PURPOSE: To obtain the titled compound in high selectivity in high yield, by oxidizing acrolein or methacrolein with O2 at high temperature in a gaseous phase by the use of a catalyst having high selectivity, life, and utility prepared by adding K, Cu, Fe, etc. to a system consisting of P-Mo-V.
CONSTITUTION: In preparing acrylic acid or methacrylic acid by oxidizing catalytically acrolein or methacrolein with O2 at high temperature in a gaseous phase, a catalyst (e.g., catalyst shown by the formula II, etc.) shown by the formula (X is one or more selected from K, Rb, Cs, and Tl; Y is one or more selected from Cu, Si and Sb; Z is one or more selected from Ni, Mn, and U; a=0.5W6; b=12, c=0.2W6; d=0.01W6; e=0.01W6; f=0.01W6) is used.
EFFECT: Highly catalytic activity can be maintained for a long period.
MATSUZAWA HIDEO
KOBAYASHI MASAO
ISHII HIROMICHI
