| abstract |
Kind Code: A1 The present invention relates to a method for producing acrylic acid and (meth) acrylic acid ester, and efficiently and stably separates by-products from the reaction product, thereby obtaining high-purity acrylic acid and (meth) acrylic acid ester. To get. A near-infrared spectrometer is provided on a process liquid transfer line obtained in an arbitrary manufacturing process, and the concentration of impurities contained in the process liquid is analyzed online, and the analysis result is used as an index. In the process, predetermined adjustment is performed so that the analysis target component can be stably maintained at a desired value. [Selection figure] None |