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oxidation of methane at low temperature have been extensively studied so far [ 9 – 14 ]. In particular, palladium-based systems have been widely reported in literature as the catalyst of choice in methane combustion [ 15 , 16 ]. Some properties of these
silver, gold, and palladium nanoparticles on the surface of such hydride silicas was studied [ 7 , 12 – 15 ]. Direct reduction of ions on the hydride silica surface allowed us to control the sizes of formed metal particles within certain limits by
Abstract
The sorption of Pd(II) on hydroxyapatite (Ca10(PO4)6(OH)2) has been studied at 25 °C as a function of pH, in 0.01 M NaClO4, and 0.01 and 0.025 M Ca(ClO4)2 aqueous background electrolytes and Pd(II) concentration (9.3 to 47 μM), trying to minimize some types of reactions, such as solid dissolution of and metal precipitation. The radiotracer palladium, 109Pd, obtained by neutron irradiation, has been used to calculate the palladium’s distribution coefficients K d between aqueous and solid phase. A mathematical treatment of results has been made by ion-exchange theory in order to interpret palladium sorption onto treated solid. For this, we take into account the existence of active sites at the hydroxyapatite surface, and the aqueous solution chemistry of palladium as well as the effect of phosphate anions from solid dissolution. The results can be explained as evidence of sorption of the species PdOH+, and of a mixed hydroxo complex of Pd2+ like (XCaO−)–PdOH+·nH2O fixed onto {≡Ca–OH} surface sites of the hydroxyapatite.
Thermal behaviour and electro-optical properties of a series of liquid crystals based on palladium complexes with mixed ligands
Schiff bases and N-benzoyl thioureas
examples where the unique properties of anisotropic fluids are combined with the specific properties of metals, such as colour, polarizability, electrical and magnetic properties. Organometallic compounds of palladium based on ortho -metallated complexes
Abstract
Aiming the selective recovery of palladium from high level radioactive liquid waste (HLW), a chelating thiamide type sorbent, CWP–TU, was prepared by the modification of Japanese cedar wood powder (CWP). Convection oven and microwave heating were separately used for modification purpose and found that microwave heating is more effective over oven heating. CWP–TU was extensively studied for the adsorption of Pd(II) from nitric acid medium. The batch test showed that nitric acid concentration of 3 M or higher is favorable for Pd(II) loading. Consistent adsorption of Pd(II) under gamma irradiation condition demonstrated the feasibility of using CWP–TU in real HLW. Also, Pd(II) only adsorption from simulated HLW solution verified the palladium only selectivity of the sorbent as well as the lack of influence of coexisting metal ions on its affinity toward Pd(II). CWP–TU holds maximum Pd(II) loading capacities of 0.98 mol/kg at 30 °C and 1.04 mol/kg under gamma irradiation. A comparative study using some ion exchange resins revealed that the resins are either ineffective in nitrate medium or lack stability under irradiation.
Abstract
Palladium complexation in concentrated nitric acid solutions was studied by UV/Vis absorption spectrophotometry. The ionic strength of the solutions was fixed to I = 1, 3, or 5 mol dm−3 (M) by mixing of HNO3 and HClO4. The major palladium species were found to be Pd2+, PdNO3 +, and Pd(NO3)2. The formation constant of PdNO3 + was determined to be β 1 = 1.32 (I = 1 M), 1.49 (I = 3 M), or 1.47 (I = 5 M), while that of Pd(NO3)2 to be β 2 = 0.45 (I = 3 M) or 0.14 (I = 5 M).
Abstract
A cellulose xanthate supported palladium(0) complex was synthesized using a simple method and characterized by XPS, TG/DTA etc. The complex has good thermal stability from room temperature to 250 °C and it was found to be an efficient catalyst for the Heck reaction of acrylic acid or styrene with aryl iodide at low temperature under atmospheric pressure, and the substituted trans-cinnamic acid or 1, 2-stilbene was obtained with high yield at 90 °C. The reaction duration is about 8 h. The cellulose xanthate supported palladium(0) complex could be separated from the reaction mixture easily and reused for several cycles. The yield of the product was up to 55.3% when the catalyst was run for 10 times. The active center in the complex is Pd metal.
Introduction Palladium supported carbon materials (activated carbon, carbon fibres, carbon black, nanotubes) are highly suitable catalysts for several chemical and electrochemical reactions [ 1 – 13 ]. Relevant concerns
New palladium(II) complexes with pyrazole ligands
Part I. Synthesis, spectral and thermal studies, and antitumor evaluation
νNN band to higher frequencies (Δν ≅ 60–125 cm −1 ) compared to that of the free ligands indicates a strengthening of the N–N bond as a result of the interaction between palladium(II) and pyridine-like nitrogen atom [ 31 ]. The ν as SCN vibration for
Abstract
Various (±)-trans-2-arylnitrocyclohexane derivatives were hydrogenated to the corresponding amines over a Pd/C catalyst in methanol at 25–60 °C and 1–12 bar. These (±)-trans-2-arylcyclohexylamines are important and valuable key intermediates for the stereoselective synthesis of phenantridine-based Amaryllidaceae alkaloid analogues having cytostatic activity.
