高压下正戊烷的稳定性研究

 利用Raman散射光谱在碳硅石压腔下研究了常温下的正戊烷从0.07~4.77 GPa的稳定性。结果表明：正戊烷的 CH₃、CH₂对称和反对称伸缩振动2 877 cm^-1、2 964 cm^-1和2 856 cm^-1、2 935 cm^-1以及－(CH₂)_n －同步扭曲振动1 303 cm^-1均随压力增大而基本呈线性向高频方向移动，并在2.47 GPa附近发生过压凝固，这是一种平衡稳定态之外的亚稳态现象。另外推测正戊烷在高压下可能发生固－固相变，最后通过平衡的固液共存相确定了正戊烷的平衡凝固压力为(1.90±0.05) GPa。

Stability of n-Pentane under High Pressure

Raman scattering spectroscopy was used to investigate stability of n-pentane in Moissanite anvil cell from 0.07 GPa up to 4.77 GPa at ambient temperature. The result shows that CH₃ symmetric and asymmetric stretching vibration, CH₂ symmetric and asymmetric stretching vibration and －(CH₂)_n － in-phase twist mode at 2 877 cm^-1, 2 964 cm^-1, 2 856 cm^-1, 2 935 cm^-1 and 1 303 cm^-1, respectively, shifted to higher frequency according to quasi-linearity with pressure increase, and an abrupt visible change was taken place, indicating that it is a sort of phenomenon of freezing at overpressurization. In addition, a high-pressure transition phase may appear in crystallized n-pentane in the range of 2.84~4.77 GPa. The equilibrium freezing pressure of n-pentane is (1.90±0.05) GPa at 27 ℃ by measuring with the method of crystal-liquid coexistence.