Benzimidazole
has several applications in different industries
but is used mainly in the pharmaceutical sector. Due to its high demand,
the production of benzimidazole by clean and green catalytic processes
has become important. In the present study, we have optimized a method
to achieve a one-pot synthesis of benzimidazole selectively over a
meso-cellular foam (MCF) supported bimetallic catalyst, Cu–Ni@MCF.
This catalyst provides active metal sites for hydrogenation of o-nitroaniline to o-phenylenediamine (OPDA)
as well as cyclization of OPDA into the final product, benzimidazole.
Along with the bifunctionality of the catalyst, the solvent consisting
of a mixture of dimethylformamide (DMF) and water (2:1) plays a significant
role in providing the in situ source of hydrogen and carbon dioxide
for both the hydrogenation and cyclization steps, respectively. o-Nitroaniline is converted into the final desired product
in 6 h at 180 °C and 800 rpm (for the lab reactor). Characterization
of the synthesized catalyst was done to understand its activity and
selectivity. The reaction mechanism and kinetics were established,
and the apparent activation energy was calculated. Optimization studies
were done to get the best results for the reaction. The non-noble-supported
nanometal catalyst aids in cutting down the cost of the overall system
and reduces the reaction period. It is a clean and green process.