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萘醌是萘氧化制苯酐过程中的重要副产物,其含量是苯酐生产工艺控制的指标之一。它的分析在国外一般采用色谱法使其与其它组份同时测定,操作简便,准确度高;在国内大都仍采用碘量法或光电比色法测定。不同分析方法的比较:1.碘量法:其原理是萘醌在溶液中与过量盐酸作用产生游离氯,氯与碘化钾作用析出的碘用硫代硫酸钠滴定,以淀粉为指示剂。
Naphthoquinone is an important by-product in the process of naphthalene oxidation to phthalic anhydride. The content of naphthoquinone is one of the indicators for the control of phthalic anhydride production process. Its analysis in foreign countries generally use chromatography to make it with other components at the same time determination, easy to operate, high accuracy; in most of the country are still using iodometric or photoelectric colorimetric determination. Comparison of different analytical methods: 1. Iodometry: The principle is naphthoquinone in solution with excess hydrochloric acid to produce free chlorine, chlorine and potassium iodide precipitation of iodine with sodium thiosulfate titration to starch as an indicator.