26℃和常压至1.5 GPa压力下2-甲基戊烷拉曼光谱研究

利用碳化硅压腔在常压至1.5 GPa和26℃条件下对液态2-甲基戊烷进行了拉曼光谱测量,讨论了C-H拉曼峰频率、强度、面积、以及谱峰宽度随压力升高的变化规律.实验结果表明,2-甲基戊烷的拉曼位移在2 800～30 00 cm-1范围内的CH3和CH2的伸缩振动谱峰随着压力的增大均连续向高波数位移,其拉曼位移与压力的关系可以表示为vas(CH3)=0.013 1p 2 960.1,vs(CH3)=0.008 8p 2 871.0,vas(CH2)=0.008 9p 2 930.2,vas(CH2)'=0.007 0p 2 903.1和vs(CH2)=0.007 9p 2 844.7.另外处理实验结果时发现,在0～1.5 GPa条件下,2-甲基戊烷的vas(CH3)拉曼位移可以进行压力标定,其方程为:P(MPa)=76.2(Δvp)2 960 21.65(r2=0.995 8).该压力体标定剂,适合于不希望有Si和Al等元素出现的体系.

Research on Raman Spectra of 2-Methylpentaneat at Pressure of 0-1.5 GPa and Temperature of 26 ℃

The present paper investigates the Raman spectral character of liquid 2-methylpentane by an experiment at the pressure of 0-1.5 GPa and the temperature of 26 degrees C, and defines the relation between the pressure and the Raman peak of 2-methylpentane at ambient temperature. The result shows that there are five characteristic Raman peaks in 2-methylpentane defined as v (CH2) and v(CH3), and all of them move to high position as the system pressure increases. The relation between the system pressure and peaks positions is given as following: v(as), (CH3) = 0.013 1p + 2 960.1, v(s), (CH3) = 0.008 8p + 2 871.0, v(as) (CH2) = 0.008 9p + 2 930.2, v(as) (CH2), = 0.007 0p + 2 903 and v(s) (CH2) = 0.007 9p - 2 844.7. On the other hand, 2-methylpentane is reliable as a liquid pressure gauge for high pressure experiment. The equation applied to demarcate system pressure is also showed: p (MPa) = 76.2 (deltav(p))2 960 + 21.65(r2 = 0.995 8). This is probably the first organic liquid gauge, especially for systems not expected to emergence of Si, Al and hydroxyl matter.