反应详情

This example relates to FIG. 1. In this example a 95 wt % solution of aqueous maleic acid is provided as described in Example 1. The aqueous maleic acid is fed to the mono-ester reactor column (9). Recycled methanol from the refining section (line 16a) is fed to the bottom of the column 9. More than 80% of the maleic acid is converted to mono-methyl maleate from the bottom product line (line 17) contains less than 10 mole % water. Mainly water and methanol and a small amount of maleic acid in the overhead (line 14) are fed to the methanol column (line 25). The bottom product from column (9) is fed to a reaction column (19) to react the mono-methyl maleate with methanol to produce di-methyl maleate. 300 mols per hour of methanol (line 24) are fed to the bottom of the reaction column (19). Essentially water free, fully converted di-methyl maleate is fed (line 26) to hydrogenation in reactor (20). Recycle methanol from the refining section is fed to the top of the reaction column as wash (line 16b) to minimise the di-methyl maleate and maleic acid in the overhead of the column. Methanol and water from the overhead (line 31) of the reaction column is fed to the methanol column (25) where the methanol is separated and recycled to the reaction column (line 24). Water and a small amount of recovered maleic acid and di-methyl maleate from the bottom of the methanol column are recycled to the absorber (2) in line 3.