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氮丙啶化合物的含环率是该类化合物的重要性能指标,在氮丙啶化合物的合成与应用过程中,需要准确地测定它们的含环率。关于氮丙啶含环率的测定工作,前人多采用滴定法,即硫代硫酸钠法、硫氰酸法、高氯酸法等,这些方法都是常量法。1972年等报道了用硫氰酸钾的微量电位滴定法,其应用范围有局限性。我们在测定氮丙啶化合物含环率的过程中,遇到了开环后是仲胺型具碱性的化合物,用该法不能测定其含环率,为此,我们改进并发展了微量电位滴定法,不仅减少了试剂和样品的消耗量,而且适用范围广、结果准确。硫氰酸钾法原理是硫氰酸钾与对甲苯磺酸反应所产生的硫氰酸与氮丙啶环进行等当量亲核加成,过量的对甲苯磺酸用氢氧化钾—甲醇溶液反滴定。与硫化硫酸钠不同,硫氰酸钾在酸性介质中足比较稳定的。
The aziridine compound ring rate is an important performance indicators of these compounds, aziridine compounds in the synthesis and application process, the need for accurate determination of their ring rate. About the determination of aziridine ring rate, many people use titration, sodium thiosulfate method, thiocyanate method, perchloric acid method, these methods are constant method. 1972 reported the use of potassium thiocyanate micro-potential titration, the scope of its application. In the determination of the aziridine compound ring rate, we have encountered after the ring is a secondary amine with alkaline compounds, the method can not be measured with the ring rate, therefore, we improve and develop the micro-potential titration Act, not only reduces the consumption of reagents and samples, but also a wide range of applications, the results are accurate. The principle of potassium thiocyanate is the equivalent nucleophilic addition of thiocyanate and aziridine ring generated by the reaction of potassium thiocyanate with p-toluenesulfonic acid. The excess p-toluenesulfonic acid is treated with potassium hydroxide-methanol solution Titration. Unlike sodium sulphurate, potassium thiocyanate is relatively stable in acidic media.