| 摘要 |
PROBLEM TO BE SOLVED: To provide a saponification value testing method, for example, of a lubricant for industry that has improved in reproducibility and analysis accuracy and is automated. SOLUTION: After 1-20g sample, 2-butanone, and potassium hydroxide solution are sampled, the above sample is heated while being refluxed to obtain a saponification liquid, then hydrocarbon such as naphtha and ethylalcohol are added to the saponified liquid to prepare a measurement liquid, and then the measurement liquid is subjected to potential difference titration using a nitric acid with a known concentration. The amount of ethylalcohol to be added is preferably 0.27-0.6 times as large as the volume of the saponified liquid and the amount of sampled 2-butanone is preferably 25±1ml.
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