ACETIC ACID PRODUCTION METHOD.

摘要

This production method for producing acetic acid suppresses concentration of hydrogen iodide and improves the liquid separation of overhead from a distillation tower. A mixture including hydrogen iodide, water, acetic acid, and methyl acetate is distilled in a first distillation tower (3); the overhead, and a side-cut stream or bottom-product stream including acetic acid are separated from this mixture; the overhead is cooled in a condenser (C3) and condensed; the condensed liquid is separated into an upper phase and a lower phase by a decanter (4); and acetic acid is produced. In this method, a mixture having a water concentration of at least an effective amount and no more than 5 wt% (e.g., 0.5-4.5 wt%) and a methyl acetate concentration of 0.5-9 wt% (e.g., 0.5-8 wt%) is supplied to the distillation tower and distilled. As a result, a region having a high water concentration is formed inside the distillation tower at a position higher than the supply position for the mixture, hydrogen iodide and methyl acetate are reacted in this high water-concentration area, and methyl iodide and acetic acid are generated.