Origin of the Pd-Rich Pentlandite in the Massive Sulfide Ores of the Talnakh Deposit, Norilsk Region, Russia

Pd-rich pentlandite (PdPn) along with ore-forming pentlandite (Pn) occurs in the cubanite and chalcopyrite massive sulfide ores in the EM-7 well of the Southern-2 ore body of the Talnakh deposit. PdPn forms groups of small grains and comprises marginal areas in large crystals of Pn. The palladium content in PdPn reaches up to 11.26 wt.%. EDS elemental mapping and a contour map of palladium concentrations indicate distinct variations in the palladium content within and between individual grains. Palladium distribution in the large grains is uneven and non-zoned. PdPn was formed as the result of a superimposed process, which is not associated with either the sulfide liquid crystallization or the subsolidus transformations of sulfides. Deming regression calculations demonstrated the isomorphic substitution character of Ni by 0.71 Pd and 0.30 Fe (apfu), leading to PdPn occurrence. The replacement of Ni by Fe may also indicate a change in sulfur fugacity, compared to that taking place during the crystallization of the primary Pn. The transformation of Pn into PdPn could have occurred under the influence of a Pd-bearing fluid, which separated from the crystallizing body of the massive sulfide ores.

Ionic Liquids/SiO2 Supporting Pd Nanoparticles: Efficient Catalysts in Hydrogenation Reaction

Palladium nanoparticles (ca. 4.8 nm) were synthesized in presence of 1-n-butyl-3-methylimidazolium tetraflouroborate (BMI.BF4) and 1-n-butyl-3-methylimidazolium hexafluorophosphate (BMI.PF6) and PMI.Si.(OMe)3.Cl functionalized ionic liquids using the sol-gel method. The characteristics of the sol-gel method, ionic liquid on the palladium content was studied, as well as the silica morphology and texture of the support and the hydrogenation activity. The palladium content in the resulting xerogels (ca. 0.22 wt% Pd/SiO2) was shown to be independent of the sol-gel process. The xerogels synthesized in acidic conditions formed materials with larger pore diameters, which in turn might be responsible for the higher catalytic activity in hydrogenation of the alkenes and arenes obtained with the heterogeneous catalyst (Pd/ILs/SiO2).

Simple, Sensitive, and Easy to use Method for Determination of Palladium Content in Palladium Acetate Using Flame Atomic Absorption Spectrophotometry

A simple, sensitive, and easy to use method for the determination of palladium content in palladium acetate was developed using homogeneous acid digestion of palladium acetate followed by atomic absorption spectrometry (AAS) analysis. Parameters affecting the extraction efficiency of palladium during digestion of palladium acetate were investigated and optimized. The palladium content was measured at 244.7 nm by atomic absorption (AA) spectrometers on PinAAcle™ 900 series with an air-acetylene flame. The linear calibration graph was observed in the range of 2.5-15 ppm with a limit of detection of 8.33 ppm and a correlation coefficient of 0.999970. For 5 replicate analyses of each palladium reference solution the relative standard deviation was within 2.00%.Analytical method validation for the method was carried out and obtained results were satisfactory.To verify, the accuracy parameter of the method validation, for the determination of Pd(II) from sample palladium acetate standard addition method was applied and satisfactory results were obtained. Optimization of analytical method variables during analytical method development is discussed.

ASSAY AND GRAPHITE FURNACE- ATOMIC ABSORBANCE SPECTROMETRY ACCURACY FOR PALLADIUM CONTENT ANALYSIS

Palladium is a member of the expensive Platinum Group Metals as it is indispensable for various applications of modern technology. Due to the very small number of these elements in nature, high-sensitivity analytical methods and devices are required for accurate PGM measurement. The current study aims to determine the accuracy level of the Graphite Furnace-Atomic Absorbance Spectrometry device for palladium analysis after pre-concentration through the assaying process. The studied samples were two in-house standard reference samples with stream sediment and ultramafic rock matrices. Due to the lack of certified reference material containing certain palladium compositions, the degree of accuracy was tested by the spiking method. The detection limit for Pd in this study was 11.79 ppb. Pd content in the stream sediment (17 ppb) is much lower than of the ultramafic sample (290 ppb), implying PGM association to ultramafic rock naturally. Almost all measurements have good accuracy according to spike recovery between 80-120%. Inaccurate addition process and inappropriate calibration range most probably lead to inaccuracy.

Linear Hexane Isomerization Over Bimetallic Zeolite Catalysts

The aim of this study was to evaluate the activity and selectivity in isomerization of n-hexane of bimetallic zeolite catalysts containing a nickel transition metal in addition to palladium. Bimetallic bifunctional linear alkane isomerization catalysts based on the hydrogen form of MFI zeolite have been synthesized. The porous properties of the samples were investigated by means of low-temperature nitrogen adsorption/desorption, the size of the metal component – by TEM, and the catalytic properties – in the micro-pulse isomerization of n-hexane. Antisymbatic correlation between the temperature of the maximum yield of hexane isomers and the amount of nickel in the sample was found for a stable palladium content. The introduction of nickel allows to reduce the optimum process temperature from 598 to 523 K.

Determination of elemental impurities of Arsenic, Cadmium, Mercury, Lead and Palladium content in Testosterone propionate by using ICP-MS

The aim of the present work is to develop and establish a validated analytical method for the determination of arsenic, cadmium, mercury, lead and palladium content in testosterone propionate by using inductive coupled plasma mass spectroscopy (ICP-MS). Samples were analyzed after a preparation of sample solution by dissolving in suitable solvents of concentrated nitric acid and concentrated hydrochloric acid. In the present method, RF power of 1550 watts, RF matching is 1.80 V, nebulizer flow of 0.10 rps and plasma view at spectrum mode were used. Octopole conditions are He flow is on, He flow rate is 4.3 mL/min and energy discrimination is 3.0 V were used. Significant savings in sample volumes, reagents, analysis cost and time are realized. Arsenic, cadmium, mercury, lead and palladium are primary concerned due to their high toxicity and potential contaminants should be limited in testosterone propionate and the developed method was validated according to ICH and USP guidelines. The correlation coefficient, recovery rate, LOD and LOQ reached the acceptable limits. The validated method was selective, sensitive, rapid and capable of the determination of elemental impurities of arsenic, cadmium, mercury, lead and palladium content in bulk drugs.

On the Amine-Catalyzed Suzuki-Miyaura Coupling Using a Catalysis-Based Fluorometric Method

<p>The Suzuki-Miyaura coupling is one of the most frequently used reactions in organic synthesis. Recent work by others suggested that an arylamine, prepared by palladium catalysis and tricyclohexylphosphine, could catalyze Suzuki-Miyaura coupling reactions without transition metals. Herein, we used a fluorometric quantification method for palladium previously developed in our laboratory to unambiguously conclude that there is a correlation between the palladium content in the arylamine and the rate of a Suzuki-Miyaura coupling. Also, our mass spectroscopic analysis of the arylamine revealed the presence of a palladium-phosphine complex. When Pd(OAc)₂ was used as a catalyst for the same Suzuki-Miyaura coupling, tricyclohexylphosphine was detrimental to the coupling and that the arylamine played negligible role. This study demonstrates the utility of the fluorometric technology for catalysis research.<br></p>

On the Amine-Catalyzed Suzuki-Miyaura Coupling Using a Catalysis-Based Fluorometric Method

<p>The Suzuki-Miyaura coupling is one of the most frequently used reactions in organic synthesis. Recent work by others suggested that an arylamine, prepared by palladium catalysis, could catalyze Suzuki-Miyaura coupling reactions without transition metals. Herein, we used a fluorometric quantification method for palladium previously developed in our laboratory to unambiguously conclude that there is a correlation between the palladium content in the arylamine and the rate of a Suzuki-Miyaura coupling. Also, our mass spectroscopic analysis of the arylamine revealed the presence of a palladium-phosphine complex. We discovered that the phosphine was detrimental to the palladium catalysis and that the arylamine played negligible role. This study demonstrates the utility of the fluorometric technology for catalysis research.</p>

On the Amine-Catalyzed Suzuki-Miyaura Coupling Using a Catalysis-Based Fluorometric Method

<p>The Suzuki-Miyaura coupling is one of the most frequently used reactions in organic synthesis. Recent work by others suggested that an arylamine, prepared by palladium catalysis, could catalyze Suzuki-Miyaura coupling reactions without transition metals. Herein, we used a fluorometric quantification method for palladium previously developed in our laboratory to unambiguously conclude that there is a correlation between the palladium content in the arylamine and the rate of a Suzuki-Miyaura coupling. Also, our mass spectroscopic analysis of the arylamine revealed the presence of a palladium-phosphine complex. We discovered that the phosphine was detrimental to the palladium catalysis and that the arylamine played negligible role. This study demonstrates the utility of the fluorometric technology for catalysis research.</p>