Investigation of biodiesel production by HUSY and Ce/HUSY zeolites: Influence of structural and acidity parameters

Authors:  Luciana D. Borges, Nayara N. Moura, Andréia A. Costa, Patrícia R.S. Braga, José A. Dias, Sílvia C.L. Dias, Julio L. de Macedo, Grace F. Ghesti

Abstract:
In this work, activities of HUSY and Ce/HUSY zeolites were studied in transesterification cycles of soybean oil and ethanol to produce biodiesel. The characterization of the materials was performed by FT-IR, XRD, BET method and pyridine adsorption followed by thermal analyses. TG/DTG results indicated a decrease of acid sites for both samples after each reaction cycle. However, Ce/HUSY zeolite showed a superior stabilization of acidic sites after three catalytic cycles and intermediary activation procedures. Biodiesel production exhibited high conversion levels (>96%) for both zeolites in all transesterification cycles. Surface area and pore volume measurements evidenced that cerium incorporation reduced the number of acid sites by interacting with OH groups in the micropore and external area of the zeolitic surface. This interaction resulted in an acid and structural stability, which provided a better activity (99%) than HUSY (96%). The higher conversion values obtained by zeolites showed a final product with a different distribution when compared with the traditional transesterification process. The identification of free fatty acids, diethyl and glycerol ethers in the final products and the reduction of unsaturated compounds indicated that parallel reactions also occurred in the studied systems. Nonetheless, the biofuel produced showed high ester content and did not present changes in its calorific power. 

Keywords:
Biodiesel
Transesterification
USY zeolite
Cerium
Catalytic cycles

Published in: Applied catalysis A: General  (Volume 450, Pages 1-274, 15 January 2013)

Publisher: Elsevier

ISSN Information: 0926-860X

Investigation of biodiesel production by HUSY and Ce/HUSY zeolites: Influence of structural and acidity parameters

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