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Dibenzopyridino-18-crown-6 as a highly selective and effective carrier for uphill transport of Pb2+ through a bulk liquid membrane

Zolgharnein J., Hosseini S., Sangi M. R., Dadfarnia S., Shamsipur M.

Chemia Analityczna

2003

Vol. 48, No. 1

65-75

A chloroform membrane containing a dibenzopyridino-18-crown-6 carrier was found to be an excellent system for the uphill transport of Pb(2+). For P(2+)O4-(7), as a suitable metal cation acceptor in the receiving phase, and picrate, as a counter anion in the source phase, this system can selectively and efficiently transport Pb(2+) from aqueous solutions containing Pb(2+) and interfering cations, such as Ni(2+), Ca(2+), Hg+, Fe(3+), Zn(2+), Cd(2+) and Hg(2+). The amount of Pb(2+) transported across the liquid membrane after 2 h is (96.0š1.2)%.

Chloroformowa membrana zawierająca dibenzopirydyno-18-koronę-6 jako nośnik okazała się doskonałym układem w transporcie jonów ołowiu. Stosując pirofosforan, P(2)O4-(7), jako dogodny akceptor jonów metalu w fazie otrzymującej, a jon pikrynianowy, jako przeciwjon w fazie wyjściowej, uzyskuje się selektywny, działający z dobrą wydajnością efektywny transport jonów ołowiu z roztworów wodnych zawierających takie potencjalnie interferujące jony, jak Ni(2+), Ca(2+), Ag(+), Fe(3+), Zn(2+), Cd2+ and Hg2*. Ilość ołowiu transportowana przez ciekłą membranę wynosi po 2 godz. (96.0š1.2)%.

Kinetics and Mechanism of Oxidative transformations of (6R)-6-(A-Phenyl-D-glycylamino)penicillanic Acid (Ampicillin) by Manganese(III) in Pyrophosphate Medium

Subrahmanyam E., Ishwar Bhat K., Sherigara B., Satyanarayana D.

Polish Journal of Chemistry

2000

Vol. 74, nr 6

793-800

Manganese(III) has been stabilized in weakly acidic solution by pyrophosphate and the compklex Formed was elucidated spectrophotoetrically. Stoichiometry of magnese (III) oxidation of apicillin in pyrophosphate medium was establishesd in the pH range 2.0-3.0 by iodometric and spectrophotometric methods.The oxidation follows first order kinetics in [Mn(III)]. The effect of varying [Mn(III)], [Amp], [H+], added [Mn(II)], total[P2O7 4-] and added[ClO-4],[SO4 2-] ions have been studied. The order in [Amp] is unity and increase in [H=] increases the rate. With increase in [Mn(II)] and [P2O4- 7], a retardation effect was noticed. Oxidation products have been proposed. Dependence of reaction rate on temperature has been studied and activation parameters were computed. A mechanism consistent with the observed results has been proposed.