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Metal-carbon nanocomposites are obtained as a result of mechanical activated dehydrochlorination of polyvinyl chloride in the presence of nickel nitrate and diethylamine with further carbonation of the isolated product. The resulting nanocomposites are distributed in the volume of an amorphous carbon matrix with nickel particles with a diameter of 50-100 nm. The Raman spectroscopy method confirms the formation of a carbon matrix from PVC. Heat treatment of samples at 400 ° C leads to the appearance of a line in the Raman spectra, which are characteristic of carbon structures. The formation of a metal-carbon nanocomposite was confirmed by transmission electron spectroscopy. [ABSTRACT FROM AUTHOR]

A series of MoO3/Al2O3 catalysts with a molybdenum oxide loading from 2 till 10 wt.% was prepared by incipient wetness impregnation of the support with a solution of molybdenum citrate complex. The use of citric acid in the impregnation solution during the preparation of MoO3/Al2O3 catalysts favoured the formation of highly dispersed molybdenum species. The degree of aggregation of molybdenum species in catalysts depended both on the molybdenum oxide loading and on the activation conditions. Samples containing mainly tetrahedrally coordinated molybdenum species in the form of surface monomolybdates according to UV-DRS data were active in the propylene metathesis. The catalyst loaded 7 wt.% MoO3 was the most active in the propylene metathesis reaction. It exhibited propylene conversion of 30% and a metathesis product selectivity of 96% at a temperature of 200 °C. [ABSTRACT FROM AUTHOR]

The influence of the preparation method and tungsten oxide content in the NiO/WO3/Al2O3 catalysts was studied. Optimal method of catalyst preparation is impregnation of support by solution of nickel precursor and then tungsten precursor. The maximum yield of propylene (15 %) is achieved over the WO3/NiO/Al2O3 catalyst with 7 wt. % WO3 at the temperature of 450 °C and weight hourly space velocity of 0.5 h-1. [ABSTRACT FROM AUTHOR]

During tests of palladium-rhenium catalysts based on sulfated zirconia in the process of direct synthesis of propylene from ethylene, it was found out that modifying the support with γ-Al2O3 increases significantly the stability of the system. Multi-cycle tests showed that systems with alumina content of 20 and 40 wt. % maintain its activity during a few tens of hours at the level of 50-80 %. The propylene yield from cycle to cycle remains practically unchanged (28-35 wt. %). According to UV spectroscopy and GLC with MSD, changes in the palladium and rhenium valence state don’t occur during the catalysts operation. The catalyst deactivation is caused by the C8+ oligomers deposit on its surface resulting from secondary processes of butenes oligomerization on the catalyst acid sites and C6+ hydrocarbons metathesis. [ABSTRACT FROM AUTHOR]

Metal-carbon nanocomposites are obtained as a result of mechanical activated dehydrochlorination of polyvinyl chloride in the presence of nickel nitrate and diethylamine with further carbonation of the isolated product. The resulting nanocomposites are distributed in the volume of an amorphous carbon matrix with nickel particles with a diameter of 50-100 nm. The Raman spectroscopy method confirms the formation of a carbon matrix from PVC. Heat treatment of samples at 400 ° C leads to the appearance of a line in the Raman spectra, which are characteristic of carbon structures. The formation of a metal-carbon nanocomposite was confirmed by transmission electron spectroscopy. [ABSTRACT FROM AUTHOR]