反气相色谱法研究煤直接液化残渣经分级提取前后的表面性质变化

采用反气相色谱法（IGC）分别对煤直接液化残渣（DCLR）脱灰处理后不溶物、正己烷不溶物、甲苯不溶物、四氢呋喃不溶物的表面性质进行表征。基于非极性探针净保留体积V_n分别采用Dorris-Gray方法和Schultz方法得到表面色散自由能，基于极性探针V_n得到吸附焓△H^sp，并通过△H^sp作图计算得到酸常数K_a和碱常数K_b。结果表明，经溶剂分级提取后表面色散自由能、K_a和K_b均发生明显变化。而DCLR呈现两性偏碱性这一特征并未随分级提取发生改变。IGC作为一种动力学吸附技术，可快速准确表征DCLR在经分级提取过程中表面性质的变化，相同温度下应用Dorris-Gray方法得到DCLR表面色散自由能略高于Schultz方法。

Determination of surface properties of direct coal liquefaction residue before and after solvent extraction by inverse gas chromatography

Direct coal liquefaction residue (DCLR) is deashed by hydrochloric acid and hydrofluoric acid to obtain ACLR. The ACLR was extracted with n-hexane, toluene and tetrahydrofuran to obtain n-hexane insoluble matter (HCLR), toluene insoluble matter (TCLR), tetrahydrofuran insoluble (FCLR). The surface properties of ACLR, HCLR, TCLR and FCLR were characterized by inverse gas chromatography (IGC). Based on net residual volume V_n of the non-polar probe, surface dispersion free energy were calculated by Dorris-Gray and Schultz method respectively. The adsorption enthalpy △H^sp of the polar probe on surface of the 4 insoluble solids was obtained by V_n of the polar probe, and the acid constant K_a and the base constant K_b of the 4 insoluble solids were calculated by △H^sp. The results show that the surface dispersion free energy of ACLR are obviously changed after solvent extraction, and the dispersion free energy on surface of the 4 insoluble solids is decreasing from 60 to 100℃. By K_b/K_a> 1 and △H^sp analysis, 4 insoluble solids surfaces are both amphoteric and the alkaline effect is stronger than that of the acid effect. As a kinetic adsorption technique, IGC can quickly and accurately characterize change of surface properties of DCLR during fractionated extraction. At the same temperature the surface dispersion free energy obtained by the Dorris-Gray method is slightly higher than that by the Schultz method.