The copper nanoparticles catalysed reduction of substituted nitrobenzenes: effect of nanoparticle stabilizers

Copper nanoparticles are prepared and size characterized using FESEM and HRTEM. Poly ethylene glycol (PEG), carboxy methyl cellulose (CMC) and poly N vinyl pyrrolidone (PVP) are used as the nanoparticle stabilizers. The reduction reactions of fourteen differently aromatic ring substituted nitro benzenes are carried out with NaBH₄ solution catalyzed by the copper nanoparticles with PEG, CMC and PVP as stabilizers. Using time variance UV absorbance spectra, the progress of the reactions are kinetically monitored, the parameters such as product % yield, time of reaction and rate coefficient values are determined and used for deducing the comparative catalytic efficiency. The copper nanoparticles as synthesized using biopolymers such as PEG and CMC produce better reaction parameters than the PVP stabilized Cu nps. Also the effect of substituents in the aromatic ring of the nitro compounds reveals that −I substituents containing nitro compounds are better catalyzed than the +I substituents. The sizes of the three Cu nps are found to be 6, 12 and 15 nm corresponding to PEG, CMC and PVP stabilizers respectively.