- Continuous flow synthesis of amines from the cascade reactions of nitriles and carbonyl-containing compounds promoted by Pt-modified titania catalysts
-
The effective design of an active and stable catalytic system was performed by a simple modification of a commercial titania with a low platinum loading. The prepared material was fully characterized by XRD, XPS, N2 adsorption-desorption measurements, ICP-MS, TEM and SEM analyses. Such techniques corroborated the successful incorporation of Pt onto the titania surface, without affecting its original structure, morphology and chemical nature. The obtained TiO2-Pt catalyst was effectively applied in several continuous flow reactions between nitriles and carbonyl containing compounds for amine preparation. Remarkably, conversion of levulinic acid, a biomass derived molecule, was achieved with outstanding conversion (87%) and selectivity (80%) to 1-ethyl-5-methylpyrrolidin-2-one. The catalytic system demonstrated a high stability through 120 min of reaction. Moreover, the effect of the nitrile was investigated by performing the reaction with benzonitrile and ethylcyanoacetate. The TiO2-Pt catalyst was also tested in the conversion of benzaldehyde, displaying remarkable results. The influence of substitution in the aromatic ring was investigated using p-nitro-benzaldehyde and p-chloro-benzaldehyde.
- Altu?, Cevher,Mu?oz-Batista, Mario J.,Rodríguez-Padrón, Daily,Balu, Alina M.,Romero, Antonio A.,Luque, Rafael
-
-
Read Online
- Simplifying levulinic acid conversion towards a sustainable biomass valorisation
-
The demand for sustainable and robust catalysts for the valorisation of biomass is strictly related to the more and more pressing request to not only replace petroleum fuels with eco-friendly alternatives, but also to produce added value chemicals. In this context, the use of noble metals is not practically and economically sustainable and more abundant and stable alternatives are needed. In this contribution we have prepared and tested metal transition based catalysts (namely Ni3N and Ni nanoparticles) for the hydroconversion of levulinic acid (LA) as a model reaction. LA is useful also to produce valuable N-substituted pyrrolidones. Nanoparticles were prepared via a greener synthesis, using urea and metal salts, and have an average diameter of ~30 nm (as ascertained by XRD and TEM studies). The main product of the levulinic acid hydroconversion was 1-ethyl-5-methylpyrrolidin-2-one. While this product was always the preferred one when Ni was used, Ni3N favoured the formation of the main product only in a shorter reaction time (below 1 h) with very high selectivity (up to 55% conversion), while a secondary product was formed in a longer time. The stability of the catalysts was also tested. To the best of our knowledge this is the first time that such a reaction is tested using transition metals and metal nitrides, with very promising results.
- Defilippi, Chiara,Rodríguez-Padrón, Daily,Luque, Rafael,Giordano, Cristina
-
p. 2929 - 2934
(2020/06/17)
-