Pd on thermo-responsive composite of silica-coated carbon nanotube and 1-vinyl-3-butylimidazolium-based ionic liquid copolymers as an efficient catalyst for hydrogenation of nitro compounds

Abstract

In this work, an ionic liquid-containing thermo-responsive heterogeneous catalyst with utility for promoting hydrogenation of nitro-compounds in aqueous media is developed. To prepare the catalyst, silica-coated carbon nanotubes were synthesized and vinyl-functionalized. The resulted compound was then polymerized with 1-viny-3-butylimidazolium bromide and N-isopropylacrylamide. The obtained ionic liquid-containing thermo-responsive composite was palladated via wet-impregnation method to give the final catalyst. Study of the performance of the catalyst confirmed high catalytic activity of the catalyst at temperature above the lower critical solution temperature. Furthermore, the catalyst was highly recyclable and showed negligible Pd leaching upon recycling. Broad substrate scope and selectivity of the catalyst towards reduction of nitro functionality were also confirmed. Furthermore, hot filtration test implied the heterogeneous nature of the catalysis. The comparison of the activity of Pd/CNT-P with some control catalysts approved the importance of hybridization of P and CNT and the presence of ionic liquid for the catalytic activity.

Ionothermal synthesis of magnetic N-doped porous carbon to immobilize Pd nanoparticles: An efficient heterogeneous catalyst for reduction of nitroaromatic compounds

“…Hence, metal-based heterogeneous and homogeneous catalysts have extensively been applied for reduction reactions of nitroaromatic compounds [14,15]. Till now, different kinds of heterogeneous catalysts utilizing noble metals such as Pd, Au, Pt, and Rh, as well as non-noble metal catalysts like Cu, Ni, Fe, and Co, have been reported to the direct reduction reaction of nitroaromatic compounds [16][17][18][19][20][21].…”