Halogen-Free Room-Temperature Brønsted Acidic Ionic Liquid [Hmim]<sup>+</sup> HSO<sub>4</sub> <sup>−</sup> as a Recyclable Green “Dual Reagent” Catalysis for the Synthesis of Triarylmethanes (TRAM<scp>s</scp>)
halogen-free Brønstedacidicionicliquid methylimidazolium hydrogen sulfate ([Hmim]+ HSO4 −) acts as a very efficient catalyst for the one-pot, two-component Baeyer condensation of a variety of aromatic aldehydes with dimethyl or diethyl aniline at room temperature. This “green” reagent behaves as both catalyst and solvent; that is, it exhibits “dual-reagent catalysis.” The room-temperature acidicionic liquid