Oxidative Functionalization of Asphaltenes from Heavy Crude Oil

Sulfuric and nitric acids were used to functionalize asphaltenes isolated from heavy crude oil by treatment with heptane or hexamethyldisiloxane. The elemental composition of the asphaltenes was analyzed and their functional groups before and after the modification were identified. It was shown that the content of heteroatoms in the modified asphaltenes increases. Carbonyl, carboxyl, sulfonic, and nitro groups appear in the asphaltenes with the content dependent on the type of a modifier used and on the prehistory of how they were obtained.