Ethylenediaminetetraacetic acid stabilizer

The complexers maybe tartrate, ethylenediaminetetraacetic acid (EDTA), tetrakis(2-hydroxypropyl)ethylenediamine, nittilotriacetic acid (NTA), or some other strong chelate. Numerous proprietary stabilizers, eg, sulfur compounds, nitrogen heterocycles, and cyanides (qv) are used (2,44). These formulated baths differ ia deposition rate, ease of waste treatment, stabiHty, bath life, copper color and ductiHty, operating temperature, and component concentration. Most have been developed for specific processes all deposit nearly pure copper metal. 

In most systems, K2 < K[. Otherwise (e.g. the first two dissociation steps for ethylenediaminetetraacetic acid—EDTA) the first hydrogen ion capable of dissociation is stabilized by the presence of the second one and can dissociate only when the second begins to dissociate. As a result both hydrogen ions dissociate in one step. 

Table 1.8 Consecutive stability constants, expressed as logXMX., of complexes of ammonia (A), ethylene diamine (B), diethylenetriamine (C) and the anion of ethylenediaminetetraacetic acid (D4 ) at 20°C and 0.1 mKN03 as indifferent electrolyte. (According to J. Bjerrum and G.

Ferric citrate, molecular formula, 6 638t Ferric ethoxide, 14 533 Ferric ethylenediaminetetraacetic acid (ferric EDTA), 19 261 Ferric ferrocyanide, 8 186 22 810 pigment used in makeups, 7 836t Ferrichromes, 14 557 Ferric ion, acrylamide stabilizer, 1 289 Ferric nitrate bright pickle, 15 375 Ferric oxide... 

Uses Stabilizing rubber latex solvent for albumin, casein, shellac, and sulfur neutralizing oils in antifreeze as a corrosion inhibitor emulsifier adhesives textile lubricants fungicides manufacturing chelating agents such as EOT A (ethylenediaminetetraacetic acid) dimethylol-ethylene-urea resins organic synthesis. 

Ethylenediaminetetraacetic acid, analogs, complexes of, 3 277 chelation by, 3 276-277 cobalt complex of, 3 281 complexes, 3 277-278 formation constant of, 3 273-274 -nickel, 3 17-18 stability of, 3 266-267 reaction with metal ions, 3 62 Ethylene dibromide, irradiation of, 5 196 4,5-Ethylenedithio-1,3-dithiole-2-thione based supramolecular complexes, 46 200-204 Ethylene glycol, 32 4... 

Figure 10.11 Conditional stability constant graphs for (a) ethylenediaminedisuccinic acid [(S,S)-EDS], (b) ethylenediaminetetraacetic acid (EDTA), (c) iminodisuccinic acid (IDS), (d) glutamic acid N,N-diacetic acid (CLDA), and (e) methylglycinediacetic acid (MGDA).

From 1967 to 1969, Kerr published a series of papers on the question of thermal and hydrothermal stabilities of sodium and hydrogen zeolite Y (22-26). These studies indicated that upon removal of about one-third of the aluminum from zeolite Y, using ethylenediaminetetraacetic acid (H4EDTA), the thermal and hydrothermal stabilities were much enhanced. This was observed for both sodium (23) and hydrogen (25) forms of the zeolite. The latter was prepared by careful calcination of an ammonium zeolite from which about 30% of the ammonium and aluminum had been removed. Kerr also showed that the true or normal hydrogen zeolite with... 

For studies involving water, it may only be important to assure that the tracer remains fluid-bound. One can use tritium or almost any metal atom that can be complexed with EDTA (ethylenediaminetetraacetic acid) or DTPA (diethylene-triaminepeutacetic acid) (with a large stability constant). 

The base readily penetrates the hair and promotes bleaching. The addition of stabilizers such as sodium pyrophosphate or sodium oxalate [16,17] retards the decomposition of hydrogen peroxide in the alkaline preparation and thus enhances the bleaching action. The same holds for complexing agents (seques-trants) such as ethylenediaminetetraacetic acid, which hinder decomposition due to traces of heavy metals. Thickening additives include carboxymethyl celluloses, xanthine derivatives, and synthetic polymers. Certain dyes can also be added. 

The stability of some metal complexes is very large. For example, with ethylenediaminetetraacetic acid (EDTA,... 

Foreman, J. K., and Smith, T. D. The nature and stability of the complex ions formed by ter-, quadri-. and sexa-valent plutonium ions with ethylenediaminetetraacetic acid. Part I. pH titrations and ion exchange studies, J. Chem. Soc.,... 

Chelants at concentrations of 0.1% to 0.2% improve the oxidative stability through the complexation of the trace metal ions, e.g., iron, which catalyze the oxidative processes. Examples of the chelants commonly used are pentasodium diethyl-enetriaminepentaacetic acid (DTPA), tetrasodium ethylenediaminetetraacetic acid (EDTA), sodium etidronate (EHDP), and citric acid. Magnesium silicate, formed in wet soap through the reaction of magnesium and silicate ions, is another chelant commonly used in simple soap bars. 

Buffers can also be provided in parenteral formulations to ensure the required pH needed for solubility and/or stability considerations. Other excipients included in parenteral products are preservatives (e.g., benzyl alcohol, p-hydroxybenzoate esters, and phenol), antioxidants (e.g., ascorbic acid, sodium bisulfite, sodium metabisulfite, cysteine, and butyl hydroxy anisole), surfactants (e.g., polyoxyethylene sorbitan monooleate), and emulsifying agents (e.g., polysorbates). An inert gas (such as nitrogen) can also be used to enhance drug stability. Stability and solubility can also be enhanced by the addition of complexation and chelating agents such as the ethylenediaminetetraacetic acid salts. For a more detailed list of approved excipients in parenteral products, the reader should consult the monographs within the USP. 

Many dithiocarbamate complexes of zinc, silver, cadmium or mercury improve emulsion stability, including bis(dibenzyldithiocarbamato)-zinc(II) or -cadmium(II) and silver(I) diethyldi-thiocarbamate. Cadmium salts, mixed with citric acid or tartaric acid and added to the emulsion, are reported to be effective. Mercury(II) complexes of ethylenediaminetetraacetic acid (EDTA) and related ligands and of solubilized thiols such as (4) can be used. Other coordination compounds reported include EDTA and related ligand complexes of Co and Mn, mixtures of Co salts with penicillamine (5) and macrocyclic complexes of Ag such as (6). The latter compounds may be used in diffusion transfer systems in which transferred maximum densities are stabilized. 

Prompt stabilization of ascorbic acid is especially important in the case of plasma or serum samples. Metaphosphoric acid is often used for this purpose because it also serves as a protein precipitant. Such properties are desirable in the inactivation of oxidase and the catalytic eflFect of copper. Oxalic acid is an attractive stabilizer for ascorbic acid analysis because of its lower cost and greater stability however, it is not a protein precipitant, therefore, it has a limited use for the extraction of animal tissues. The use of ethylenediaminetetraacetic acid (EDTA) in addition to the metaphosphoric acid has been recommended (96). EDTA would chelate divalent cations, and a study has shown it will stabilize ascorbic acid in the presence of copper for several days (96). Perchloric acid has been used also but because of its inherent dangerous properties its use is generally avoided. Trichloroacetic acid and EDTA also seem appropriate extractants for ascorbate in plant materials (97). 

Stabilization of Foods. The oxidation of food containing fats and oils results in a loss of sensory appeal and eventually rancidness. FDA regulations covering the use of direct food additives are stringent and few new materials have been regulated. A number of products in use today, such as citric acid (33), and CC-tocopherol [59-02-9] (41), are in the GRAS list. The most commonly used materials are butylated hydroxytoluene [128-37-0] (1), -propyl gallate [129-79-9] (42), a-tocopherol, and butylated hydroxyanisole [25013-16-5] (43). The concentrations allowed in food are less than 0.02%. Metal deactivators such as citric acid (33), ethylenediaminetetraacetic acid (32) and its salts, and calcium chelate are used to deactivate transition metal oxidation catalysts. 

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