毛细管气相色谱法研究异戊二烯和马来酸酐的反应程度

用毛细管色谱法研究了带侧链二烯烃中最简单的异戊二烯同马来酸酐发生Ｄｉｅｌｓ－Ａｌｄｅｒ反应的反应程度．考察了不同的反应温度、反应时间、马来酸酐用量、催化剂类型及用量等对转化率的影响。在选用油样的最佳反应条件下，不加催化剂转化率不到４０％，加催化剂提高到７９％。结果表明，在双烯加成反应中许多共轭二烯烃（具有不易反应的取代基团及构象）并不完全与亲双烯体反应，马来酸酐测定油品二烯值方法（ＵＯＰ－３２６法）只是一个相对方法，揭示了该法对某些油栏分析结果较其它方法严重偏低的原因。

A Study of Reaction Degree for Isoprene-Maleic Anhydride Addition Reaction by Capillary Gas Chromatography

In the article, the degree of the Diels-Alder reaction of isoprene─the simplest ofconjugated dienes bearing side chain──with maleic anhydride was studied with capillarygas chromatography.The effects on conversion of different reaction conditions such asreaction temperature, catalyst type and amount of catalyst added etc,were studied.Underoptimum conditions and With catalyst the reaction conversion is up to 79%;without catalyst,it may be as 40%. The results show that many conjugated dienes having noreactive Substituent groupS and construction do not react completely with dienophiles,andthat the UOP-326 method employing maleic anhydride for the determination of oil products is only a relative metbod.This explains the low values resulting from determinations usingthis method for some samples of oil products,as compared to results from othermethode.