Complexing agents for metals

Acetone cyanohydrin is used as a raw material for insecticides manufacture and also to produce ethyl a-hydroxyisobutryate [80-55-7], a pharmaceutical intermediate. It has been used as a complexing agent for metals refining and separation. Acetone cyanohydrin complexes can be used to separate, Cu , , 7x5, Cd , or Fe from Mg , , Ca , Na , or on strongly basic ion-exchange resins (31). Acetone cyanohydrin is... 

Used industrially in organic synthesis, in the manufacture of insecticides and pharmaceuticals, as an intermediate in the synthesis of methacrylates used as a complexing agent for metals refining and separation. 

Periodic mesoporous silicas were reported for the first time in the literature by researchers at the Mobil Oil Corporation in the early 1990s, although a synthetic process that yields very similar reaction products was patented twenty years prior (MoUer and Bein, 1998). The reactive internal surfaces of these solids have been used to attach functional groups that can act as complexing agents for metal cations. However, as well as complexation and similar uses like ion exchange and sorption, the channels have been used to grow metal clusters and wires. 

Ring size of macroheterocycles and their activity as complexing agents for metal ions 86PAC1445. 

Figure 19.6 Typical ccdibration curve of an ISE by direct potentiometry. The calibration curve of the specific electrode for the chloride ion has almost an ideal slope value. The range of linear response for the different ISE extends over 4 to 6 orders of magnitude depending on the ion. Expression 19.5 leads to the estimation that an uncertainty of 0.2 mV on E leads to an inexactness of 0.8 per cent in the concentration (for a monovalent ion). Here, the TISAB consists of NaCl 1 M for adjusting the ionic force, a complexing agent for metals and a hufler mixture of acetic acid/sodium acetate.

Second, a wide variety of organic compounds in natural waters and wastewater can act as complexing agents for metal ions. The nature and extent of metal ion complexation by natural water organics is not well-defined, probably because of the poorly defined nature of these organic compounds and also because of the staggering complexity of these... 

Compared to the number of compounds noted in the first edition of Comprehensive Heterocyclic Chemistry (CHEC-I), the field of rings larger than ten with one or more nitrogen heteroatoms has steadily developed and increased in importance. Most of these compounds were prepared in view of their use as complexing agents for metal ions, anions, or neutral organic molecules (host-guest complexes). 

Compared to chemically similar individual ligands, mac-rocyclic cyclophanes with several donor centers may be potent complexing agents for metal ions. Next to the chelate effect, this is often related to a productive preorganization of convergent donor functionality providing favorable coordination sites. 

Although non-ionic surfactants would appear to be unlikely candidates as complexing agents for metal ions, the interaction of some polyoxyethylene glycols with metal ions has recently attracted interest [90,91]. The reaction of non-cyclic polyoxyethylene derivatives with alkali and alkaline earth metals has been studied by means of solvent extraction of their thiocyanates or iodides. Polyoxyethylene dodecyl ethers with more than 7 ethylene oxide units were able to bind potassium ion in the water phase and to transfer the complexed salt to the organic phase the extracting power of Ci2Eg was about one sixth of that of a crown ether [92]. Some results are shown in Fig. 11.13. 

Complexing agent for metal salts, enhancing reactivity and solubility of the metal ion. Used as a complexing agent for Na and other alkali metals. Viscous liq. Misc. H2O. d4 1.10. Bpj g 115-116°. Hygroscopic. 

Complexing agent for metal salts. Complexes with KMn04 to form a benzene-soluble oxidant and with other polar reagents to increase solubility in nonpolar solvs. Used in extraction-separation of Hg, Ag as 1% soln. in dipentyl phthalate as ionophore in K-selective electrode. Colourless or pale yellow wax. Mp 38-54°. Bp 344°. 

Org. base with widespread uses, esp. manuf. of wet-strength resins and epoxy-resin curing agents. Complexing agent for metals. Used to treat Wilson s disease. Used as 0.5M aq. soln. of disulfate salt for photometric detn. of Cu(//) (/l x 9-11). Oil. 

Reactions of a-sulfonyloxynitriles with sulfur nucleophiles have not yet been described in the literature. As expected, sulfur nucleophiles react with O-activated cyanohydrins under Walden inversion to give the corresponding a-mercaptonitriles 31 and 32, respectively (Scheme 17) [62]. As illustrated in Scheme 17, optically active 2-amino thiols 34 are accessible from substitution products 32 by hydrogenation of the nitrile fimction. Compounds 34 could be of interest either as complexing agents for metal ions in catalysts or as starting compounds for chiral heterocycles (Scheme 17) [62]. 

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