Results of a study of the reaction products of asphaltene sulfonation with sulfuric acid in various temperature and time ranges have been described. The maximum sulfur content in sulfonated cation exchangers at an asphaltene sulfonation temperature of 100 and 120 degrees C and a reaction time of 2 h has been determined. The maximum static exchange capacity of 4.3 meq/g has been found for the products of sulfonation with a sulfuric acid-oleum mixture. The asphaltene-based strongly acidic sulfocationite has been tested in the 2,2-dimethyl-1,3-dioxolane synthesis reaction.