Study of Brazilian asphaltene aggregation by Nuclear Magnetic Resonance spectroscopy

Nuclear Magnetic Resonance experiments were used to study the relationship between the structural type (continental or archipelago) and aggregation properties of three different asphaltenes (asph_A, asph_B and asph_C). Diffusion-ordered NMR spectroscopy (DOSY) was applied to investigate the diffusion coefficients. The self-diffusion of the asphaltene aggregates was investigated in the concentration range of 0.01-10% of each asphaltene in deuterated toluene. Data obtained from 1H and 13C NMR indicate that asph_B has a predominantly continental type of structure. This contributes to different properties of aggregation. DOSY shows the presence of three aggregates, with three different diffusion coefficients, called nanoaggregate, microaggregate and macroaggregate.