Adsorption properties of palladium particles supported on aluminum oxides with varied acidity in hydrogenation of butadiene-1,3

© 2017, Pleiades Publishing, Ltd.Influence exerted by acid-base modifiers of aluminum hydroxide on the texture and acid characteristics of the aluminum oxide support was studied. The effect of the modified aluminum oxides on the charge state of the active component of aluminum-palladium catalysts was determined. It was found that catalysts based on a support with high concentration of strong acid centers are characterized by low conversion of butadiene-1,3 due to the firm chemisorption of the diene on electron-deficient palladium particles. Their formation is due to the strong metal-support interaction. By contrast, catalysts synthesized with supports having a small number of acid centers provide a high conversion of butadiene-1,3

An Investigation of Surface Transformations of Nickel Highly Porous Cellular Material with an Applied Alumina Layer during Its Synthesis

© 2018, Pleiades Publishing, Ltd. For the development of a composite of nickel highly porous permeable cellular material with an applied secondary layer of alumina, transformation of the surface of the highly porous permeable cellular material is investigated at the stages of electrochemical synthesis and stages of alumina application on its surface. Etching of foamed-polyurethane bondings with 20% potassium hydroxide solution is accompanied by destruction of their surface and the formation of defective areas in the form of hillocks, hollows, and other imperfections acting as tin-hydroxide crystallization nuclei. Application of tin chloride with its subsequent hydrolysis leads to the formation of hemispherical tin-hydroxide grains with a mean size of about 80 nm uniformly distributed over the surface. The optimum values of temperature (50°C), solution pH (9–10), and electroless-nickel-plating duration (20–30 min), providing the formation of a conductive sublayer of chemically reduced nickel, are established. Nickel electroplating for 30 to 35 h at a current density of 0.1 A/dm2 yields high uniformity of a metal coating of foamed-polyurethane bondings across the thickness both in the bulk and at the outer periphery of a sample of 30 μm. A composite of nickel highly porous permeable cellular material with an applied alumina secondary layer is synthesized. The latter shows a high degree of uniformity and uniform thickness over the whole surface of bondings of the obtained composite

Fractional Quantum Mechanics

A path integral approach to quantum physics has been developed. Fractional path integrals over the paths of the L\'evy flights are defined. It is shown that if the fractality of the Brownian trajectories leads to standard quantum and statistical mechanics, then the fractality of the L\'evy paths leads to fractional quantum mechanics and fractional statistical mechanics. The fractional quantum and statistical mechanics have been developed via our fractional path integral approach. A fractional generalization of the Schr\"odinger equation has been found. A relationship between the energy and the momentum of the nonrelativistic quantum-mechanical particle has been established. The equation for the fractional plane wave function has been obtained. We have derived a free particle quantum-mechanical kernel using Fox's H function. A fractional generalization of the Heisenberg uncertainty relation has been established. Fractional statistical mechanics has been developed via the path integral approach. A fractional generalization of the motion equation for the density matrix has been found. The density matrix of a free particle has been expressed in terms of the Fox's H function. We also discuss the relationships between fractional and the well-known Feynman path integral approaches to quantum and statistical mechanics.Comment: 27 page

Selection of the optimum composition of an alumina support of Pd/Al 2O3 catalysts for pyrolysis gasoline hydrogenation

To optimize the chemical composition of catalysts for the selective hydrogenation of diene and vinyl aromatic hydrocarbons in pyrolysis gasoline, we study the effect of the acid-base and textural characteristics of a support modified with additives of sodium compounds on the activity and stability of the catalysts in reactions of hydrogenation and oligomerization of unsaturated compounds. It is shown that the rate of formation of oligomeric compounds depends on the number of Lewis (Q CO > 34 kJ/mol) and Brönsted sites (νOH = 3688 cm-1). An increase in their total amount on the catalyst surface leads to an increase in the rate of formation of oligomeric hydrocarbons. The amount of surface condensation products is determined by the concentration of strong aprotic sites with Q CO > 35 kJ/mol. Alumina support samples with a high surface concentration of medium-strong Lewis sites, wedge-shaped or conical pores, and the preferential distribution of porometric volume in pores with a diameter of 5-15 nm are characterized by a significant ability to oligomerize unsaturated compounds. Catalysts that contain 0.5 wt % Na exhibit the lowest oligomerization ability and a high stabile activity in reactions of hydrogenation of diene and vinyl aromatic hydrocarbons in pyrolysis gasoline. For the selective hydrogenation of diene and vinyl aromatic hydrocarbons in pyrolysis gasoline, we recommend a catalyst with 0.5 wt % Pd supported from palladium acetylacetonate on δ-Al2O3 modified with 0.5 wt % sodium; it is characterized by the absence of wedge-shaped or conical pores, the preferential (60.7%) distribution of porometric volume in a range of d p > 15 nm, and a low aprotic acidity (L = 3.1 μmol/g), which contributes to the decrease in the amount of resulting condensation products (V = 3.6 μg/(gcat h)) and a high stable activity (DN = 0.68 g J2/100 g) in reactions of hydrogenation of unsaturated compounds. © 2010 Pleiades Publishing, Ltd

Path Integral Approach to the Non-Relativistic Electron Charge Transfer

A path integral approach has been generalized for the non-relativistic electron charge transfer processes. The charge transfer - the capture of an electron by an ion passing another atom or more generally the problem of rearrangement collisions is formulated in terms of influence functionals. It has been shown that the electron charge transfer process can be treated either as electron transition problem or as elastic scattering of ion and atom in the some effective potential field. The first-order Born approximation for the electron charge transfer cross section has been reproduced to prove the adequacy of the path integral approach for this problem.Comment: 19 pages, 1 figure, to appear in Journal of Physics B: Atomic, Molecular & Optical, vol.34, 200

Pilot tests of a catalyst for the selective hydrogenation of acetylene

Pilot tests of SGA-2M promoted Pd/Al2O3 catalyst in the selective hydrogenation of acetylene are performed on an industrial ethane-ethylene fraction in a system of two serially arranged adiabatic flow reactors. The optimum process conditions under which the conversion of acetylene reaches 100% at a selectivity of 68.2% with respect to ethylene are determined: system pressure, 21 atm; hydrocarbon feedstock hourly space velocity (HSV), 1500 h-1, carbon monoxide concentration, 7 ppm; H2: C 2H2 molar ratio at the first and second hydrogenation stages, 1.0: 1.0 and 1.4: 1.0; inlet temperature of the first and second reactors, 40 and 55 C, respectively. The interregeneration service life of the SGA-2M catalyst under optimum conditions is estimated at 12 months. SGA-2M catalysts can be recommended for purifying ethane-ethylene fractions containing up to 2 vol % of acetylene. © 2013 Pleiades Publishing, Ltd

Angiomyofibroblastoma of the spermatic cord: a case report

<p>Abstract</p> <p>Introduction</p> <p>Angiomyofibroblastoma is a benign soft tissue tumor with tendency to arise in the vulva.</p> <p>Case presentation</p> <p>We report a 36-year-old Greek Caucasian man presenting with a left inguinal painless mass. This is the second case of angiomyofibroblastoma of the spermatic cord. At operation, a 4.5 cm well-circumscribed solid tumor was found adherent to the spermatic cord. The tumor consisted of spindle-shaped cells proliferating in short fascicles between numerous medium-sized blood vessels with thin and hyalinized walls. Neoplastic cells had eosinophilic cytoplasm with neither mitotic figures nor nuclear atypia. The stroma included abundant mast cells and few mature lypocytes. Immunostaining showed positivity for vimentin, CD34, desmin and smooth muscle actin. Our patient was treated by simple excision and was followed up for five years with clinical examination and ultrasonography, revealing no evidence of local recurrence or metastasis.</p> <p>Conclusion</p> <p>This unusual neoplasm should be distinguished from aggressive angiomyxoma and other myxoid malignant tumors with widespread metastatic potential.</p

Numerical simulation of the thermal fragmentation process in fullerene C60

The processes of defect formation and annealing in fullerene C60 at T=(4000-6000)K are studied by the molecular dynamics technique with a tight-binding potential. The cluster lifetime until fragmentation due to the loss of a C2 dimer has been calculated as a function of temperature. The activation energy and the frequency factor in the Arrhenius equation for the fragmentation rate have been found to be Ea = (9.2 +- 0.4) eV and A = (8 +- 1)10^{19} 1/s. It is shown that fragmentation can occur after the C60 cluster loses its spherical shape. This fact must be taken into account in theoretical calculations of Ea.Comment: 12 pages, 3 figure

The influence of the structural and electronic characteristics of palladium on the activity and selectivity of Pd/Al 2O 3 and Pd-Co/Al 2O 3 catalysts for the hydrogenation of acetylene hydrocarbons

The influence of the structural and electronic characteristics of nonpromoted and cobalt-promoted Pd catalysts on their adsorption and catalytic properties is studied. It is shown that the conversion of vinylacetylene depends on the dispersion of palladium for both types of catalysts synthesized from acetate and acetylacetonate complexes. The palladium acetylacetonate catalysts have a higher palladium dispersion than the samples obtained from acetate complex solutions, thus leading to a higher conversion of vinylacetylene. It is established that the selectivity of vinylacetylene conversion into 1,3-butadiene on palladium acetate and acetylacetonate catalysts depends on the state of the 3d orbitals of surface Pd atoms. The palladium acetate catalysts are characterized by a higher electron density on the 3d orbital in comparison with the acetylacetonate samples, thus producing higher selectivities of vinylacetylene conversion into 1,3-butadiene. The introduction of cobalt into Pd/δ-Al 2O 3 catalyst synthesized from acetylacetonate complex leads to the formation of bimetallic Pd-Co particles, in which Pd atoms have higher electron density than those in the nonpromoted Pd/δ-Al 2O 3 catalyst, due probably to the donation of electron density from promoter atoms, with a resulting decline in the adsorption ability of bimetallic particles with regard to 1,3-butadiene and hydrogen. As a consequence, the selectivity of vinylacetylene conversion into 1,3-butadiene increases. Requirements for the size, dispersion, and electronic characteristics of the active component in the catalysts for the selective hydrogenation of vinylacetylene are formulated, and two techniques for their synthesis are proposed. © 2011 Pleiades Publishing, Ltd

Fractional Dynamics from Einstein Gravity, General Solutions, and Black Holes

We study the fractional gravity for spacetimes with non-integer dimensions. Our constructions are based on a geometric formalism with the fractional Caputo derivative and integral calculus adapted to nonolonomic distributions. This allows us to define a fractional spacetime geometry with fundamental geometric/physical objects and a generalized tensor calculus all being similar to respective integer dimension constructions. Such models of fractional gravity mimic the Einstein gravity theory and various Lagrange-Finsler and Hamilton-Cartan generalizations in nonholonomic variables. The approach suggests a number of new implications for gravity and matter field theories with singular, stochastic, kinetic, fractal, memory etc processes. We prove that the fractional gravitational field equations can be integrated in very general forms following the anholonomic deformation method for constructing exact solutions. Finally, we study some examples of fractional black hole solutions, fractional ellipsoid gravitational configurations and imbedding of such objects in fractional solitonic backgrounds.Comment: latex2e, 11pt, 40 pages with table of conten