An efficient and green procedure for the synthesis of 2,4,5-trisubstituted imidazoles with various aldehydes using a catalytic amount of 1-methylimidazolium hydrogenesulfate as an active and low cost Brönsted acidic room temperature ionic liquid has been developed. The ionic liquid was easily separated from the reaction mixture and was recycled five times without any loss in activity.Key words: ionic liquid, 2,4,5-trisubstituted imidazoles, [Hmim]HSO4, aldehyde, benzil.
Nano-perlite-fluoroboric acid (n-PeFBA) has been synthesized by immobilization of HBF4 on perlite as a natural and cheap support to produce an efficient green heterogeneous reusable solid acid catalyst.