Green Synthesized AgNPs Embedded in COF: An Efficient Catalyst for the Synthesis of 2-Oxazolidinones and alpha-Alkylidene Cyclic Carbonates via CO2 fixation

The synthesis of important organic chemicals through sustainable and green methods is always demanding for the scientific community. Fixation of carbon dioxide for this purpose is very attractive as CO2 is non-toxic, easily available, naturally abundant, recyclable, non-flammable and an inexpensive C1 resource, and also the concentration of CO2 (most responsible greenhouse gas) is reduced. This article demonstrates the synthesis of silver nanoparticles (AgNPs) by an eco-friendly method and incorporation of the particles into a covalent organic framework in order to obtain a sustainable heterogeneous catalyst, AgN@COF. The catalyst has been characterized in detail by FT-IR,UV-Vis. spectro-scopy, FE-SEM, TEM, EDAX, XPS, PXRD, ICP-AES, TG-DTA and N-2 absorption-desorption studies. The synthesized catalyst is able to fix CO2 to terminal propargylic amine and propargylic alcohol for the production of 2-oxazolidinones and alpha-alkylidene cyclic carbonates, respectively, through two different catalytic pathways. In both catalytic protocols, one atmospheric carbon dioxide was used. Production of alpha-alkylidene cyclic carbonates occurred at room temperature and solvent-free condition, and 2-oxazolidinones were obtained under mild reaction conditions. Moreover, the catalyst is recyclable and reusable. Its catalytic efficacy was preserved even after the use of six consecutive catalytic cycles.