents and cosolvents on taste need to be evaluated. 

Hamza, Y. E. and M. Kata. 1989. In uence of certain hydrotropic and complexing agents on solubilization of allopurinol.Pharm. Ind.51 1159-1162. 

Nevertheless, solubilization still could be required for very insoluble molecules. Several approaches have been reported. Use of cyclodextrin as a complexation agent was shown to be effective and yielded both accelerated and pH-independent release.48 Further, in situ complexation between drug molecules and cyclodextrin in the matrix was encouraging because it would not require organic processing to render such complexation prior to matrix preparation. Recently, other approaches, such as incorporating... 

Lipids also can be beneficial for cells in culture, since some substances absorbed by the cells need to be solubilized in lipids, or in some cases the toxicity of compounds may be reduced by complexation with lipids. The absence of essential lipids such as linoleic acid, lecithin, cholesterol, ethanolamine, or phosphorylcholine can result in the decrease of cloning efficiency and in reduction in the size of colonies, as shown for insect cells by Echalier (1997). However, one of the difficulties in supplying lipids at reasonable concentrations is their low solubility. To circumvent this limitation, lipids can be emulsified with complexing agents such as Pluronic F68 or cyclodextrin (Maiorella et al., 1998). 

Type 2 facilitation is also known as carrier facilitated transport, since a carrier compound, that is, an extractant or complexing agent, solubilized in the organic phase is used to assist transfer across the membrane. In this simation, the solute of interest reacts with the carrier to form a complex that is only soluble in the membrane phase. The solute is de-complexed by a stripping solution contained in the internal phase. An example of such a process is the removal of a metal ion such as copper or zinc from wastewater by the extractant DEHPA (di-2-ethyUiexyl phosphoric acid, represented as HE) as shown in Figure 25.2. In this case, the carrier also enhances the selectivity as most extractants are specifically designed to extract particular metal ions... 

Schalscha, E.B., Appelt, H. and Schatz, A., 1967. Chelation as a weathering mechanism-1. Effect of complexing agents on the solubilization of iron from minerals and grano-diorite. Geochim. Cosmochim. Acta, 31 587—596. 

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