Advanced Cobalt Nanocatalyst on Covalently Functionalized Halloysite for Alkoxy- and Aminocarbonylations

Abstract

Herein, we report the design of a bifunctional nanocatalyst comprising cobalt nanoparticles (CoNPs) and covalently functionalized halloysite nanotubes with peralkylguanidine moieties (HAL-PAG) for alkoxy- and aminocarbonylation processes mediated via dual catalysis. The nano-tubular morphology of naturally occurring halloysite, combined with peralkylguanidine functionalization, promotes efficient nanoparticle distribution on the support, avoiding agglomeration. A full characterization of the innovative nanomaterials confirms both the successful immobilization and the chemical environment of the CoNPs. Under optimized conditions, the CoNPs@HAL-PAG catalyst enables the alkoxy and amino-carbonylation of iodoarenes to the corresponding esters and amides, respectively, in high yields (up to 80%), significantly improved in comparison with the non-functionalized CoNPs@HAL catalytic material. CoNPs@HAL-PAG exhibits broad substrate scope across various aryl iodides, alcohols, and amines, including the synthesis of the blockbuster drug benzocaine. To the best of our knowledge, this represents one of the first examples of supported dual systems, encompassing both peralkylguanidine as a strong proton acceptor and non-noble metal-based nanoparticles applied to the alkoxy- and aminocarbonylations of aryl halides. This system offers a robust and recyclable catalyst for the sustainable synthesis of aryl esters and amides.