M. M. Ermilova

Palladium alloys as hydrogen permeable catalysts in hydrogenation and dehydrogenation reactions

Abstract The nature and the concentration of the second component of a binary palladium alloy affects its catalytic activity in hydrogen addition and subtraction reactions with organic compounds. Hydrogen permeation across a palladium alloy catalyst enhances the rate and selectivity of hydrogenation compared with what is observed when the compound being hydrogenated is mixed directly with hydrogen. The principal product of diene hydrogenation when the hydrogen permeates through a membrane catalyst is not a saturated hydrocarbon but the corresponding olefin from which polymers can be synthesized. The rate of hydrogen atom addition to the diene molecules on the palladium alloy surface is higher than the rate of hydrogen atom recombination and desorption in the form of hydrogen molecules.

Development and synthesis of bulk and membrane catalysts based on framework phosphates and molybdates

The scientific principles were formulated that underlie an integrated approach to development and synthesis of bulk and membrane catalysts for methanol transformation to dimethyl ether and hydrogen which are environmentally friendly fuels. The results were summarized for studies into relationships in formation of phosphates MZr2(PO4)3 (M = Na, K, Rb, Cs, Mg0.5, Ca0.5, Sr0.5, Ba0.5, Zr0.25), Cu0.5(1+y)FeyZr2−y(Po4)3, molybdate phosphates Na1−yZr2(Moo4)y(Po4)3−y, and molybdate Ni0.3Cr0.4Fe1.4(Moo4)3 with the desired structure and properties controllable by variation of their chemical composition and synthesis parameters. The surface characteristics and catalytic properties of the resulting systems and the yields of the target product formed from methanol transformations in inert and oxidizing atmospheres were analyzed in relation to the catalyst synthesis condition.

Catalytic properties of zirconium phosphate and double phosphates of zirconium and alkali metals with a NaZr2(PO4)3 structure

Zirconium orthophosphate Zr3(PO4)4 and double phosphates of zirconium and alkali metals AZr2(PO4)3 (A = Na, K, Rb, Cs) with a NaZr2(PO4)3 structure were synthesized and characterized by X-ray diffraction and electron microprobe analyses and capillary condensation of nitrogen. The catalytic properties of the phosphates in the dehydration of methanol were studied.

The new catalytic membranes with low sized phosphorus oxide structures on a surface

Abstract The molecular layering method was applied for obtaining of chromium-phosphorus oxide structures on a surface of stainless steel which used as a composite membrane catalyst. The structure and chemical content of composite were investigated by analytical method and by application of an electronic microscopy and ESCA. The catalytic properties of membranes were studied in a relation of methane oxidizing transformation at the temperature of 500–700 K. Formaldehyde was found as a main product of reaction.

Hydrogenolysis of propane on a palladium-ruthenium alloy membrane catalyst

Conclusions1.The rate of hydrogenolysis of propane and the selectivity for methane in delivery of hydrogen through a Pd-Ru alloy membrane catalyst is lower than in conducting the reaction in conditions of combined delivery of hydrogen and propane.2.In the 433–533 K temperature region corresponding to the coexistence of the α and β phases of palladium hydride, the rate of hydrogenolysis of propane does not increase with an increase in the temperature.

Hydrogenation of cyclopentadiene in the presence of isoprene and 1,3-pentadiene on a Pd-Ru membrane catalyst

Conclusions1.The hydrogenation of cyclopentadiene, containing up to 25% of isoprene and 1.5% of 1,3-pentadiene, on a membrane catalyst composed of Pd alloy containing 9.8% Ru, proceeds at the same rate and selectivity in cyclopentene as does pure cyclopentadiene.2.The relative adsorption coefficients of isoprene (0.6), 1,3-pentadiene (1.3), and cyclopentadiene (1) were determined.

Dehydration of butanols on copper-containing zirconium orthophosphates

The catalytic properties of ternary zirconium phosphates Na1-2x CuxZr2(Po4)3 in the transformations of butanols were been studied. It was found that the structure of alcohol and the copper content (x = 0, 0.15, 0.25, 0.35) affect the rate and selectivity of dehydration. The activity and selectivity changed as the content of copper that substitutes for sodium ions increased. The general conversion of alcohol and selectivity in dehydration decreased in the series butanol-2 →-isobutanol → butanol-1, due probably to the change in the apparent activation energy of the reaction, depending on the stability of alcohol binding to the surface.

Synthesis and catalytic properties of M0.5(1 + x)FexTi2 − x(PO4)3 (M = Co, Ni, Cu; 0 ≤ x ≤ 2) for methanol conversion reactions

New phosphates with the general formula M0.5(1 + x)FexTi2 − x(PO4)3 (M = Co, Ni, Cu; 0 ≤ x ≤ 2) have been synthesized by a sol-gel process. We have studied phase relations in these systems and determined the composition stability limits of NASICON-type solid solutions. The catalytic properties of the phosphates for methanol dehydration and dehydrogenation reactions have been investigated in an inert atmosphere.

Detonation nanodiamonds as catalysts of steam reforming of ethanol

Physicochemical properties and catalytic performance of detonation nanodiamonds were studied. Original samples of nanodiamonds and nanodiamonds modified by hydrogen, oxygen, and nitric acid with hydrogen peroxide and infrared-treated were investigated. The catalyst structure and morphology were examined by transmission electron microscopy and IR spectroscopy. All the investigated catalysts were active in the steam reforming of ethanol. The correlation of catalytic properties with composition and structure of the described systems is discussed. The specific surface area of nanodiamonds is changed insignificantly upon modification.

Effect of reaction products on dehydrogenation rate of isoamylenes on a membrane catalyst

The dehydrogenation of isoamylenes on a membrane catalyst composed of a Pd catalyst with 5.9% Ni under nongradient conditions is inhibited by isoprene, while the reaction rate passes through a maximum when the partial pressure of hydrogen in the starting mixture is increased.