فهرس المقالات N-(4-sulfonic acid) butyl triethylammonium hydrogen sulfate ([TEBSA][HSO4]) حرية الوصول المقاله صفحة الملخص نص كامل 1 - Brønsted acidic ionic liquid as the efficient and reusable catalyst for synthesis of coumarins via Pechmann condensation under solvent-free conditions Abdol Reza Hajipour Nafisehsadat Sheikhan Mohammad Ali Alaei Amin Zarei