Catalytic dehydrogenation of propanol-2 on Na-Zr phosphates containing Cu, Co, and Ni

Abstract

The dehydrogenation of propanol 2 on sodium zirconium phosphates (NZP) with the composi tion Na 1 ⎯ 2x M x Zr 2 (PO 4 ) 3 (x = 0.125 and 0.25) in which Na + ions were replaced by M 2+ = Co 2+ , Ni 2+ , and Cu 2+ ions was studied. The experimental reaction activation energy E a decreased while transition through the T* = 310-340°C temperature; above this temperature, the electrophysical and crystallographic properties of the material changed. These changes were explained by the reversible transfer of Me 2+ ions from position M1 to M2 in the NZP lattice. Me 2+ centers with different alcohol adsorption forms at T < T* (one point) and T > T* (two point) participated in the dehydrogenation reaction. For the first form, E a and the logarithm of the preexponential factor linearly correlated with the ionic radius of M 2+ . The activity of M NZP catalysts altered in repeated experiments and in cases when the direction of temperature variations changed.

Conversion of isopropyl alcohol over Ru and Pd loaded N-doped carbon nanotubes

“…It might be noted that the values obtained are in good agreement with the results by other authors [54].…”

Synthesis and catalytic properties of M0.5(1 + x)Fe x Ti2 − x (PO4)3 (M = Co, Ni, Cu; 0 ≤ x ≤ 2) for methanol conversion reactions

“…They are renowned for their high structural stability and high cation mobility, the latter being due to the presence of a three dimensional system of channels in their crystal structure [3][4][5][6][7][8][9][10][11]. Such phosphates have attracted researchers' attention in studies of catalytic processes of acid-base (isomerization and dehydra tion) and redox (selective oxidation and dehydrogena tion) conversion of hydrocarbons and alcohols [11][12][13][14][15][16][17][18][19]. In particular, conversion reactions of С 1 -С 4 ali phatic alcohols have been investigated not only for framework zirconium and thorium phosphates of group I and II metals [12][13][14][15][16] but also for materials containing transition metals (Cu, Fe, Mo, or Ni) in the channels of the NASICON structure or in those of a given structure [17][18][19].…”

“…Such phosphates have attracted researchers' attention in studies of catalytic processes of acid-base (isomerization and dehydra tion) and redox (selective oxidation and dehydrogena tion) conversion of hydrocarbons and alcohols [11][12][13][14][15][16][17][18][19]. In particular, conversion reactions of С 1 -С 4 ali phatic alcohols have been investigated not only for framework zirconium and thorium phosphates of group I and II metals [12][13][14][15][16] but also for materials containing transition metals (Cu, Fe, Mo, or Ni) in the channels of the NASICON structure or in those of a given structure [17][18][19]. Changes in the qualitative and quantitative compositions of the framework phos phates led to changes in their catalytic activity and selectivity for alcohol conversion (relationship between dehydration and dehydrogenation products), primarily because of changes in the acidity, specific surface area, and particle size of the catalysts.…”