费托蜡在五种有机溶剂中的溶解度测定及关联

Determination and correlation of the solubility of Fischer-Tropsch wax in five different organic solvents

研究采用动态法测定常压下费托蜡在正丁醇、乙酸丁酯、正辛烷、石油醚和甲苯溶剂体系中的溶解度。结果表明,费托蜡在5种有机溶剂中的溶解度均随温度升高而增大,且在不同溶剂中费托蜡的溶解度存在较大差异。采用Apelblat方程、多项式方程以及简化的二参数方程关联溶解度数据,关联结果良好,但Apelblat方程、多项式方程的拟合效果优于简化的二参数方程。此外,通过修正的Van’t Hoff方程计算,得到费托蜡在5种有机溶剂中的溶解焓Δ_(sol)H、溶解熵Δ_(sol)S和溶解吉布斯自由能Δ_(sol)G,结果表明费托蜡在5种有机溶剂中的溶解过程均为吸热、熵增的非自发过程。所得结果能够为费托蜡结晶工艺的开发提供重要的理论依据。

Solubilities of Fischer-Tropsch wax in organic solvents(n-butanol,butyl acetate,n-octane,petroleum ether and toluene)under atmospheric pressure were measured by a dynamic method.The results show that the solubilities of Fischer-Tropsch wax in the five organic solvents increase with temperature,and are of great difference in different solvents.The solubility data were well correlated by Apelblat equation,polynomial equation and simplified two-parameter equation,and better correlated by Apelblat equation and polynomial equation than by simplified two-parameter equation.In addition,the values of the dissolution enthalpyΔ_(sol)H,dissolution entropyΔ_(sol)S and dissolution Gibbs free energyΔ_(sol)G of Fischer-Tropsch wax in the five organic solvents were calculated by modified Van’t Hoff equation.The obtained values of these thermodynamic parameters show that the dissolution processes of Fischer-Tropsch wax in the five organic solvents are endothermic,entropic and non-spontaneous.The results obtained can provide an important theoretical basis for the development of Fischer-Tropsch wax crystallization processes.