Silica-supported bismuth(III) chloride as a new recyclable heterogeneous catalyst for the Paal–Knorr pyrrole synthesis

Silica-supported bismuth(III) chloride (BiCl3/SiO2) acts as as a highly efficient heterogeneous Lewis acid catalyst for the Paal–Knorr pyrrole synthesis in hexane at room temperature. The catalyst exhibited remarkable reusable activity and higher catalytic performance than homogeneous BiCl3. A plausible mechanism for the catalytic action of BiCl3/SiO2 has been introduced.