Oxidation of methylacrolein to methacrylic acid on phosphomolybdic acid modified by alkaline metal ions and NH4+

The structure of catalysts prepared by phosphomolybdic acid modification by ions of alkaline metals and NH4+ was studied. It is shown that introduction of Li+ and Na+ results in the formation of monophase salts of the acid, and K+, Cs+ and NH4+ introduction leads to the formation of two-phase systems. Thermal and catalytic stability of the catalyst is determined by the size of cation introduced into the acid. The highest values of activity and selecticity of methacrylic acid formation during oxidation of methyl-acrolein were observed for the case of two-phase systems, were different phases perform different functions and intensify the catalytic effect