Crystalline Mo-V-W-mixed Oxide with Orthorhombic and Trigonal Structures as Highly Efficient Oxidation Catalysts of Acrolein to Acrylic Acid.

We succeeded in introducing W in MoVO with keeping the orthorhombic, trigonal, and amorphous structures. Synthesized crystalline Mo(W)VO with orthorhombic and trigonal structures, both of which possess heptagonal channels, showed catalytic activity for gas-phase selective acrolein oxidation to acrylic acid superior to amorphous Mo(W)VO and to tetragonal MoVO. The results strongly suggest that the crystalline Mo(W)VO with orthorhombic and trigonal structures are real active phase of industrial acrolein oxidation catalysts based on Mo, W, and V oxides. Furthermore, we found that the resulting W-containing catalyst showed less-dependency of water partial pressure in the reactant feed on the acrolein conversion. [ABSTRACT FROM AUTHOR]