Historical changes in the molecular model of asphaltene

This paper reviews the average molecular models of asphaltene proposed in past years, and introduces recent results of individual molecular structure analyses. The understanding of the asphaltene molecular structure has evolved as analytical techniques advance. In around 2016, modern mass spectrometry ended the controversy over whether island-type or archipelago-type molecules are correct, and clarified the diversity in chemical composition. Atomic force microscopy techniques can now determine individual molecular structures. The historical changes in our understanding of asphaltene are summarized in five stages (Asphaltene 1.0∼5.0).