Abstract: An investigation of selecting less poisonous dewaxing solvent (butanone/toluene) to substitute the conventional dewaxing solvent (acetone/benzene/toluene), which is more volatile and poisonous, in the determination of lubricating oil potential content (RIPP9-90) was carried out. A suitable proportion of butanone to toluene was obtained based on the variation of dewaxed oil yield with the mixed solvent composition. The dewaxing processes of VGO samples from various crude oils using this less poisonous solvent and the conventional one were conducted and qualities of these obtained dewaxed oil samples were compared. It was found that their properties and compositions (by mass spectrometry) were very close. Therefore, in the determination of lubricating oil potential content (RIPP9-90), the conventional dewaxing solvent could be substituted by this less poisonous one with butanone/toluene volume ratio of 60:40.

Key words: potential content of lubricating oil, dewaxing, wax content, mass spectrometry composition