synthesis of 4-(trifluoromethyl) coumarins using nano sulfated-titania as solid acid catalyst under solvent-free conditions

nano sulfated titania was tested as solid acid heterogeneous catalyst for the synthesis of 4-(trifluoromethyl) coumarin and coumarin derivatives under solvent-free condition. factorial design evidenced a positive effect of reaction temperature, amount of catalyst, and solvents.  this nano-sized sulfated titania has been prepared by a sol-gel hydrothermal process. the prepared sulfated titania showed high catalytic activity in the synthesis of 4-(trifluoromethyl) coumarin and coumarin derivatives. this method is of great value because of its environmentally benign character, easy handling, high yields, convenient operation, and green. ft-ir studies show that the catalyst can be reused for acylation without loss of catalytic activity.