resumo
Useful bio-products are obtainable via the catalytic conversion of biomass or derived intermediates as renewable carbon sources. In particular, furanic ethers and levulinate esters (denoted bioEs) have wide application profiles and can be synthesised via acid-catalysed reactions of intermediates such as fructose, 5-hydroxymethyl-2-furaldehyde (HMF) and furfuryl alcohol (FA) with ethanol. Solid acid catalysts are preferred for producing the bioEs with environmental benefits. Furthermore, the versatility of the catalyst in obtaining the bioEs from different intermediates is attractive for process economics, and in the case of porous catalysts, large pore sizes can be beneficial for operating in the kinetic regime. Carbon-based materials are attractive acid catalysts due to their modifiable surface, e.g. with relatively strong sulfonic acid groups (SO3H). Considering these aspects, here, we report the preparation of mesoporous (SO3H)-functionalised-carbon/silica (C/S) composites with large pores and high amounts of acid sites (up to 2.3 mmol g(-1)), and their application as versatile solid acid catalysts for producing bioEs from fructose, HMF and FA. The mesoporous composites were prepared by activation of an organic compound deposited on the ordered mesoporous silicas MCF (mesostructured cellular foam) and SBA-15, where the organic compound (p-toluenesulfonic acid) acted simultaneously as the carbon and SO3H source. The atomic-level characterisation of the acid nature and strengths was performed by P-31 solid-state NMR studies of an adsorbed base probe, in combination with FT-IR and XPS. Comparative catalytic studies showed that the C/S composites are interesting catalysts for obtaining bioEs in high yields, in comparison with classical solid acid catalysts such as sulfonic acid resin Amberlyst (TM)-15 and nanocrystalline (large pore) zeolite H-beta.
palavras-chave
BEARING SULFONIC-ACID; ETHYL LEVULINATE; AMORPHOUS-CARBON; FURFURYL ALCOHOL; LIQUID FUELS; CONVERSION; BIOMASS; FRUCTOSE; BIODIESEL; CHEMICALS
categoria
Chemistry; Science & Technology - Other Topics
autores
Russo, PA; Antunes, MM; Neves, P; Wiper, PV; Fazio, E; Neri, F; Barreca, F; Mafra, L; Pillinger, M; Pinna, N; Valente, AA
nossos autores
Anabela Tavares Aguiar Valente
Investigador Principal
Luís Mafra
Investigador Principal
Maria Margarida Feitor Pintão Moreno Antunes
Investigador Júnior
Martyn Pillinger
Investigador Principal
Patrícia Alexandra Ferreira Russo
Bolseiro de pós-Doutoramento
Patrícia dos Santos Neves
Investigador Auxiliar
Paul Vincent Wiper
Bolseiro de pós-Doutoramentoagradecimentos
This work was partly financed by FEDER (Fundo Europeu de Desenvolvimento Regional) through COMPETE (Programa Operacional Factores de Competitividade) and by national funds through the FCT (Fundacao para a Ciencia e a Tecnologia) within the project CICECO - FCOMP-01-0124-FEDER-037271 (FCT ref. PEst-C/CTM/LA0011/2013). The FCT and the European Union are acknowledged for grants to P.A.R. (SFRH/BPD/79910/2011), M.M.A. (SFRH/BPD/89068/2012) and P.N. (SFRH/BPD/73540/2010) co-funded by MCTES and the ESF through the program POPH of QREN. We acknowledge the Portuguese National NMR Network (RNRMN), supported with funds from the FCT. BP Amoco Chemical Company is acknowledged for sponsoring P.V.W.'s postdoc grant. L.M. thanks the FCT for the FCT Investigator consolidation grant IF/01401/2013.