| 摘要 |
PURPOSE:To obtain pyruvic acid or its ester in an industrially advantageous manner by reaction between methacrylic acid or its ester and hydrogen peroxide using a heterogeneous chromium-silicalite catalyst and by filtering off the catalyst after reaction. CONSTITUTION:The objective pyruvic acid or its ester can be obtained by oxidative scission with hydrogen peroxide of the double bond of methacrylic acid or its ester using a heterogeneous chromium-silicalite catalyst. For this catalyst, it is preferable that the atom ratio Si/Cr be 25-200 and the molar ratios OH/SiO2 and H2O/SiO2 0.3-1.0 and 30-100, respectively. With the present method, the catalyst can be separated and recovered through filtration to carry out the next distillation operation. It is also possible to make a reaction in an aqueous solution using free methacrylic acid. In particular, use of methacrylic acid will facilitate the separation of the product through distillation because of large boiling point difference between the raw material and the final product. |
