Perlite: an inexpensive natural support for heterogenization of HBF4
Nano-perlite-fluoroboric acid (n-PeFBA) has been synthesized by immobilization of HBF4 on perlite to produce an efficient green heterogeneous reusable solid acid catalyst. The catalyst was characterized by (FE-SEM, EDX, BET and BJH). This catalyst was employed to prepare biologically important 2,4,5-trisubstituted and 1,2,4,5-tetrasubstituted imidazoles with high yields and selectivities. Advantages of solid acid include: low cost, facile handling, simple preparation, high stability, reusability and low toxicity. The catalyst could be recovered and reused for several runs without deterioration in catalytic activity.