ADSORPTION DEFORMATION DURING LIQUID-PHASE HYDROGENATION OF UNSATURATED CARBON BONDS OVER BULK AND SUPPORTED NICKEL CATALYSTS

The regularity of changes in the particle size of nickel catalysts in the course of the hydrogenation process has been studied. The studies were carried out with a bulk nickel catalyst (skeletal nickel) and supported nickel catalysts (Ni/SiO2) with different quantity of active metal. A separate study of the overpressure effect on adsorption deformation during the catalytic reduction of the unsaturated bond "carbon-carbon" over bulk and supported nickel catalysts was carried out. It is shown that bulk catalysts, in contrast to supported ones, undergo the change in the average particle size as a result of local overheating caused by hydrogenation reactions, both at atmospheric pressure of hydrogen in the system and at overpressure. It was found that the overpressure of hydrogen, in contrast to atmospheric pressure, is capable of leading to a monodisperse distribution of skeletal nickel particles along the radius. It has been proven that it is the adsorption-catalytic deformation that leads to a monodisperse distribution of catalyst particles along the radius. The effect of adding sodium hydroxide in a solvent on residual aluminum in bulk nickel during the hydrogenation of sodium maleate has been studied. The kinetic parameters of the activity of skeletal and supported nickel catalysts in the reduction of the carbon-carbon double bond at atmospheric and overpressure have been established. It has been experimentally proven that the main reason that determines the effect from the nature and composition of the solvent to the catalytic properties of metal catalysts is the effect of the appearance of induced surface inhomogeneity. The experimental data obtained in this work suggest that pressure has a decisive effect on the effect of the solvent on the kinetics of sodium maleate hydrogenation. An increase in the hydrogen pressure in the system changes the character of the solvent effect on the activity of the nickel in the reactions under study.