N-substituted-5-methyl-2-piyrrolidones have been obtained by reductive amination of ethyl levulinate with amines in presence of H 2 as reducing agent under solvent free conditions. The process involves as a first step the formation of an imine intermediate followed by hydrogenation of the imine group and subsequent cyclization into pyrrolidone. Pt/TiO 2 with Pt crystal faces decorated with TiOx is a very active and chemoselective catalyst, being possible to achieve high conversion and selectivity to the corresponding N-substituted-5-methyl-2-pyrrolidones even when other groups susceptible of hydrogenation such as vinyl, carbonyl or cyano groups are present in the amine moiety. A kinetic study showed that the reaction controlling step is the formation of the imine intermediate. The rate of formation is enhanced by the presence of protonic acid sites generated on the support by hydrogen dissociation on the metal resulting in a true bifunctional catalyst for the reaction.

N-substituted furfuryl amines are an important class of compounds due to their pharmaceutical activities that can be produced by reductive amination of furfuraldehydes derived from biomass. With supported Pd nanoparticles it is possible to obtain high activities and selectivities for the production of secondary amines. CO adsorption monitored by IR show the importance of the Pd crystal size and crystal face on catalyst activity and selectivity. When using Pd on carbon the amount of unsaturated Pd sites is very much enhanced with the corresponding increase in selectivity. The role of carbon deposition on metal terraces on catalytic selectivity is discussed. The optimized catalyst has been successfully applied in the reductive amination of 5-hydroxymethylfurfural with different amines and ammonia as well as in the one-pot reductive amination starting from nitrobenzene instead of aniline, giving the different N-substituted-5-(hydroxymethyl)-2-furfuryl amines with excellent activity and selectivity.

N-substituted 5-methyl-2-pyrrolidones were prepared in a one-pot process starting from ethyl levulinate and nitro compounds in the presence of a nanosized Pt-based catalyst. Pt supported on TiO nanotubes (Pt/TiO -NT) catalyzed the synthesis of N-substituted 5-methyl-2-pyrrolidones through a cascade process involving the reduction of nitro compounds, formation of the intermediary imine, hydrogenation, and subsequent cyclization. A bifunctional metal-acid system was a suitable catalyst for the process. Pt supported on TiO showed lower catalytic activity than Pt/TiO -NT owing to the strong adsorption of nitro compounds during the first reaction step that poisoned the acidic sites and strongly decreased the rate of amination and cyclization. However, Pt/TiO -NT with milder acid sites was less affected by the adsorption of nitro compounds and the full cascade process could proceed. The results indicate that the prepared Pt/TiO -NT is a chemoselective and reusable catalyst that can be applied to the synthesis of a variety of N-substituted 5-methyl-2-pyrrolidones starting from nitro compounds with excellent yields in absence of an additional organic solvent under mild reaction conditions.

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During oxidative depolymerization of lignin in aqueous alkaline medium using molecular oxygen as oxidant, the highly functionalized primary phenolic monomers are not stable products, owing to various not fully identified secondary reaction mechanisms. However, better understanding of the mechanisms responsible for the instability of the main part of the products of interest derived from lignin is of much interest. Evaluation of their individual reactivities under oxidative conditions should significantly help to find a better way to valorize the lignin polymer and to maximize the yields of target value‐added products. Consequently, the main objective of this study is to assess the individual stabilities of some selected lignin‐based phenolic compounds, such as vanillin, vanillic acid, and acetovanillone, together with some other pure chemical compounds such as phenol and anisole to give an insight into the mechanisms responsible for the simultaneous formation and repolymerization of those products and the influence of the oxidation conditions. Various complementary strategies of stabilization are proposed, discussed, and applied for the oxidative depolymerization reactions of a technical lignin extracted from pinewood with a high content of β‐O‐4 interconnecting bonds to try to obtain enhanced yields of value‐added products.

More specifically, the catalyst can be successfully applied for different carbon-carbon (C-C) and carbon-heteroatom (C-N, C-O, C-S) bond forming reactions integrated in a cascade sequence. The activity of the organocatalyst has been compared with that of structurally related monofunctional and bifunctional catalysts.The most attractive features of this procedure are the high atom economy, the use of inexpensive starting materials as well as the use of an environmentally friendly catalyst that can be easily recovered thanks to its ionic liquid properties.