高压下正戊醇的拉曼光谱原位研究

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。

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

Raman spectra in 800-3 000 cm~(-1) of 1-pentanol were studied under high pressure and at ambient temperature (23 ℃)using a cubic zirconia 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 in-creasing 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 93,0<(△_(Vp))_(single)(cm~(-1))≤23;P(MPa)=77.974 04·(△_(Vp))2 960,T=23℃+95.390 5,0<(△_(Vp))2 960(cm~(-1))≤21;P(MPa)=126.956 39·(△_(Vp))2 863,T=23℃-110. 648 09 where 0<(△_(Vp))_(2 863)(cm~(-1))≤13, respectively. The global slope is (_(Vsigle)/ P)T=(14±1)cm~(-1)·GPa~(-1), which can be 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 tempera-ture is 1.75 GPa. The molar volume change of the 1-pentanol is △Vm=1.84×10~(-6)m~3·mol~(-1) in the phase transformation from a liquid to a solid at 23 ℃.