“…Recently, sulfonic acid functionalized imidazolium salts (SAFIS) have been prepared and characterized as a new group of acidic ionic liquids and applied as solvents, cata-lysts, and reagents in organic transformations for the preparation of bis(indolyl)methanes, 14 N-sulfonyl imines, 15 1-amidoalkyl-2-naphthols, 16 xanthene derivatives, 17 1-carbamatoalkyl-2-naphthols, 18 4,4′-(arylmethylene)bis(3-methyl-1-phenyl-1H-pyrazol-5-ol)s, 19 N-Boc-protected amines, 20 hexahydroquinolines, 21 nitroaromatic compounds, 22,23 1,2,4,5-tetrasubstituted imidazoles, 24 6-amino-4-(4-methoxyphenyl)-5-cyano-3-methyl-1-phenyl-1,4-dihydropyrano[2,3-c]pyrazoles, 25 benzylated aromatic compounds, 26 β-acetamido ketones, 27 benzimidazoles, 28 and amido-alkyl phenols. 29 Herein, we introduce 1,3-disulfonic acid imidazolium chloride ([Dsim]Cl), by simple reaction of imidazole (1 equiv) with chlorosulfonic acid (2 equiv) at room temperature (Scheme 1) as a sulfonic acid functionalized imidazolium salt (SAFIS) [14][15][16] and a highly efficient reagent for the sulfonation of aromatic compounds at 50 °C in aqueous medium.…”