A novel heterogeneous solid acid catalyst has been prepared by covalent grafting of chlorosulphonic acid on amino-functionalized cellulose (Cell–Pr-NHSO3H).
TiO2-coated magnetite nanoparticles-supported sulfonic acid (nano-Fe3O4–TiO2–SO3H (n-FTSA)) is synthesized by the immobilization of –SO3H groups on the surface of nano-Fe3O4–TiO2.
The strong interaction of higher transition metal oxides with inorganic non-metals can be promising for generating highly acidic three-dimensional materials by design.
BF3/nano-sawdust was used as a readily available, inexpensive, biodegradable and environmentally benign heterogeneous solid acid catalyst for the one-pot cascade synthesis of highly functionalized dihydro-2-oxypyrroles.