Use of clay supported phosphoric acid as an efficient, recyclable and heterogeneouscatalyst for the synthesis of xanthenes

Ammonium hydrogen phosphate based ionic liquid immobilized on Na+–montmorillonite (AHP@MMT) was prepared via anchoring ammonium hydrogen phosphate propyl triethoxysilane onto sodium montmorillonite by covalent bonds. The synthesized catalyst was characterized by FT-IR and SEM techniques and the catalytic activity of this novel catalyst was tested for the synthesis of xanthene derivatives. High yields of the products and simple workup and separation of them, easy separation and recovery of catalyst, solvent free conditions and use of an inexpensive catalyst are some of advantages of our procedure. Also this catalyst can be reused several times without loss of its catalytic activity.

Keywords:

Immobilized ionic liquid , ammonium hydrogen phosphate , xanthenes , solid acid catalyst