Efficiency of using heteropoly compounds of the type (NH4)2[Co(H2O)4]2[Mo8O27]∙6H2O as catalysts for the production of ethylene

Carrying out heterogeneous acid catalysis with the use of heteropoly compounds has received considerable attention due to the great economic and environmental benefits. In spite of this, its industrial application is limited as there are difficulties in catalyst regeneration (settling) caused by its relatively low thermal stability. The aim of present work was to search and select catalysts related to the class of heteropoly compounds for propane cracking, to test the selectivity of the prosses as well as to discuss possible approaches for solving the problem of catalyst deactivation, that can contribute to achieve stable characteristics of solid heteropoly catalysts. Among these approaches are: the development of new catalysts with high thermal stability, the modification of catalysts to promote coke combustion, the inhibition of coke formation on heteropoly compound catalysts during the process, carrying out the reactions in supercritical media and also the cascade reactions using a multifunctional heteropoly catalyst. The obtained catalyst was also studied by physicochemical methods to get deep knowledge about which features of these compounds influence on the catalytic activity. A highly active and selective catalyst for ammonium octomolybdenocobaltate(II) ammonium (NH4)2[Co(H2O)4]2[Mo8O27]∙6H2O was synthesized for cracking associated petroleum gases. The qualitative, quantitative, and structural composition as well as the specific surface area of the obtained catalyst was established by the methods of X-ray diffraction, X-ray phase and fluorescence analysis. It was revealed that ammonium octomolybdenocobaltate(II) crystallizes in a triclinic syngony with cell parameters: а = 8.6292(9) Å b = 9.4795(10) Å c = 12.2071(13) Å α = 104.326(2)° β = 109.910(2)° γ = 100.820(2)°.

INORGANIC PIGMENTS BASED ON HETEROPOLY COMPOUNDS FOR PROTECTIVE-DECORATIVE ALUMINOPHOSPHATE -BONDED COATINGS

Inorganic pigments are synthesized in the paper. These inorganic pigments contain molybdophosphates and molybdosilicates of transition metals as chromophores, and dispersed silicates with different structural groups of silicon-oxygen tetrahedra, in particular marshalite and wollastonite, as substrates. The inorganic pigments obtained are brightly colored, highly light-stable and acid-resistant. The color of the pigments depends on the transition metal used during the synthesis process, as well as on the acid medium. The paper demonstrates the possibility of using inorganic pigments based on heteropoly compounds for protective-decorative and fire-resistant aluminophosphate-bonded coatings. X-ray diffraction (DRON-UM1 diffractometer, filtered Co Kα radiation) and IR spectroscopy (Nicolet 5700 FTIR spectrometer) show that the phases of AlPO4, Al(PO3)3 and Al(H2PO4)3, quartz (wollastonite), and pigment are contained in the alumophosphate-bonded coating. A small amount of the phase Al3(OH)3(PO4)2·H2O is detected. Thermal analysis performed using the SDTQ600 thermal analyzer shows that the structure of protective-decorative coatings is preserved at the temperatures of about 900 °C, which allows these pigments to be used for the manufacture of heat-resistant ink compounds. Optical studies (Axiovert 200M) confirms that after thermal treatment the colored coatings have a homogeneous structure that does not contain cracks and can, therefore, be used for coating both metal and concrete surfaces.