| abstract |
A process for producing methacrotein and methacrylic acid by vapor phase oxidation of isobutylene and/or tertiary butanol with molecular oxygen or a molecular oxygen-containing gas in the presence of the catalyst represented by the following formula:n (wherein X represents at least one element selected from the group consisting of Cu, Ag, Zn, Cd, Al. Ge. Sn, Pb, Sb, Bi, Mg, Ca, Sr, Ba, Ti, Zr, Nb, Ta, W, Mn, Fe, Co, Ni, Ce, Th, Re, Cr, B, K. Rb and Cs, and a, b, c, d and e represent the atomic ratio of the elements where, a is 10, b is a number of 6 or less than 6 excluding 0, preferably 0.5 to 3, c is a number of 0.5 to 10, preferably 0.5 to 3, d is a number 0.01 to 5, preferably 0.01 to 2.0, and a is a number determined depending on the valency and atomic ratio of the other elements present and is usually a number of 35 to 80). |