Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 31023
Optimization of Quercus cerris Bark Liquefaction

Authors: Luísa P. Cruz-Lopes, Hugo Costa e Silva, Idalina Domingos, José Ferreira, Luís Teixeira de Lemos, Bruno Esteves


The liquefaction process of cork based tree barks has led to an increase of interest due to its potential innovation in the lumber and wood industries. In this particular study the bark of Quercus cerris (Turkish oak) is used due to its appreciable amount of cork tissue, although of inferior quality when compared to the cork provided by other Quercus trees. This study aims to optimize alkaline catalysis liquefaction conditions, regarding several parameters. To better comprehend the possible chemical characteristics of the bark of Quercus cerris, a complete chemical analysis was performed. The liquefaction process was performed in a double-jacket reactor heated with oil, using glycerol and a mixture of glycerol/ethylene glycol as solvents, potassium hydroxide as a catalyst, and varying the temperature, liquefaction time and granulometry. Due to low liquefaction efficiency resulting from the first experimental procedures a study was made regarding different washing techniques after the filtration process using methanol and methanol/water. The chemical analysis stated that the bark of Quercus cerris is mostly composed by suberin (ca. 30%) and lignin (ca. 24%) as well as insolvent hemicelluloses in hot water (ca. 23%). On the liquefaction stage, the results that led to higher yields were: using a mixture of methanol/ethylene glycol as reagents and a time and temperature of 120 minutes and 200 ºC, respectively. It is concluded that using a granulometry of <80 mesh leads to better results, even if this parameter barely influences the liquefaction efficiency. Regarding the filtration stage, washing the residue with methanol and then distilled water leads to a considerable increase on final liquefaction percentages, which proves that this procedure is effective at liquefying suberin content and lignocellulose fraction.

Keywords: Optimization, Liquefaction, alkaline catalysis, Quercus cerris bark

Digital Object Identifier (DOI):

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 942


[1] Kasaplıgil, B., “Past and present oaks of Turkey”, Phytologia, vol. 49,1981, pp. 95-146.
[2] Abi-Saleh, B. e Safi, S., “Carte de la Végétation du Liban”; Ecologia Mediterranea XIV (1/2), 1988, pp. 123-142.
[3] Yaltırıc, F., “Türkyie meşeleri teşis kılavuzu.”, Tarım Orman ve Köyişleri Bakanlığı Genel Müdürlüğü Yayınları. Yenilik Basimevi. Istambul. 1984.
[4] Cotti, C., “Molecular markers for the assessment of genetic variability in the threatened plant species.”, Tese de Doutoramento, Università degli studi di Bologna, 2008.
[5] Berkel, A. e Bozkurt, Y., “Untersuchungen über die makroskopischen und anatomischen holzmerkmale der wichtigsten Türkischen Eichenarten”, Istanbul Universitesi Orman Fakultesi Yayinlari, Kutulmus Matbaasi, Istanbul, 1961, 78.
[6] La Marca, O., Uzielli, L. e Zanuttini, R., “Possibilità di impegio del legname di cerro (Quercus cerris L.) in Italia. Indagini preliminari su alcuni popolamenti e prove sperimentali per l'industria dei compensati”, L'Italia Florestale e Montana 1, 1983, pp. 33-62.
[7] Bartha, S., “Cercatari Privind FActorii De Variatie A Caliatatii Lemnului De Cer Din Padurea Bobostea (Jud. Bihor)”, Rezumatul tezei de doctorat, Universitatea Transilvania Din Brasov, 2011.
[8] Todaro, L., Zanuttini, R., Scopa, A., Moretti, N., “Influence of combined hydro-thermal treatments on selected proprerties of Turkey oak (Quercus Cerris L.) wood”, Wood Science and Technology, vol. 46, 2012, pp. 563-578.
[9] Mun, S., Gilmor, I. e Jordan, P., “Effect of Organic Sulfonic Acids as Catalysts during Phenol Liquefaction of Pinus radiata Bark”, J. Ind. Eng. Chem., vol. 12, 2006, pp. 720-726.
[10] Amorim. Diversidade e Aplicações. Amorim. (Online) 2015.
[11] Alma, H.M. e Bastiirk, M.A., “Co-condensation of NaOH-catalysedliquefied wood wastes, phenol, and formaldehyde for the production of resol-type adhesives”, Ind. Eng. Chem. Res., 2001, pp. 5036–5039.
[12] Gandini, A., Neto, C.P. e Silvestre, A., “Suberin: a promosing renewablere source for novel macromolecular materials”, Prog. Polym. Sci., vol. 31, 2006, pp. 878–892.
[13] Jin, Y.; Ruan, X.; Cheng, X.; Lü, Q., “Liquefaction of lignin by polyethyleneglycol and glycerol.”, Bioresource Technology, 2011, pp. 3581–3583.
[14] Lin, L.; Yoshioka, M.; Yao; Y.; Shiraishi, N., “Liquefaction of wood in the presence of phenolusing phosphoric acid as catalyst and the flow properties of the liquefied wood”, Journal of Applied Polymer Science, vol. 52, 1994, pp. 1629–1636.
[15] Mun, S., Hassan, E., “Liquefaction of lignocellulosic biomass with mixtures of ethanol and small amounts of phenol in the presence of methanesulfonic acid catalyst”, J. Ind. Eng. Chem., vol. 10, 2004, pp. 722–727.
[16] Nasar, M.; Emam, A.; Sultan, M.; Hakim, A., “Optimization and characterization of sugar-cane bagasse liquefaction process”, Indian J. Sci. Technol., 2010, pp. 207–212.
[17] Min, N., Zhao, G, Alma, H.M., “Polycondensation reaction and its mechanism during lignocellulosic liquefaction by an acid catalyst: a review”, Forestry Studies in China, vol. 13, 2011, pp. 71-79.
[18] Pereira, H., “Chemical composition and variability of cork from Quercus suber L.”, Wood Sci. Technol., vol. 22(3), 1988, 211-218.
[19] Neto, C.P., Seca, A., Fradinho, D., Coimbra, M.A., Domingues, F., Evtuguin, D., Silvestre, A., Cavaleiro, J.A.S., Chemical composition and structural features of the macromolecular components of Hibiscus cannabinus grown in Portugal. Industrial Crops and Products, vol.5(3): 1996, pp. 189-196.
[20] Browning, B.L., “Methods in Wood Chemistry”, Vol. II. John Wiley& Sons, New York, USA, 1967, pp. 406-727.
[21] Martins, J., Cruz Lopes, L., Esteves B., “Otimização da liquefação da madeira de Pinus pinaster com poliálcoois”, Silva Lusitana. Nº Especial. Instituto Nacional de Investigação Agrária e Veterinária, vol. 21, 2013, pp. 177-185.
[22] Şen, A., Miranda, I., Santos, S., Graça, J., Pereira, H., “The chemical composition of cork and plhoem in the rhytidome of Quercus Cerris”, . Industrial Crops and Products, Vol.1 (2), 2010, pp. 417–422.