| 摘要 |
PROBLEM TO BE SOLVED: To provide an industrially advantageous method for efficiently producing high-purity HPA and/or its dimer in a simple process. SOLUTION: The method for obtaining high-purity hydroxypivalaldehyde and/or its dimer by reacting isobutylaldehyde and formaldehyde in the presence of a basic catalyst, adding a diluent to an aqueous solution obtained by distillating off low-boiling components including unreacted isobutylaldehyde, crystallizing hydroxypivalaldehyde and/or its dimer by cooling the aqueous solution, separating a solid from the aqueous solution and washing the solid with an organic solvent and/or water, is characterized by diluting the aqueous solution containing the hydroxypivalaldehyde and/or its dimer which is obtained by distillating off the low-boiling components with the diluent and a basic compound so that the concentration of the hydroxypivalaldehyde and/or its dimer is 5 to 23% by mass, the concentration of the formaldehyde is 0.2 to 2.5% by mass and that the pH is not lower than 5.0, and crystallizing in the temperature range of 20 to 45°C followed by solid/liquid separation. COPYRIGHT: (C)2007,JPO&INPIT
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