【摘要】 本文采用分子动力学(MD)方法对超临界甲醇体系结构性质和动力学性质进行了模拟研究.结果表明,在超临界条件下甲醇体系因密度涨落存在分子聚集现象,且在低密度区域更明显.与常温常压条件下相比甲醇分子间的氢键作用明显减弱,结构变得松散,分子极性大大降低,自扩散系数上升了十几甚至几百倍.随着压强的增大,甲醇分子间的氢键作用增强,扩散系数减小;随着温度的升高,甲醇分子间的氢键作用减弱,自扩散系数增大,且在接近临界压力时,自扩散系数随温度的变化幅度更大.更多还原

【Abstract】 The structure and diffusion behavior of methanol at supercritical states are invesitigated by molecular dynamics simulation. Under supercritical conditions, the methanol system has aggregation phenomenon and even more evident at low-density region due to density fluctuations. The hydrogen bond interaction significantly weakens, the molecular polarity greatly reduces whereas the self-diffusion coefficient of methanol increases from ten to several hurdred times in supercritical conditions compare with ambient conditions. With the increase of pressure, the hydrogen bond interaction between supcritical methanol molecules increases, while self-diffusion coefficients decrease. With the increase of temperature, the hydrogen bond interaction between supercritical methanol molecules decreases, while self-diffusion coefficients increase and more obvious near the critical pressure.更多还原