catalysts based on Al2O3, supercritical carbon dioxide not only acts as a good solvent for the reaction of aromatic and aliphaticaldehydes with 1-nitroalkanes but, most importantly, it also allows the selectivity to be tuned between the competitive formation of beta-nitroalcohols and nitroalkenes (from the Henry reaction and the nitroaldol condensation, respectively). In particular, when the pressure