高压下正戊醇的拉曼光谱原位研究

In-Situ Research on Raman Spectroscopy of 1-Pentanol under High Pressure

在室温(23℃)高压条件下,利用立方氧化锆压腔研究了正戊醇在波数800~3 000 cm-1范围内的拉曼光谱。拉曼谱峰随着压力的增大变得越来越尖锐,C—H伸缩振动峰在高压下不易被分离。在0.1 MPa^1.75 GPa,其C—H伸缩振动峰均随着压力的增大向高波数方向线性移动,拉曼频移与压力的线性拟合方程分别为:P(MPa)=69.652 65.(Δνp)single,T=23℃+105.806 93,0<(Δpν)single(cm-1)≤23;P(MPa)=77.974 04.(Δpν)2 960,T=23℃+95.390 5,0<(Δνp)2 960(cm-1)≤21;P(MPa)=126.956 39.(Δpν)2 863,T=23℃-110.648 09,0<(Δpν)2 863(cm-1)≤13。正戊醇的C—H伸缩振动单峰拟合的波数随压力的变化关系为(sνingle/P)T=(14±1)cm-1,适合用来标定体系压力。在压力为1.75 GPa时,正戊醇的拉曼谱峰有明显跳跃,同时镜下观察到其液-固相转变。液-固相转变过程中的摩尔体积变化为ΔVm=1.84×10-6m3.mol-1。

Raman spectra in 800-3 000 cm^-1 of 1-pentanol were studied under high pressure and at ambient temperature （23℃） using a cubic zireonia anvil cell. The Raman peaks become sharper at higher pressure so that each individual C -H stretching mode is difficult to be distinguished. The Raman frequencies of the C-H stretching modes shift to a higher position with increasing pressures ranging between 0. 1 MPa and 1.75 GPa. And the pressure induced frequency shifts are described by P（MPa） =69. 652 65 ·（△vp）single, T=23℃ ＋105. 806 93 where 0〈（△Vp）single （cm^-1 ）≤23 and P（MPa） =77. 974 04 · （△vp）2960. T=23℃ ＋ 95. 390 5 where 0〈（△vp）2 960 （cm^-1 ）421 and P（MPa）：126. 956 39 . （△vp）2863, T=23℃-110. 648 09 where 0〈（△vp）2863 （cm^-1） 413, respectively. The global slope is （δvsinglc/δP）T （14＋1）cm^-1 . GPa^-1, which can he used as a pressure sensor. Both the jumping of the frequencies and the figure under microscope indicate that the frozen pressure of the 1-pentanol at room temperature is 1.75 GPa. The molar volume change of the 1-pentanol is △Vm=1.84×10^-6m^3·mol^-1 in the phase transformation from a liquid to a solid at 23℃.