PURPOSE: To purify the titled compound extremely useful as an acylating agent in high purity with good hue in a short time without requiring a high reaction temperature and deteriorating quality, by distilling away volatile impurities contained in an acyl halide using a specific distiller.
CONSTITUTION: Volatile impurities contained in an acyl halide obtained by reacting a phosphorus halide compound with a carboxylic acid are removed. In the process, a thin-film distiller, e.g., Smith's or Luwa' thin-film distiller, is used to charge the acyl halide into a dripping vessel thereof and the interior of the distiller is kept at ≤100mmHg, preferably ≤10mmHg vacuum degree by a vacuum pump, etc. The heating surface in the interior of the distiller is then kept at 50W220°C, preferably 90W190°C to drip the acyl halide in the dripping vessel and remove the contained volatile impurities. Thereby the acyl halide of high purity is obtained.
IWAMA TAKASHI
TAKAHASHI FUJIO
KADOMA YOSHIHITO
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