Statistical Characteristics of Raman Shift of Petroleum Components Ⅱ: Cycloparaffin and Unsaturated Hydrocarbon
CHEN Yong1, 2, LIU Wei-yi1, 2, WANG Xin-tao1, 2, ZHUO Qin-gong3, WANG Miao1, 2, CAO Meng-chun1, 2, ZHOU Zhen-zhu4, CHEN Xiao-lan4
1. School of Geosciences, China University of Petroleum, Qingdao 266580, China
2. Laboratory for Marine Mineral Resources, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, China
3. PetroChina Exploration and Development Institute, Beijing 100083, China
4. College of Earth Science and Engineering, Shandong University of Science and Technology, Qingdao 266590, China
Abstract：Understanding the Raman spectra of different types of hydrocarbons is fundamental for analyzing hydrocarbon inclusions 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 1 440~1 460 cm-1. But cyclopentane and cyclohexane 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 1 460 cm-1. The strongest Raman peak of C—C bond cyclopentane appears at 1 445, 1 450 and 1 460 cm-1 corresponding 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 1 460 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 1 440~1 460 cm-1. Cyclohexane containing one branch chain which can be identified by stable Raman band at 1 445 cm-1±, 1 034 cm-1± and 2 853 cm-1±, 2 934 cm-1±. The combination of strongest Raman peaks at 1 440~1 460 and 2 926 cm-1 are the evidence of the cyclohexane containingtwo branch chains, while the strongest Raman peaks of 1 459 cm-1± and 2 924 cm-1± are the evidence of the cyclohexane containingthreebranch chains. The CC bonds of alkene can be identified by 1 641 cm-1±, and the CC bonds of alkyne can be identified by 1 445 cm-1±, 2 908 cm-1± and 2 933 cm-1±. All these typical Raman bands can be used to identify cycloalkanes and alkynes.
