关键词: 石油磺酸盐 , 活性组分 , 当量分布 , 界面张力 , 亲油基

Abstract: Active fractions were extracted from series petroleum sulfonates by extraction and back－extraction method，the equivalent weight distribution of them were analyzed by ESI－MS spectrum and the average equivalent weight could be calculated，as well as gas－phase osmotic method was conducted to determine the average relative molecule mass of their oleophylic groups which were obtained by desulfonation．The interfacial tension of oil／water system respectively consisted of series petroleum sulfonates or their active fractions were measured by rotated dropping method．The results show that the difference of the equivalent weight distribution mainly existed in the low and high equivalent weight section，and the one which has properly hydrophile－lipophile balance for the complementation of molecule structure benefiting from broad equivalent molecule weight distribution，its oil／water system can obtain the ultralow interfacial tension．

Key words: Petroleum sulfonates , Active fractions , Equivalent weight distribution , Interfacial tension , Oleophylic groups