马来酸酐法分析汽油中共轭二烯烃可靠性探讨

The Study on the Reliability of Maleic Anhydride Method in Determinating Conjugated Dienes in Gasoline

研究了测定含烯汽油中共轭二烯烃含量的马来酸酐法（ＵＯＰ—３２６法）的准确性问题．ＵＯＰ—３２６法基于马来酸酐与共轭二烯烃的双烯合成反应机理，由于汽油中含有各种不同取代基和立体构象的共轭二烯烃，取代基团越大反应越困难．以所带取代基团最小（－ＣＨ３）和碳数最少的共轭二烯──２－甲基─１，３─丁二烯（以下称异二烯）为例．考察了在不同条件下的转化率，用毛细管气相色谱法测定异戊二烯含量，结果表明，在最佳反应条件及有催化剂存在下，转化率最高为７６．３％．因此，ＵＯＰ—３２６法不能准确测定汽油中共轭二烯烃含量．

Accuracy of Maleic Anhydride Method (UOP326 Method) is studied in deterrnination of the conjugated dienes in olefinic gasoline. The method is besed on the machanism of diene synthetic reaction of maleic anhydride with conjugated dienes. The olefinic gasoline contains conjugated dienes with various substituents and stereomerides, therefore the auction degree of the diene synthesis varisS greatly. the conversion level of the isoplene with maleic anhydride was studied under different condition, and the content of isoprene was determinated by capillary gas chromatography. Under tile optimum reaction condihon and in the presence of catalyst the conversion level can be up to only 76.3percent, therefore UOP326 method is not accurate for the determination of conjuged dienes in olefinic gasoline.