环己烷氧化反应混合物的全分析方法

Analysis of Reaction Mixtures in the Oxidation of Cyclohexane

为了建立一套完整可靠的环己烷氧化反应混合物中各组分的全分析新方法,在比较各种分析方法适应性的基础上,确立了用液相色谱法分析其中的己二酸、戊二酸和丁二酸(简称三酸),用气相色谱法分析其中的环己烷、环己醇和环己酮,用化学滴定法分析其中的环己基过氧化氢和己二酸环己酯的联合分析法.通过研究液相色谱中紫外检测波长、流动相组成、流动相pH值、流速等因素对三酸分离效果的影响,确定了分离三酸的最佳条件:液相紫外检测波长为212nm,流动相为甲醇的体积分数为15%～30%的磷酸二氢钾缓冲溶液(pH值为3～4).流速为0.8mL/min,并分析了3种分析方法的可靠性.结果表明,3种分析方法的相对标准偏差均小于0.71%.

To fully analyze the reaction mixtures from cyclohexane oxidation, a united analyzing method was established based on the comparison of feasibility of all kinds of analysis methods, including analyzing adipic acid, glutaric acid, and succinic acid （abbreviation ＂ three acids＂） by HPLC technique, analyzing cyclohexane, cyclohexanol, and cyclohexanone by GC technique, and analyzing the peroxide and ester by chemical titration. In order to make an accurate analysis of the ＂three acids＂ in the reaction mixtures by HPLC, the effects of several factors such as UV wavelength, mobile phase composition and its pH value, and mobile phase flow rate, on the retention time and separation efficiency of the ＂three acids＂ were investigated. It was found that the optimal conditions for the separation of the ＂three acids＂ were： the UV wavelength was 212 nm, the composition of flow phase was potassium dihydrogen phosphate-methanol buffered solution with 15%-30% methanol and its pH = 3- 4, and the flow phase velocity was 0.8 mL/min. In addition, the precision and accuracy of the above three analytical methods were analyzed, and the results showed that the relative standard deviations of the three analysis methods were less than 0.71%, confirming that the chemical analysis method was reliable.