ABSTRACT
The early method for the treatment of deasphaltened crude oil with sulfuric acid usually produced a precipitate (Fig. 3.11) that consisted of material that had been converted to a polar fraction by interaction of the asphaltic constituents with the sulfuric acid. It is nevertheless possible that some of the acid-precipitated material originated as asphaltenes that were incompletely precipitated the naphtha, because the addition of only 20 volumes of solvent to heavy feedstocks is not sufficient to completely precipitate asphaltene material (see Section 4.1).
