Investigation of the catalytic activity of metallic copper and copper dispersed SiO2 for the reductive acetylation of aromatic nitro compounds

• Published in: Research on chemical intermediates Vol. 48; no. 5; pp. 1939 - 1952
• Main Authors: Govindaraj, Devi, Gopal, Buvaneswari
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 2022; Springer Nature B.V
• Subjects: Acetylation; Aluminum oxide; Aniline; Aromatic compounds; Catalysis; Catalysts; Catalytic activity; Chemistry; Chemistry and Materials Science; Conversion; Copper; Hydroxyapatite; Inorganic Chemistry; Nitro compounds; Nitrobenzene; Physical Chemistry; Silicon dioxide; Titanium dioxide; Nitroarenes; Copper; Arylacetamides; Catalyst; Catalyst support
• ISSN: 0922-6168; 1568-5675
• DOI: 10.1007/s11164-022-04703-y

N -Arylacetamides such as acetaminophen are important systems in medicinal chemistry. Reductive acetylation of nitroarenes is noted to be an efficient route for their preparation. Protocols were developed for one-pot reductive acetylation of nitroarenes in the presence of various catalysts under varied conditions. Current work studied the catalytic effect of metallic copper and supported copper systems towards the reductive acetylation of nitroarenes under mild condition. The influence of the supporting materials such as SiO 2 , Al 2 O 3 , TiO 2 and HAp (hydroxyapatite) was studied by comparing the activity of Cu/SiO 2 with that of Cu/TiO 2 , Cu/Al 2 O 3 and Cu/HAp. Cu/SiO 2 system emerged out as an efficient catalyst. In the first part of the reaction of reduction of nitrobenzene to aniline, both 4 wt% Cu–Al 2 O 3 and 4 wt% Cu–HAp lead to partial conversion till the formation of azoxybenzene, whereas 4 wt% Cu–TiO 2 showed 31% conversion of aniline. However, with 4 wt% Cu–SiO 2 , 100% conversion of aniline was achieved. Acetylation of the system afforded 97% yield of N -phenylacetamide. The activity of the catalyst was also tested for selected nitroarenes. Characterization by powder XRD, XPS, TEM, BET measurements, TPR study assisted in demonstrating the efficacy of SiO 2 -supported Cu.