resumo
Microporous silicoaluminophosphates SAPO-5, SAPO-11 and SAPO-40 have been tested as solid acid catalysts in the dehydration of xylose into furfural (FUR) under biphasic aqueous-organic conditions, at 170 degrees C. For all materials, no decrease in catalytic activity is observed after three consecutive recycling runs. Furfural yields at 4 h using SAPO-11 (34-38%) are comparable with that for HMOR zeolite with Si/Al similar to 6 (34%), under similar reaction conditions, while H(2)SO(4) (0.03 M) gives 2% FUR. Complete xylose conversion is reached within 16-24 h, with furfural yields of up to 65%. Bronsted and Lewis acidity of the silicoaluminophosphates was determined through FTIR analysis of adsorbed pyridine, and tentatively correlated with the catalytic performances.
palavras-chave
LIQUID-PHASE DEHYDRATION; SOLID ACID CATALYSTS; 12-TUNGSTOPHOSPHORIC ACID; MOLECULAR-SIEVES; ZEOLITE; FRUCTOSE; GLUCOSE; SAPO-5
categoria
Chemistry
autores
Lima, S; Fernandes, A; Antunes, MM; Pillinger, M; Ribeiro, F; Valente, AA
nossos autores
Anabela Tavares Aguiar Valente
Investigador Principal
Maria Margarida Feitor Pintão Moreno Antunes
Investigador Júnior
Martyn Pillinger
Investigador Principalagradecimentos
This work was partly funded by the FCT, POCTI and FEDER (project POCTI/QUI/56112/2004 and PTDC/QUI/71198/2006). The authors thank Prof. C.P. Neto for helpful discussions, Dr. Z. Lin (CICECO) for supplying a mordenite sample, and Dr. F. Domingues for access to HPLC equipment. S.L. and M.M.A. are grateful to the FCT for grants.