Nitrogen-functionalized carbon nanotubes as a basic catalyst for biomass conversion reactions

Biomass conversion to transportation fuels and chemicals is a growing field of research due to the depletion of fossil fuels feedstock. New catalysts, optimized for carbohydrates conversion, need to be developed. In this context, basic heterogeneous catalysts will play a major role for dehydration, hydrolysis, (trans)esterification, aldol condensation, alkylation or isomerization reactions for example. In contrast to existing basic heterogeneous catalysts, MWCNTs-based catalysts are chemically stable (no leaching) and relatively easy to tailor on a nano- and macro-level (controlled porosity). Therefore, nitrogen-functionalized multiwalled carbon nanotubes (N-MWCNTs) appear to be a promising basic catalyst and catalyst support [1,2]. Unfortunately, the nitrogen concentration, its location in/on the nanotube and the nature of the formed N-containing functional groups are difficult to control by common synthesis techniques like by catalytic chemical vapor deposition (CCVD) or by post-treatments [3]. In addition, it is still unclear which functional groups are required to reach high catalytic activities. Thus, we synthesized N-MWCNTs catalysts by grafting desired N-containing molecules on the MWCNTs’ surface. In order to avoid the drawbacks of the traditional SOCl2 route, a new procedure has been designed. The obtained catalysts have been tested in the transesterification of glyceryl tributyrate, as a model triglyceride for biodiesel synthesi

N-functionalized carbon nanotubes as solid basic catalysts for biomass conversion

In the view of declining fossil fuel energy resources and rising oil prices, it is necessary to develop new ways to satisfy the energy needs and the production of chemicals. An alternative route is the use of biomass, in fact, it can serve as a sustainable source of renewable fuels and high value chemicals and materials [1-2]. Thus new catalysts need to be developed. In particular basic catalysts will play an important role for many reactions involving biomass transformation such as transesterification, dehydration, aldol condensation, or isomerization reactions, for example [3]. Nitrogen-containing carbon nanotubes (N-MWCNT) appear to be a promising basic catalyst [4]. In fact, in contrast to the existing heterogeneous basic catalysts (such as hydrotalcite, MgO, CaO) they are chemically stable and they do not suffer of problem of leaching. In this work we developed a new route to synthesize N-MWCNTs by grafting different ammines (diethyl-ethylamine, ethylamine and pyrrolidine) on the surface of the MWCNTs. Thus we investigated the potential use of N-MWCNTs as solid catalysts in the transesterification of triglycerides, model reaction for basic catalysts. In particular we study the influence of the basicity of the different amines on the catalytic activity and the stability of the catalysts after recycling reactions

Nanostructured Polymer Derived Ceramics : Design, Processing and Properties

International audienc

Amino-functionalized carbon nanotubes as solid basic catalysts for the transesterification of triglycerides

Multiwalled carbon nanotubes grafted with various amino groups show high activity and stability when used as basic catalysts for the transesterification of triglycerides

Polymer Derived nanostructured non oxide porous Ceramics

International audienc

Nitrogen-functionalized carbon nanotubes as a basic catalyst for biomass conversion reactions

Biomass conversion to transportation fuels and chemicals is a growing field of research due to the depletion of fossil fuels feedstock. New catalysts, optimized for carbohydrates conversion, need to be developed. In this context, basic heterogeneous catalysts will play a major role for dehydration, hydrolysis, (trans)esterification, aldol condensation, alkylation or isomerization reactions for example. In contrast to existing basic heterogeneous catalysts, MWCNTs-based catalysts are chemically stable (no leaching) and relatively easy to tailor on a nano- and macro-level (controlled porosity). Therefore, nitrogen-functionalized multiwalled carbon nanotubes (N-MWCNTs) appear to be a promising basic catalyst and catalyst support [1,2]. Unfortunately, the nitrogen concentration, its location in/on the nanotube and the nature of the formed N-containing functional groups are difficult to control by common synthesis techniques like by catalytic chemical vapor deposition (CCVD) or by post-treatments [3]. In addition, it is still unclear which functional groups are required to reach high catalytic activities. Thus, we synthesized N-MWCNTs catalysts by grafting desired N-containing molecules on the MWCNTs’ surface. In order to avoid the drawbacks of the traditional SOCl2 route, a new procedure has been designed. The obtained catalysts have been tested in the transesterification of glyceryl tributyrate, as a model triglyceride for biodiesel synthesi

Préparation de céramiques nanostructurées de type nitrure à porosité contrôlée par une approche moléculaire

International audienc

Defect-Mediated Functionalization of Carbon Nanotubes as a Route to Design Single-Site Basic Heterogeneous Catalysts for Biomass Conversion

Aktive Zentren wurden direkt durch einen elektrophilen Angriff an Strukturdefekten von Kohlenstoffnanoröhren eingeführt (siehe Bild). Dieses Syntheseverfahren ist schneller und effizienter als andere und kann Heterogenkatalysatoren liefern, die einstellbare aktive Zentren enthalten. Solche Katalysatoren auf der Basis von Kohlenstoffnanoröhren verfügen über ein großes Potenzial bei der Umwandlung von Biomasse in der Flüssigphase

Elaboration de céramiques de carbonitrure de silicium et de bore (SiBCN) à porosité contrôlée par la voie « polymères précéramiques

International audienc

Transesterification of Triglycerides Using Nitrogen-Functionalized Carbon Nanotubes

Nitrogen-functionalized carbon nanotubes were synthesized by grafting amino groups to the surface of the nanotubes. The nanotubes exhibited promising results in the base-catalyzed liquid phase transesterification of glyceryl tributyrate with methanol, which is a model reaction for the production of biodiesel. The concentration of the active sites and the reaction parameters, such as temperature and glyceryl tributyrate to methanol ratio, were shown to significantly affect catalytic performance. The grafting technique employed allowed for design and control of the active sites. As a consequence, it was possible to design a nitrogen-functionalized carbon nanotube catalyst with a few strong, basic groups. This might be of interest for carbohydrate conversion reactions where strong basic sites are required but the pH of the solution should remain mild to avoid the degradation of the reactants and/or products