IMPROVED METHOD FOR PURIFYING AND PHARMACEUTICALLY PREPARING ORTHO-PHTHALALDEHYDE

摘要

PROBLEM TO BE SOLVED: To provide an improved method for purifying crude o- phthalaldehyde(OPA) that can simply and safely purify crude o-phthalaldehyde substantially quantitatively and give extremely stabilized o-phthalaldehyde causing no agglomeration even after a lapse of years. SOLUTION: Relating to improved method for purifying and pharmaceutically preparing o-phthalaldehyde, the crude OPA given by acidic hydrolysis of OPA acetal, if necessary, adding basic aqueous solution to adjust the pH to 1-8, then the phase separation is carried out. The water in the aldehyde-including phase is distilled off in a thin layer evaporator under very short thermal stress of <1 minute at room temperature to 180 deg.C and the pressure of 100 mbar to the atomic pressure. Then, the objective OPA is distilled out from the evaporation residue by using a thin layer evaporator under very short thermal stress of <1 minute at 80-180 deg.C jacket temperature and 0.5-50 mbar pressure and the resultant OPA melt is pelletized at 60-80 deg.C under atmospheric pressure.