In this investigation Potassium iron zirconium phosphate was used as a mild, efficient and reusable solid acid catalyst for the Friedel–Crafts alkylation of various arenes with benzyl bromide under solvent-free conditions. Also zirconium hydrogen sulfate as a mild solid acid catalyst was applied for the preparation of ?-amino nitriles from condensation of aldehydes or ketones with aniline and trimethylsilylcyanide under solvent-free conditions at room temperature. Br?nsted acidic ionic liquids were designed to replace traditional mineral liquid acids in chemical procedures. In this investigation N -(4-sulfonic acid) butyl triethyl ammonium hydrogen sulfate ([TEBSA][HSO 4 ]) was synthesized and used as an efficient and reusable catalyst for the synthesis of some organic compounds. A convenient, mild and efficient procedure was reported for one pot three-component synthesis of amidoalkyl naphthols derivatives from various aryl aldehydes, 2-naphthol and different amides in the presence of [TEBSA][HSO 4 ] under solvent-free conditions at 120 ?C. 14-aryl or alkyl-14H-dibenzo[a,j]xanthenes were prepared from one-pot condensation of aldehydes with 2-naphthol using catalytic amount of Br?nsted acidic ionic liquid under thermal solvent-free conditions. [TEBSA][HSO 4 ] as effective catalyst was applied for the preparation of pyrimidinone derivatives from the reaction of aromatic aldehydes with cyclopentanone and urea or thiourea under thermal solvent-free conditions. Finally [TEBSA][HSO 4 ] catalyzed the Pechmann condensation of various phenols with different ?-ketoesters leading to the formation of coumarins under solvent-free conditions.
