Ethylenediamine Uses

Chelating agents can coordinate with metal ions at a minimum of two sites. Typically this bidentate coordination solubilizes or otherwise inactivates these metal ions. The effect is to counter any deleterious actions these metals might have on the system in which the chelates are used. The chelating agents form ring structures that incorporate the metal ion within the molecule250. 

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Reaction of Ethylenediamine. Using 0.015 mole of diamine, 0.9 gram (61%) of bisacetylacetoneethylenediiminocopper(II) was obtained. Red platelets, m.p. 138-41° (dilute ethanol). There was no depression of melting point on admixture with authentic sample. Using 0.005 or 0.01 mole of amine, a mixture of blue and gray crystals was obtained, suggesting hydrolysis and, certainly, the absence of amine exchange. 

According to W. E. Bachmann et al. [19] the second of these methods gives a better yield (87% calculated in relation to the ethylenediamine used). 

The phenomenon was observed for the first time by Brdicka [13] in the reduction of riboflavin and methylene blue studied by d.c. polaro-graphy. It did not receive much attention until it was rediscovered by several workers studying systems such as Tl+/Tl(Hg), Pb2+/Pb(Hg), and the more obvious system Co(III)—Co(II)—tris-ethylenediamine using impedance measurements [14—16]. The confusion that arose initially in the literature around this subject in the end led to the correct theoretical description [15, 17, 18], the general treatment remaining very complex [18,19]. 

Rate studies of the reaction between cesium and water in ethylenediamine, using the stopped-flow technique, have been extended to all alkali metals. The earlier rate constant (k — 20 NT1 sec.-1) and, in some cases, a slower second-order process (k — 7 Af"1 sec.-1) have been observed. This is consistent with optical absorption data and agrees with recent results obtained in aqueous pulsed-radiolysis systems. Preliminary studies of the reaction rate of the solvated electron in ethylenediamine with other electron acceptors have been made. The rate constant for the reaction with ethylene-diammonium ions is about 105 NCl sec.-1 Reactions with methanol and with ethanol show rates similar to those with water. In addition, however, the presence of a strongly absorbing intermediate is indicated, which warrants more detailed examination. 

All the solvents were purified by standard methods[10]. 2,5-dihydroxyterephthalaldehyde (dhtH2) was prepared from dimethylhydroquinone ether using the literature methods[ll]. Polymeric Schiff base ligand P-dhtenH2, [Poly(2,5-dihyeroxyterephthalaldehyde ethylenediamine diprotonated)] was prepared by condensation of 2,5-dihydroxyterephthalaldehyde with ethylenediamine using the reported procedure with some modifications[12]. Infrared spectra were recorded on a Bruker IPS 66V FT-IR and thermal analysis on Delta series TGA-7. 

Polymer Syntheses. The block copolyether-urethane-ureas were synthesized from polypropylene glycol, methylene bis(4-phenylisocyanate), and ethylenediamine using a two-step solution polymerization (7). The repeat unit structure was ... 

Materials. The copolyether-urethane-ureas were prepared from polypropylene glycol, methylene bis(4-phenylisocyanate), and ethylenediamine using a modified solution polymerization technique (7). The polypropylene glycols used had molecular weights of 700, 1000, and 2000 the resulting copolymers were coded PEUU 700, PEUU 1000, and PEUU 2000. Inherent viscosities in N,iV-dimethyl-formamide at 30°C and 0.5% concentrations were 0.47, 0.65, and 0.50, respectively. 

Figure 4.10. Simple check of completeness of reaction between sample matenal and colorforming reagent, as demonstrated on the reaction between nitrite [1 ppm in (a) and 1.5 ppm in (b)] and N-(l-naphthyl)ethylenediamine using manifold Fig. 4.9a. To test the effect of longer residence times, the sample zone was stopped 9 s after injection in the coil for periods of 30-180 s, whereupon the pump was reactivated, the peaks being recorded repeatedly from the same start (5), (a). For shorter residence times (b) the signal was recorded continuously (Go) as well as when the sample zone 15 s after injection was stopped within the. flow cell (Stop). The sample volume in all experiments was identical (30 xL).

Acrylate, Ammonia, and Ethylenediamine Using Various Reaction Sequences. 383 Polymerizations in Supercritical Fluids. 386... 

The kinetics of the reaction of [Co2(Et2dtc)s]BF4 with some N-substituted ethylenediamines using CH2CI2 as solvent have also been studied. As with the dithio-oxamides these reactions appear to involve a preequilibrium dissociation (Scheme 3) followed by rate-determining attack by the ligand or solvent on the intermediate. 

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