Covalently Supported Sulfonic and Acetic Acids onto Polypyrrole Asgreen, Cheap and Recoverablesolid Acid Catalysts for the synthesis of 4H-pyrano[2,3-c]pyrazoles

Sulfonated polypyrrole nanospheres and polypyrrole N-functionalized acetic acid were synthesized. The catalytic efficiency of the prepared solid acid catalysts for the synthesis of 4Hpyrano[2,3-c] pyrazoles derivatives was evaluated and compared. The results showed that, regarding the time and yield of the products, the sulfonatedpolypyrrolenanospheres catalyst has better catalytic activity than polypyrrole N-functionalized acetic acid during first andsecond runs but shows a slight decline in its activityduring thethird run.