Ethylenediaminetetra

STPP = sodium tripolyphosphate NTA = nitnlotriacetic acid EDTA = ethylenediaminetetraacetic acid EDTPO = ethylenediaminetetra(methylenephosphonic acid) (see Table 1). 

Multidentate ligands contain more than two coordinating atoms per molecule, e.g. 1,2-diaminoethanetetra-acetic acid (ethylenediaminetetra-acetic acid, EDTA),f which has two donor nitrogen atoms and four donor oxygen atoms in the molecule, can be hexadentate. 

The formation of a single complex species rather than the stepwise production of such species will clearly simplify complexometric titrations and facilitate the detection of end points. Schwarzenbach2 realised that the acetate ion is able to form acetato complexes of low stability with nearly all polyvalent cations, and that if this property could be reinforced by the chelate effect, then much stronger complexes would be formed by most metal cations. He found that the aminopolycarboxylic acids are excellent complexing agents the most important of these is 1,2-diaminoethanetetra-aceticacid (ethylenediaminetetra-acetic acid). The formula (I) is preferred to (II), since it has been shown from measurements of the dissociation constants that two hydrogen atoms are probably held in the form of zwitterions. The values of pK are respectively pK, = 2.0, pK2 = 2.7,... 

Crucibles fitted with permanent porous plates are cleaned by shaking out as much of the solid as possible, and then dissolving out the remainder of the solid with a suitable solvent. A hot 0.1 M solution of the tetrasodium salt of the ethylenediaminetetra-acetic acid is an excellent solvent for many of the precipitates [except metallic sulphides and hexacyanoferrates(III)] encountered in analysis. These include barium sulphate, calcium oxalate, calcium phosphate, calcium oxide, lead carbonate, lead iodate, lead oxalate, and ammonium magnesium phosphate. The crucible may either be completely immersed in the hot reagent or the latter may be drawn by suction through the crucible. 

Ethylenediaminetetra-acetic acid, largely as the disodium salt of EDTA, is a very important reagent for complex formation titrations and has become one of the most important reagents used in titrimetric analysis. Equivalence point detection by the use of metal-ion indicators has greatly enhanced its value in titrimetry. 

D. Alkalimetric titration. When a solution of disodium ethylenediaminetetra-acetate, Na2H2Y, is added to a solution containing metallic ions, complexes are formed with the liberation of two equivalents of hydrogen ion ... 

Ethylenediaminetetra-acetic acid (disodium salt see EDTA... 

Acetic add, ethylenediaminetetra-, 4,253 add-base equilibria, 2,779 in analysis, 1,522 complexes composition, 2,783 coordination numbers, 2,783 solid state structure, 2,783 cyclic derivatives complexes, 2,785 in electroplating, 6,14 heteroatom derivatives metal complexes, 2, 786 homologs... 

Earlandite structure, 6,849 Edge-coalesced icosahedra eleven-coordinate compounds, 1, 99 repulsion energy coefficients, 1,33,34 Edta — see Acetic acid, ethylenediaminetetra-Effective atomic number concept, 1,16 Effective bond length ratios non-bonding electron pairs, 1,37 Effective d-orbital set, 1,222 Egta — see Acetic acid,... 

When there is a limitation of the phosphorus content in detergents of 1%, then addition of phosphonates can act as an alternative solution in combination with other polyvalent ion-binding substances. Especially when magnesium is a cause of water hardness the zeoliths can form precipitations. But phosphonates, like hydroxyethanephosphonic acid (HEDP) and ethylenediaminetetra-methylenephosphonic acid (EDTMP), are able to sequester magnesium ions as well. 

Wilkinson SG (1968) Studies on the cell walls of pseudomonas species resistant to ethylenediaminetetra-ace-tic acid. J Gen Microbiol 54 195-213. 

Ru(bipy)3 formed in this reaction is reduced by the sacrificial electron donor sodium ethylenediaminetetra-acetic acid, EDTA. Cat is the colloidal catalyst. With platinum, the quantum yield of hydrogenation was 9.9 x 10 . The yield for C H hydrogenation was much lower. However, it could substantially be improv l by using a Pt colloid which was covered by palladium This example demonstrates that complex colloidal metal catalysts may have specific actions. Bimetalic alloys of high specific area often can prepared by radiolytic reduction of metal ions 3.44) Reactions of oxidizing radicals with colloidal metals have been investigated less thoroughly. OH radicals react with colloidal platinum to form a thin oxide layer which increases the optical absorbance in the UV and protects the colloid from further radical attack. Complexed halide atoms, such as Cl , Br, and I, also react... 

High-performance liquid chromatography (HPLC) with a micellar mobile phase or with a selective pre-column or reaction detection system has also been used to determine alkylenebis(dithiocarbamaes). ° Zineb and mancozeb residues in feed were determined by ion-pair HPLC with ultraviolet (UV) detection at 272 nm. These compounds were converted to water-soluble sodium salts with ethylenediaminetetra-acetic acid (EDTA) and sodium hydroxide. The extracts were ion-pair methylated with tetrabuthylammonium hydrogensulfate (ion-pair reagent) in a chloroform-hexane solvent mixture at pH 6.5-8.S. The use of an electrochemical detector has also been reported. ... 

Similar experiments were performed to measure the ET rate constants for the reaction between ZnPor in benzonitrile and aqueous reductants, Ru(CN)g, Mo(CN)g and FeEDTA (where EDTA denotes ethylenediaminetetra-acetic acid). Although the... 

Ethylenediaminetetra(methyl-enephosphonic acid) (EDTMP) concentration formation constants for metal chelates, 5 717t molecular formula, 5 713t Ethylenediaminodisuccinic acid, 19 265... 

Molar extinction coefficient,/ dm moP cm Ethylenediaminetetra-acetate tetra-anion EDTA -(acidisH EDTA Eig. 1.33)... 

The three most commonly used phosphonates are diethylenetriaminepenta (methylenephosphonic acid) (DTPMP), ethylenediaminetetra(methylenephospho-nic acid) (EDTMP), and hydroxyethyldiphosphonic acid or etidronic acid (HEDP) (Figure 10.3). DTPMP and EDTMP are also powerful chelants that complex strongly with most metal ions to form six-coordinate complexes, and for this reason are often... 

---