Please cite this article in press as: A.d.C. Fraga, et al., J. Mol. Catal. A: Chem. (2015), http://dx.doi.org/10.1016/j.molcata.2015.12.005 ARTICLE IN PRESS G Model MOLCAA-9707; No. of Pages 10 Journal of Molecular Catalysis A: Chemical xxx (2015) xxx–xxx Contents lists available at ScienceDirect Journal of Molecular Catalysis A: Chemical journal homepage: www.elsevier.com/locate/molcata Biomass derived solid acids as effective hydrolysis catalysts Adriano do Couto Fraga a,∗ , Cristina Pontes Bittencourt Quitete a , Vitor Loureiro Ximenes a , Eduardo Falabella Sousa-Aguiar b , Isabel M. Fonseca c , Ana M.Botelho Rego d a PETROBRAS S.A., CENPES R&D Centre, Cidade Universitária, Av. Horácio Macedo, 950, Rio de Janeiro, RJ CEP 21.941-915, Brazil b Department of Organic Chemistry, School of Chemistry, Federal University of Rio de Janeiro, Brazil c LAQV-REQUIMTE, Department of Chemistry, Faculty of Science and Technology, Universidade NOVA de Lisboa, Campus da Caparica, Caparica 2829-516, Portugal d Centro de Química-Física Molecular and Institute of Nanoscience and Nanotechnology, Instituto Superior Técnico, University of Lisbon, Av. Rovisco Pais, Lisboa 1049-001, Portugal a r t i c l e i n f o Article history: Received 30 October 2015 Received in revised form 4 December 2015 Accepted 9 December 2015 Available online xxx Keywords: Oligomers Hydrolysis Biomass Solid acids a b s t r a c t The conversion of cellulose into products with higher added value often includes a depolymerization step to obtain glucose, its fundamental unity. The depolymerization reaction is carried out via hydrolysis of the -1,4-glycosidic bond. The search for a solid acid catalyst capable of breaking these bonds is gaining increasing prominence in the literature. In this regard, sulfonated carbons have shown promising results. This work evaluated the use of a residue from the extraction of palm oil as raw material for the pro- duction of sulfonated carbons. The raw material was carbonized and sulfonated. The obtained solid acids were tested in the hydrolysis of cellobiose, a dimer of glucose often used as a model compound for cel- lulose. The hydrolysis reaction is the first step in converting renewable carbon sources into chemical products and biofuels. Some aspects were investigated, as the effect of carbonization temperature on the concentration of sul- fonic groups, the results showing that the content thereof reached a maximum value at 300 ◦ C. Regarding the hydrolysis of cellobiose, it has been identified that there is a relationship between the concentration of sulfonic acid groups and the activity of these catalysts. However, there is a drop in the turnover num- ber as the amount of sulfonic acid sites increases. This was related to a preferred position sulfonation mechanism. Furthermore, sulfonated carbons showed higher activity than the commercial acid resins, indicating that this material may be a good option for the generation of solid acid catalysts. © 2015 Published by Elsevier B.V. 1. Introduction The conversion of cellulose into products with higher added value often includes a depolymerization step to obtain glucose, via the hydrolysis of the -1,4-glycosidic bond. However, to enable hydrolysis of -1,4 glycosidic bonds, strong Bronsted acids are required. Many solids display strong Bronsted acid sites. The achievement of hydrolysis reaction with a solid acid is still a chal- lenge. Traditionally, the reaction is carried out using inorganic acids as catalysts. Nevertheless, some aspects such as corrosion of process units, make the use of solid acids rather attractive. The lit- erature reports interesting results using sulfonated carbons, which ∗ Corresponding author at: Av. Horácio Macedo, 950, Cidade Universitária, Rio de Janeiro, RJ CEP 21.941-915, Brazil. Fax: +55 21-21625036. E-mail address: adrianofraga@petrobras.com.br (A.d.C. Fraga). may be easily recycled and have sulfonic acid groups with acid strength similar to sulfuric acid [1]. Along with applications in esterification and transesterification for biodiesel production [2,3], cellulose and oligosaccharide hydrolysis reactions are the most common applications of sulfonated carbons presented in the lit- erature. Cellulose is a linear polymer molecule formed by glucopyranose rings linked by -1,4 chemical bonds, between carbons 1 and 4 of the ring. This type of connection provides a higher stability to cellulose compared to other polysaccharides such as starch, which is formed by -1,4 chemical bonds. Due to the symmetry of the - 1,4 bond, hydrogen bonds between adjacent hydroxyl groups of the two rings are formed, increasing stability of the -1,4 bond. -1,4 chemical bonds decrease the water solubility of oligosaccharides even with few rings, thereby protecting the -1,4 glycosidic bond from hydrolysis reactions [4]. http://dx.doi.org/10.1016/j.molcata.2015.12.005 1381-1169/© 2015 Published by Elsevier B.V.