| 摘要 |
PURPOSE:To provide continuous production method of slightly soluble reactional products such as terephthalic acid or naphthalenedicarboxylic acid adhering to a container wall, etc., by readily and accurately detecting liquid height in a reaction tank in continuous production of the reactional products. CONSTITUTION:The characteristics of this continuous production method of slightly soluble substance comprises measuring pressure of solvent supplied through a solvent feed opening formed in a liquid phase part in a reaction tank for forming a slightly soluble reactional product and pressure of a vapor- phase part in the reaction tank, converting difference in the pressures into height of liquid level of the reaction solution or a retention time in the reaction tank and controlling the extraction rate of the reaction solution so as to make the converted value in a fixed range. |
