To provide -caprolactam having extremely high Pz which is an index of the amount of impurities included in the -caprolactam, useful for raw material or the like of a polyamide resin.
This -caprolactam includes less than 25 ppm of impurities observed by the following method. The high purity -caprolactam is manufactured by adjusting the purification condition of the -caprolactam according to the monitored amount of the impurities. (Measuring method) -caprolactam is selectively fractionated by injecting -caprolactam to the first column (a fused silica capillary column using polyethyleneglycol 20M bonded with 2- nitroterephthalic acid as the stationary phase), fractionating the effusing components including the subject components of the just before the effusion of the -caprolactam. The fractionated component is injected to the second column (a fused silica capillary column using 5% phenylmethylsilicone as the stationary phase), fractionated and the subject component is detected by a FID detector.
HARA KAZUO
TANAKA KATSUMI
