(Elsevier, 2018-02) Godino Ojer, Marina; Pérez Cadenas, Agustín Francisco; Pérez Mayoral, María Elena; Martín Aranda, Rosa María
We report herein different series of new zero valent Cobalt nanocarbons, as doped and supported aerogels, able to efficiently catalyze the reaction of 2-amino-5-chlorobenzaldehyde and -ketoesters, via Friedländer reaction. The reaction works under solvent-free and mild conditions affording yields over 80% in only 30 min of reaction time. The catalysts could be reused almost during two consecutive cycles without almost any activity loss. A comparative study between supported and doped-carbon aerogels, as catalysts highly efficient in the reaction, has allowed to stablish the relationship between the catalyst structure and the catalytic performance. At this regard, different parameters such as carbonization temperature and surface chemistry on the aerogels under study have been also explored. As a result, although the carbon matrix is involved in the reaction, the Co(0) nanoparticles on the carbon surface are the predominant active catalytic species. Oxygen functionalities on the oxidized samples in the surroundings of Co(0) nanoparticles probably prevent the access of the reagents, notably decreasing their catalytic performance.
