石油组分的拉曼位移特征统计分析Ⅱ:环烷烃和不饱和烃

Statistical Characteristics of Raman Shift of Petroleum Components Ⅱ:Cycloparaffin and Unsaturated Hydrocarbon

了解不同类型烃类的拉曼光谱特征有助于更好地利用拉曼光谱技术分析烃类包裹体。主要统计和分析了环烷烃和不饱和烃的典型拉曼位移特征。结果显示,环戊烷和环己烷C—C键最强拉曼峰主要集中在1 440~1 460cm^(-1)之间,而通过环戊烷和环己烷分别在890和785cm^(-1)的稳定特征峰可以进行区分。环戊烷随着支链数的增加,其C—C键最强拉曼峰的波数增大至1 460cm^(-1)。含一个支链的五元环烷烃C—C键最强拉曼峰位于1 445cm^(-1),含两个支链的五元环烷烃C—C键最强拉曼峰为1 450cm^(-1),含三个及以上支链的五元环烷烃C—C键最强拉曼峰为1 460cm^(-1)。环己烷随着支链数增加C—H键最强拉曼峰发生红移,C—C键最强拉曼峰主要分布在1 440~1 460cm^(-1)范围内。含一个支链的环己烷最强拉曼峰组合特征明显,分布在1 445cm^(-1)±,1 034cm^(-1)±,2 853cm^(-1)±和2 934cm^(-1)±,含两个支链的环己烷C—C键分布在1 440~1 460cm^(-1),C—H键的最强拉曼峰为2 926cm^(-1)±,含三个支链的环己烷具有1 459cm^(-1)±和2 924cm^(-1)±的最强拉曼峰组合。烯烃碳碳双键的特征峰为1 641cm^(-1)±。炔烃特征峰在2 200cm^(-1)±,而1 445cm^(-1)±,2 908cm^(-1)±和2 933cm^(-1)±三个强峰可作为辅助识别标志。这些特征可以用于识别烃类包裹体中的环烷烃和不饱和烃。

Understanding the Raman spectra of different types of hydrocarbons is fundamental for analyzing hydrocarbon inclu-sions with Raman spectroscopy.In this paper,statistics and analysis were done for the Raman characteristics of cycloalkanes and unsaturated hydrocarbons.According to the statistical results,some important conclusions can be drawn.The strongest Raman peak of C—C bond of cyclopentane and cyclohexane mainly concentrated in 1440～1460 cm-1 .But cyclopentane and cyclohex-ane can be distinguished by the stable characteristic peak at 890 and 785 cm-1 in the Raman spectrogra.With the increasing of the number of branch chain of cyclopentane,the wave number of the strongest Raman peak of C—C bond will also increase,and reach to 1460 cm-1 .The strongest Raman peak of C—C bond cyclopentane appears at 1445,1450 and 1460 cm-1 correspond-ing to one,two and three or more than three branch chains respectively.The strongest Raman peak of C—C bond cyclopentane containing four chains is constant at 1460 cm-1 .With the increasing of the number of branch chain of cyclohexane,the wave number of the strongest Raman peak of C—H bond will decrease.The strongest Raman peak of C—C bond is mainly distributed in the range of 1440～1460 cm-1 .Cyclohexane containing one branch chain which can be identified by stable Raman band at 1445 cm-1 ±,1034 cm-1 ± and 2853 cm-1 ±,2934 cm-1 ±.The combination of strongest Raman peaks at 1440～1460 and 2926 cm-1 are the evidence of the cyclohexane containingtwo branch chains,while the strongest Raman peaks of 1459 cm-1 ± and 2924 cm-1 ± are the evidence of the cyclohexane containingthreebranch chains.The C =C bonds of alkene can be identi-fied by 1641 cm-1 ±,and the C≡C bonds of alkyne can be identified by 1445 cm-1 ±,2908 cm-1 ± and 2933 cm-1 ±.All these typical Raman bands can be used to identify cycloalkanes and alkynes.