Journal of Analytical and Applied Pyrolysis 101 (2013) 96–102 Contents lists available at SciVerse ScienceDirect Journal of Analytical and Applied Pyrolysis journa l h o me page: www.elsevier.com/locate/jaap Thermodesorption coupled to GC–MS to characterize volatiles formation kinetic during wood thermodegradation Kévin Candelier a , Stéphane Dumarc ¸ ay a , Anélie Pétrissans a , Mathieu Pétrissans a , Pascal Kamdem b , Philippe Gérardin a,∗ a Laboratoire d’Etudes et de Recherches sur le Matériau Bois, EA 4370, Université de Lorraine, Faculté des Sciences et Technologies, BP 70239, F-54506 Vandoeuvre-lès-Nancy, France b School of Packaging, Michigan State University, 448 Wilson Road, East Lansing 48824, MI, USA a r t i c l e i n f o Article history: Received 7 April 2012 Accepted 6 February 2013 Available online 14 February 2013 Keywords: Activation energy Arrhenius equation Degradation product Hardwood Kinetic Mild pyrolysis Softwood a b s t r a c t Identification of volatile degradation products generated and released during wood mild pyrolysis is important to better understand thermodegradation mechanisms. Previous studies have shown that ther- modesorption coupled to GC–MS is an attractive tool to characterize and quantify products formed during wood thermal treatment indicating higher susceptibility of hardwoods to thermodegradation compare to softwoods. The aim of this study is to elucidate wood thermodegradation pathways with special empha- sis on the kinetics reactions. To achieve this objective, one hardwood species (beech) and one softwood species (Silver fir) were subjected to thermal treatment directly in the thermal desorption glass tube of thermodesorber connected to GC–MS using helium as carrier and at temperatures of 210 and 230 ◦ C for different times ranging from 10 to 80 min. The volatiles compounds formed were analyzed by gas chromatography coupled to mass spectroscopy. From GC–MS data collected in this study, the kinetic curves of the formation of some of the products as a function of thermal treatment duration were estab- lished. Assuming that acetic acid and furfural were formed from hemicelluloses and vanillin from lignin, Arrhenius equation was used to estimate the mean activation energy formation of these two degradation by-products allowing obtaining indirect information on the thermal stability of both polymer. © 2013 Elsevier B.V. All rights reserved. 1. Introduction Wood heat treatment by mild pyrolysis is used to improve wood properties such as its decay durability and dimensional sta- bility [1,2]. These new properties are the result of chemical and physical modifications of wood cell wall polymers during thermal treatments [3–5]. Therefore, the knowledge of the mechanisms schemes of the wood thermo-degradation is of great interest to unravel important parameters that will fit in a kinetic model, usable and applicable to the industrial/commercial wood heat treatment process, and help in drafting recommendations concerning the operating temperature, residence time to improve and control the properties of thermally treated wood. Previous studies have shown that thermodesorption coupled to GC–MS is a robust and reliable method for identification and quan- tification of volatile degradation products formed during wood mild pyrolysis [6]. This method can therefore be used to yield valu- able information on mechanisms of wood thermodegradation and to understand the differences in kinetics between thermally treated softwood and hardwood species [7,8]. The higher susceptibility of ∗ Corresponding author. Tel.: +33 3 83 68 48 40. E-mail address: philippe.gerardin@lermab.uhp-nancy.fr (P. Gérardin). hardwoods to thermodegradation compared to softwoods has been attributed to their higher content in acetyl groups from acetylated glucoroxylan leading to the formation of considerable amount of acetic acid involved in hemicelluloses and lignin degradation. Even if softwoods and hardwoods present different chemical compo- sitions, similar degradation products have been identified during mild pyrolysis excepted for degradation products resulting from syringyl units. The main difference in the thermo-degradation kinetics was related to the thermal treatment temperature levels and the amount of acetic acid released during thermal treatment. Thermal degradation of softwoods occurred in the temperature range of 210–230 ◦ C. Slightly lower temperatures are necessary for hardwood species. The majority of kinetic methods used in the area of thermal analysis to determine the rate of degradation of wood consider two variables, the temperature and the extent of conversion. The extent of conversion is determined as a fraction of the total mass loss in the thermodegradation process involv- ing numerous reactions. Thermal analysis methods are therefore not species specific and cannot be directly linked to specific reac- tions of molecules. Consequently, experimental parameters are generally “global parameters” corresponding to the contribution of numerous intrinsic kinetic parameters of the different individual reactions. Contrary to these methods, the use of thermodesorption coupled to GC–MS allowed the identification and quantification of 0165-2370/$ – see front matter © 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.jaap.2013.02.006