| 摘要 |
PURPOSE:To remove impurities having polymerization-suppressing or polymerization-inhibiting action from crude acrylic acid produced by the catalytic vapor-phase oxidation of propylene, etc., by treating the crude acrylic acid with an aqueous solution of a bisulfite and then with a hydrazine. CONSTITUTION:A reaction product gas obtained by the catalytic vapor-phase oxidation of propylene or acrolein is cooled and condensed to obtain an aqueous solution of acrylic acid, which is distilled or evaporated to remove the components having low-boiling point. The aqueous solution of acrylic acid to be extracted and/or the acrylic acid solution obtained from the extraction process and containing extraction solvent are mixed with an aqueous solution containing a bisulfite in an amount of 0.5-15wt%, especially 1-10% based on the acrylic acid. Acrylic acid having high purity and quality is produced by adding 0.001-1%, especially 0.01-0.5% hydrazine compound to the separated and recovered acrylic acid solution in either of the following solvent-separation, low-boiling component separation, high-boiling component separation and redistillation processes (preferably added to the distillate after the separation of the high-boiling component).
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