Liquid‐phase NMR of asphaltenes

The present review focuses on the most recent advances in liquid‐phase NMR of asphaltenes, leaving apart an overwhelming amount of publications dealing with solid‐state NMR investigations in this field. Owing to the complexity of the coal‐derived products, and in particular, asphaltenes, their 1H and 13C NMR spectra consist of a number of overlapping signals belonging to different hydrocarbon types. Comprehensive studies of asphaltenes by means of NMR reveal the characteristic functional groups of their fractions together with the spectral regions in which they resonate. NMR studies of asphaltenes provide a straightforward guideline for their chemical composition and that of the related coal‐derived products.