| 摘要 |
<p>A method for producing high-quality epsilon-caprolactam, which comprises: a crystallization step wherein epsilon-caprolactam is crystallized at a crystallization temperature of 10°C or higher but less than melting point of the lactam from a mixed solution that is obtained by mixing crude epsilon-caprolactam, which has been obtained by Beckmann rearrangement of cyclohexanone oxime, with an organic solvent, thereby obtaining a slurry liquid that contains epsilon-caprolactam crystals; a first solid-liquid separation step wherein the slurry liquid obtained in the crystallization step is separated into a liquid phase that contains the organic solvent and a solid phase that contains the epsilon-caprolactam crystals, thereby obtaining the epsilon-caprolactam crystals; a repulp cleaning step wherein the epsilon-caprolactam crystals obtained in the first solid-liquid separation step are subjected to repulp cleaning using an organic solvent at a temperature not less than the above-mentioned crystallization temperature but less than the melting point of epsilon-caprolactam, thereby obtaining a slurry liquid that contains epsilon-caprolactam crystals; and a second solid-liquid separation step wherein the slurry liquid is separated into a liquid phase that contains the organic solvent and a solid phase that contains the epsilon-caprolactam crystals, thereby obtaining high-quality epsilon-caprolactam.</p> |
