| 摘要 |
PURPOSE:The gas-phase catalytic oxidation of methacrolein with molecular oxygen is carried out using a specific catalyst composition containing molybdovanadophosphoric acid to enable the production of methacrylic acid in high yield in highly stabilized operations for a long period of time. CONSTITUTION:The gas-phase catalytic oxidation of methacrolein with molecular oxygen or a gas containing the same in the presence of an inert gas diluent is carried out in the presence of a catalyst composition containing molybdovanadophosphoric acid of the formula (X is K, Rb, Cs, Tl; Y is Sc, Y, La, Ce, Pr, Nd, Pm, Sm; Z is Cu, As, Sb, Co, Zr, Bi, Ti, Te, Ag; a-g are molecular ratios of individual elements; when a is 12, b, c and d are 3 or less other than 0; F is 0-3; g depends on valencies and atomic ratios of other elements) at a space velocity of 100-5,000hr<-1>, 200-350 deg.C under about normal pressure to give methacrylic acid. The molybdovanadophosphoric acid is prepared in the presence of a nitrogen-containing heterocyclic compound such as pyridine. |
