| 摘要 |
PURPOSE:To prepare methacrylic acid in high efficiency, by the two-step vapor phase catalytic oxidation of isobutylenen, using a delivery solution containing methacrylic acid from the latter separation process as the absorbent for the reaction product of the former oxidation process. CONSTITUTION:Methacrylic acid is prepared by catalytically oxidizing isobutylene and/or t-butanol with molecular oxygen in vapor phase in the presence of a catalyst, and then catalytically oxidizing the formed methacrolein in vapor phase. In the above preparation process, the unreacted methacrolein and the formed methacrylic acid are separated from the reaction product in the latter oxidation process, as a solution, e.g. by cooling and liquefaction. The separated solution is countercurrently contacted with the reaction product in the former oxidation process to absorb the by-produced methacrylic acid and acetic acid and high boiling point by-products to the solution and, at the same time, to vaporize methacrolein contained in the solution. The methacrolein vapor thus liberated is circulated to the latter oxidation reaction process. |
