Microwave Assisted Reactions of Natural Oils: Transesterification and Hydroformylation/Isomerization as Tools for High Value Compounds

A comparative study on the transesterification of natural oils obtained from Calophyllum inophyllum seeds was carried out using homogeneous (NaOH/MeOH) or heterogeneous catalysts, with conventional heating and under microwave irradiation. The results show that the microwave-assisted reaction using heterogeneous catalysts, obtained from renewable sources (rice husk and egg shell ashes), constitutes an energetically sustainable approach for transesterification. In order to obtain value-added products from natural oils, rhodium/monophosphite catalysts were applied to the hydroformylation of methyl oleate, also under conventional heating or microwave irradiation. Using conventional heating conditions (T = 80°C; Psyngas = 30 bar), high catalytic activity was observed with 98% chemoselectivity for aldehydes, while under microwave irradiation, using a CEM® Discover system equipped with syngas addition kit, high conversions were observed under mild reaction conditions (T = 60°C; Psyngas = 10 bar), mainly with formation of isomerization products.