Role of Crystalline Structure in Allyl Alcohol Selective Oxidation over Mo3VO x Complex Metal Oxide Catalysts.

The role of the crystalline phase of Mo₃VO _x in the catalytic oxidation of allyl alcohol over four kinds of crystalline (orthorhombic, trigonal, tetragonal, amorphous) Mo₃VO _x catalysts was investigated to determine the active sites for the reactions. Tetragonal Mo₃VO _x was found less active for the formation of acrylic acid from allyl alcohol, although acrolein was obtained selectively at higher temperature. For orthorhombic and trigonal Mo₃VO _x catalyst, allyl alcohol converted to acrolein and propanal competitively at the mouth of the heptagonal channel over the a- b plane of the rod-type crystalline particles, and these aldehydes were oxidized consecutively to acrylic acid. Acrylic acid was formed effectively at increased reaction temperature over orthorhombic, trigonal and amorphous Mo₃VO _x catalysts, and the maximum yields of acrylic acid were 73 % for the orthorhombic Mo₃VO _x catalyst and 72 % for the trigonal Mo₃VO _x catalyst at 350 °C. [ABSTRACT FROM AUTHOR]