液体クロマトグラフィーによる石炭液化油アスファルテンのキャラクタリゼーション

抄録

A characterization method of coal-derived asphaltene has been studied by preparative scale reversed-phase liquid chromatography using ODS-silica gel as stationary phase and THF- methanol eluent system as mobile phase. Asphaltenes derived from Taiheiyo coal and Yallourn coal were separated stepwise into five fractions, Fl-5, using each 100 ml of 0, 10, 30, 50 and 100 v/v% of THF in methanol solution at a flow rate of 5ml/ min on the 10 i. d.×500mm column packed with ODS-silica gel (25-45μm). Each fraction was investigated in terms of elemental analysis, molecular weight determination, fa value and UV absorptivity. The molecular weight of the separated fractions increases as the fraction number increases according to the hydrophobicity of the fraction. The plot of H/C vs. fa in Fig. 1 shows that the asphaltene samples are separated according to the degree of ring condensation rather than the carbon number of side chains judging from the gradient of the slope and the distribution of H/C values. The relationship between molecular weight of the fraction and the absorptivity at 220 nm (K₁) or at 260 nm (K₂) is linear except for Fl of K₂, as shown in Fig. 2, which provides basic data for the characterization of asphaltenes by analytical scale HPLC determination using UV monitoring system.