PROCESS FOR PRODUCING METHACRYLIC ACID AND CATALYSTS FOR THE PROCESS.

摘要

A catalyst for the production of methacrylic acid by the oxidation of methacrolein with oxygen in the gas phase has the formula: PaMobVcFedCueZfXgYhOi where X is K, Rb, Cs and/or Tl- Y is Te, La, B, Ag, Cr, Mg and/or Ba; Z is Zr or Sb; a = 0.3-4; b = 12; c = 0.01-3; d = 0.01-4; e = 0.01-3; f = 0.01-3; g = 0.01-3; h = 0.001-5; i is the number of oxygen atoms required to satisfy the valencies of the other elements present. The catalyst is prepd. by pyrolysis of a mixt. of cpds. of the elements present in appropriate ratio. The prepn. of methacrylic acid is carried out by passing methacrolein (1-20% by wt.) and oxygen (0.3-4 moles per mole of methacrolein) in an inert carrier gas (such as nitrogen, steam or carbon dioxide) over the catalyst at 230-450 deg. C.