Synthesis of green solvents from bio-based lactones using heterogeneous copper catalysts

In this paper, the synthesis of green solvents N-alkyl-pyrrolidinones starting from gamma-valerolactone using non -noble, supported copper catalysts is proposed. The reaction setup has been improved to limit both harsh con-ditions and auxiliaries and to avoid any catalyst pretreatment or a too high hydrogen pressure use. A CuO/Al2O3 catalyst with a high dispersion of the metal phase combined with a low Cu nanoparticle size proved to be the best for the process. The catalytic system has proven to be suitable for other lactones such as gamma-butyrolactone, gamma-caprolactone, epsilon-caprolactone and dihydrocoumarin.