Properties of high-pressure solvents for fullerenes

在高压下观察了C60在甲苯中的溶解现象。在此之前，对高压设备进行了一些改进，以使容器中的高压保持几个月，因为溶解度的平衡需要几天或几周的长时间。其中一个改进是选择热处理的铜作为垫片的材料，并以0.01 mm的精度切割它以适合高压气缸的气缸。观察到C60在甲苯中的两个溶解度(X)-压力(P)-温度(T)表面，表明C60在固相中存在相变。这些表面是在下列方程中绘制的：respectively.lnx+5.087-8.426x10^3(p/MPa)-15.385x10^&lt；-6&gt；(p/MPa)(high压力和低temperature)lnx-10.9612+943.881(T/K)+[261(T/K)-0.0724](p/MPa)(low压力和高温)使用正己烷。作为下一步的溶剂，还测定了C60的高压溶解度。它显示了表面的断裂，表明在高压下发生了相变，在甲苯中也出现了C60。相变后溶解度增加，但在甲苯中的溶解度降低。高压溶解度的这种差异表明，与饱和溶液共存的溶剂化固体的结构彼此不同。

Solubility phenomena of C60 in toluene was observed under high pressure. Before doing it, some improvements for high-pressure equipment have been done to keep the high pressure in the vessel for several months because the equilibration for the solubility takes a long time of several days or weeks. One of the improvements was done by selecting a heat-treated copper as a material for the gasket and by cutting it with an accuracy of 0.01 mm to fit it to the cylinder of the high-pressure cylinder.Two solubility (x in mole-fraction unit) -pressure (p)-temperature (T) surfaces were observed for C60 in toluene suggesting an phase transition in solid phase. These surfaces were drawn in the following equations, respectively.lnx+5.087-8.426x10^3(p/MPa)-15.385x10^<-6>(p/MPa)(high pressure and low temperature)lnx-10.9612+943.881(T/K)+[261(T/K)-0.0724](p/MPa)(low pressure and high temperature)Using hexane. as a solvent in the next step, high-pressure solubility of C60 was also measured. It showed a breaking of the surface suggesting a phase transition at a high pressure as well as C60 in toluene. The solubility increased after the phase transition though that in toluene decreased. Such difference in the high-pressure solubility suggests that the structure of solvated solids which coexist with saturated solutions differs from each other.