from first principles PP-I-1

PP-III-90Features of the Alcohols’ Dehydrogenation on the NZP – CatalystsDepending on the Location of the Ion - ModifierPylinina A.I., Povarova E.I., Mikhalenko I.I.Peoples’ Friendship University of Russia, Moscow, Russiapylinina@list.ruZirconium phosphates with NZPframework have a flexible structure that allows forheterovalent substitution in the cation and anion positions in the lattice without destroying it.This allows to vary the redox and acid-base properties of NZP catalysts, which makes thempromising catalysts.The purpose of this work was to study the influence of the replacement of Na + or Zr 4+ ions inNaZr 2 (PO 4 ) 3 by zinc, cobalt, nickel, and copper ions (M 2+ ) at various ratios and the M1–M2transition and red-ox properties of M 2+ on the catalytic activity of NZP in the model reactionof alcohols dehydrogenation.NZP catalysts were tested using a flow unit. The reaction mixture was analyzed by a FIDchromatograph.In case Na 1-2x M x Zr 2 (PO 4 ) 3 in which Na + ions were replaced by M 2+ = Co 2+ , Ni 2+ , Cu 2+ , theexperimental dehydrogenation activation energy E a decreased in passing through theT* = 310–340°C temperature; above this temperature, the electrophysical andcrystallographic phosphate properties changed. These changes were explained by thereversible transfer of Me 2+ ions from position M1 to M2 in the NZP lattice. Me 2+ centers withdifferent alcohol adsorption forms participated in the dehydrogenation reaction. For the firstform, E a and the logarithm of the pre-exponential factor linearly correlated with the ionicradius of M 2+ (fig.1).Fig.1. Correlation of the activation energy of formationof acetone with atomic radii at 200–300°С (Т < Т*) forsamples Na 1-2x M x Zr 2 (PO 4 ) 3 with х = 0.25Fig.2. Correlation of the dehydrogenation activationenergy and selectivity of MEK formation withstandard red-ox potentials for samples Na 3 ZrM(PO 4 ) 3247