CuNi bimetallic nanocatalyst enables sustainable direct carboxylation reactions

• Published in: Molecular catalysis 2022-09, Vol.530, p.112620, Article 112620
• Main Authors: Choudhary, Neha, Abdelgaid, Mona, Mpourmpakis, Giannis, Mobin, Shaikh M.
• Format: Article
• Language: English
• Subjects: Bimetallic nanocatalyst; Carboxylation reaction; Recyclable catalyst; Solvent-free reaction
• ISSN: 2468-8231; 2468-8231
• DOI: 10.1016/j.mcat.2022.112620

•Direct carboxylation of arenes using bimetallic CuNi nanocatalyst was explored.•Solvent-free, additive-free and activator-free conditions were involved.•Formic acid was used as carboxylating agent.•CuNi nanocatalyst is magnetically separable and recyclable.•The carboxylation mechanism involves C-H bond activation of benzene and formic acid. Herein, we combine catalyst synthesis, characterization, catalytic experiments, and theory to investigate the bimetallic CuNi-11 nanocatalyst for direct carboxylation of arenes. Catalytic experiments reveal that the CuNi-11 shows an excellent yield and a higher benzene conversion compared to monometallic Cu and Ni nanocatalysts. The bimetallic CuNi-11 nanocatalyst exhibits a high surface area of 58.993 m2/g with excellent reusability (up to 6 cycles) and the carboxylation reaction is an activator-, additive- and solvent-free taking place under mild conditions. Catalytic experiments are complemented by Density Functional Theory (DFT) calculations demonstrating a plausible mechanistic pathway involving C-H bond activation of benzene and formic acid. The benzoic acid and H2 formation with the benzene C–H activation being the rate-determining step. Overall, our work contributes to introducing sustainable and environmentally friendly carboxylation routes of arenes with a new mechanistic approach. Herein, we report bimetallic (CuNi) nanocatalyst for direct carboxylation of certain aromatic compounds. The mechanistic insights reveal individual metal in bimetallic system plays crucial roles in achieving corresponding acids. The mechanistic pathway involves C-H bond activation of both benzene and formic acid on the metal surface followed by the formation of benzoic acid and H2. [Display omitted]