resumo
The sustainable conversion of biomass and biomass-derived platform chemicals demands efficient catalytic processes for which modified versions of zeolites can be strategically important. The catalytic potential of bulk and composite catalysts which simultaneously feature zeolite crystallinity, mesoporosity and Zr and Al sites were explored for the valorisation of furfural (Fur; industrially produced from hemicelluloses) via integrated reduction and acid reactions in alcohol media, to give useful bio-products (bioP), namely, furanic ethers, levulinate esters and angelica lactones. Different synthetic strategies were used starting from zeolite microcrystals or nanocrystals. A composite consisting of nanocrystals of Zr,Al-Beta embedded in a mesoporous matrix is reported for the first time. In a different synthesis approach, a bulk mesoporous zeotype material was prepared by post-synthesis alkaline/acid/impregnation treatments, and explored for the first time as a catalyst for a one-pot reduction/acid reaction system. Characterisation studies of the morphology, structure, texture and nature of the Al and Zr sites (Al-27 MAS NMR spectroscopy, FT- IR spectroscopy of adsorbed pyridine or deuterated acetonitrile) helped understand the influence of material properties on catalytic performance. These types of materials are active and stable catalysts for the integrated conversion of Fur to bioP.
palavras-chave
LEWIS-ACID SITES; PONNDORF-VERLEY REDUCTION; SILICA ZEOLITE-BETA; MQ MAS NMR; GAMMA-VALEROLACTONE; ETHYL LEVULINATE; MICRO/MESOPOROUS COMPOSITES; SI/AL RATIO; TRANSFER HYDROGENATION; MOLECULAR-SIEVES
categoria
Chemistry
autores
Antunes, MM; Neves, P; Fernandes, A; Lima, S; Silva, AF; Ribeiro, MF; Silva, CM; Pillinger, M; Valente, AA
nossos autores
Anabela Tavares Aguiar Valente
Investigador Principal
Carlos Manuel Silva
Professor associado
Maria Margarida Feitor Pintão Moreno Antunes
Investigador Júnior
Martyn Pillinger
Investigador Principal
Patrícia dos Santos Neves
Investigador Auxiliaragradecimentos
This work was developed within the scope of the project CICECO-Aveiro Institute of Materials, POCI-01-0145-FEDER-007679 (FCT Ref. UID/CTM/50011/2013), financed by national funds through the FCT/MEC and appropriately co-financed by FEDER under the PT2020 Partnership Agreement. The FCT and the European Union are acknowledged for grants to M. M. A. (SFRH/BPD/89068/2012), P. N. (SFRH/BPD/73540/2010), A. F. S. (SFRH/BD/101018/2014) and A. F. (SFRH/BPD/91397/2012), cofunded by MCTES and the ESF through the program POPH of QREN. The authors thank Vania Freitas for support with DR UV-vis spectroscopy measurements.