RESEARCH OF ACID PROPERTIES OF COMPLEX OXIDE CATALYST 50%Cu3(PO4)2•50%Ni3(PO4)2

Abstract

Individual orthophosphates of copper (II) and nickel (II) were synthesized and a new method of synthesis was developed, and a new complex catalytic system based on them of the type xCu3(PO4)2×yNi3(PO4)2 - 50%Cu3(PO4)2∙50%Ni3(PO4)2 was obtained, which has the predicted optimal acidic surface properties and the corresponding active centers. The acidic properties of the surface of the obtained individual copper (II) and nickel (II) phosphates and complex copper-nickel phosphate catalytic systems and the distribution of active centers on them were investigated. The peculiarities of the influence of synthesis conditions and temperature on the composition, structure and acidic properties of the surface of the obtained catalysts, as well as the nature and character of the formation of active centers of different strengths, were studied. It is established that calcination of the new synthesized copper-nickel phosphate catalytic system in the studied temperature range (120-700оС) allows not only to carry out complete dehydration of the obtained crystalline hydrate, but also contributes to a gradual change in the value of surface acidity. This leads to the formation on the surface of the synthesized complex copper-nickel phosphate catalytic system 50%Cu3(PO4)2∙50%Ni3(PO4)2 acidic active centers of appropriate strength. The promoting role of nickel ions Nі2+ in the structure of the copper-phosphate catalyst was confirmed and the presence of a synergistic effect of both these phosphates on the value of acidity in the structure of the synthesized complex catalytic system was established. A new active and cheap acidic complex catalyst – 50%Cu3(PO4)2∙50%Ni3(PO4)2, which has the necessary structure, optimal acidic surface properties, and appropriate active centers, has been obtained; therefore, it can be used for research in the chemical industry as an active and efficient catalyst for the partial oxidation of hydrocarbons into valuable products.
 Keywords: catalysts; heterogeneous catalysis; phosphates; complex oxides; oxidation; n-alkanes; hydrocarbons; ethane; ethylene.