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Recognition of Environmentally Important Ions

Łukasik N., Wagner-Wysiecka E., Hubscher-Bruder V., Michel S., Bocheńska M.

Logistyka

2013

nr 4

The synthesis and binding properties of N,N’-bis(2-naphthyl)pyridine-2,6-dicarboxyamide are described. The ion binding ability in solution has been tested by UV-Vis spectrophotometry and liquid-liquid extraction of metal picrates from water into dichloromethane. Among studies ions spectral changes of ligand solution in acetonitrile were observed in the presence of Pb2+, Cu2+, and F- ions. The stability constants (logβ) and the stoichiometry of formed complexes were determined.

Artykuł przedstawia syntezę i właściwości kompleksujące receptora jonów, będącego amidową pochodną kwasu pirydyno-2,6-dikarboksylowego. Badania prowadzone były przy użyciu spektrofotometrii UV-Vis oraz metod ekstrakcyjnych.

Surface Structure and Catalytic Properties of Cu/SiO2 Catalysts Prepared by Different Methods

Ji D. H., Zou X. J., Zheng D. F., Wang L. X., Liu S. Y., Zhu W. C., Wang G. J., Wang Z. L.

Polish Journal of Chemistry

2008

Vol. 82, nr 5

1097-1104

The silica supported copper catalysts were prepared via impregnation (IM), solgel (SG) and deposition precipitation (DP) methods. The catalysts were characterized by XRD, H2-TPR, NH3-TPD, H2-N2O titration, XPS, BET and EPR techniques. The results indicated that two copper species, Cu2+ and Cu0 exist on the surface of SG catalyst; how ever, only Cu0 species could be found on the surface of reduced IM and DP catalysts, and the dispersion of Cu0 on IM catalyst was better than that on DP catalyst. According to the reaction results, Cu0 should be the active sites for dehydrogenation of cyclohexanol. Cu2+ species on the surface of SG catalyst might be responsible for the dehydration of cyclohexanol. The residual Na was found on the surface of DP catalyst, which made the acidity decreas ing, and the Cu crystallite growing up easily.

Study of Complex Formation Between 18-Crown-6 with Cu2+, Zn2+, Cd2+ and Pb2+ Cations in Some Binary Mixed Non-aqueous Solvents Using the Conductometric Method

Rounaghi G., Khazaee N., Sanavi K.

Polish Journal of Chemistry

2005

Vol. 79 / nr 7

1143-1153

The complexation reactions between Cu2+, Zn2+, Cd2+ and Pb2+ metal cations with 18-crown-6 (18C6) were studied in methanol (MeOH) - dimethylformamide (DMF) and ethylacetate (EtOAc) - dimethylformamide (DMF) binary mixtures at different temperatures using the conductometric method. The conductance data show that the stoichiometry of the complexes in all cases is 1:1 (ML). The values of thermodynamic parameters ( Hc 0, Sc 0) for 18C6-Cu2+, 18C6-Zn2+, 18C6-Cd2+ and 18C6-Pb2+ complexes in MeOH - DMF and EtOAc - DMF binary systems were obtained from temperature dependence of stability constants. The results show that the thermodynamics of complexation reactions is affected by the nature and composition of the mixed solvents and in most cases, the complexes are enthalpy stabilized but entropy destabilized. The stability constants Kf of all complexes increase with increasing the concentration of solvent with lower donicity (based on Gutmann donicity scale) in the binary mixed solvents. In most cases, a non-linear behaviour was observed for variation of logKf of the complexes with the composition of the mixed solvents. The selectivity order of 18C6 for these metal cations in all solvent systems used in this study is: Pb2+>Cd2+>Cu2+>Zn2+.