J. of Supercritical Fluids 47 (2008) 195–199 Contents lists available at ScienceDirect The Journal of Supercritical Fluids journal homepage: www.elsevier.com/locate/supflu New pitches with very significant maturation degree obtained by supercritical extraction of Moroccan oil shales A. Abourriche a,∗ , A. Adil b , M. Oumam b , H. Hannache b , R. Pailler c , R. Naslain c , M. Birot d , J.-P. Pillot d a École Nationale des Sciences Appliquées, B.P. 63, 46000 Safi, Morocco b Laboratoire des Matériaux Thermostructuraux, Faculté des Sciences Ben M’sik, B.P. 7955 Casablanca, Morocco c Université Bordeaux 1/CNRS/CEA/SAFRAN, Laboratoire des Composites Thermostructuraux (LCTS), 3 allée de la Boétie, F-33600 Pessac, France d Université de Bordeaux, Institut des Sciences Moléculaires, CNRS-UMR 5255, 351 cours de la Libération, F-33405 Talence, France article info Article history: Received 16 February 2008 Received in revised form 1 July 2008 Accepted 18 July 2008 Keywords: Oil shale Pitch Supercritical extraction Maturation abstract In the present work, new pitches were obtained by supercritical extraction of Moroccan oil shales with water–shale oil as solvent. The aim of the research was to obtain pitches with very significant maturation degree of the organic matter. The evolution of the pitch structure was studied through indexes calculated from quantitative infrared spectroscopy. The classification of the pitches enabled us to assess their degree of maturation. This allowed us to establish the water–shale oil mixture composition likely to give the best maturation of the oil shale ′ s organic matter. © 2008 Elsevier B.V. All rights reserved. 1. Introduction Currently, the conventional energy resources (natural gas, oil, ... ) of the world are being largely used, so they will not last indef- initely. Therefore, it is necessary to seek for alternatives. A lot of efforts and studies have been carried out in the direction of the oil shales [1–4] whose world reserves are 500 times more signif- icant than those of oil are [5], although the presence of mineral matter makes difficult their use as a source of energy. However, their organic matter, rich in aromatic compounds, could have other applications [6,7]. The present work is part of a more general pro- gram for the exploitation of the Moroccan oil shale deposit of Tarfaya. More specifically, the aim was to try to show that the organic fraction of the oil shales could be used, after appropri- ate chemical treatments resulting in a “maturation” of this organic phase, as precursors of low cost carbon fibres (e.g. activated car- bon fibres) [8]. During this study, we tried to define, from infrared spectroscopy data, the optimal operating conditions likely to give the higher maturation degree of the organic matter of the oil shale. ∗ Corresponding author. Tel.: +212 64456721; fax: +212 24668012. E-mail address: krimabou@hotmail.com (A. Abourriche). 2. Materials and methods 2.1. Materials The oil shale used in this work was from the Tarfaya deposit located in the South of Morocco. This deposit consists of several layers that are in turn subdivided in sub-layers, each having a dif- ferent amount of organic matter. The samples were obtained from the R 3 sub-layer, characterized by its high content of organic mat- ter [9]. The chemical composition of the R 3 sub-layer is given in Table 1. The carbonate-free oil shale (RH) was obtained by dissolution of carbonates with HCl [10,11]. The powdered R 3 shale (20 g, grain size 0.063–0.08 mm) and 80 mL of concentrated HCl (7 M) were introduced in an Erlenmeyer. The mixture was then subjected to magnetic stirring for 4 h. The formed CO 2 was trapped by bubbling in a solution of barium hydroxide. After filtration, the solid residue (referred to as RH) was washed carefully with distilled water, dried at 100 ◦ C and stocked in a sealed plastic bag. 2.2. Apparatus 2.2.1. Preparation of the pitch Supercritical extraction of the sample RH (10g) with a mixture of water [12–14] and shale oil [15] as solvent was conducted in a 120 mL stainless steel autoclave equipped with a stirrer and heated 0896-8446/$ – see front matter © 2008 Elsevier B.V. All rights reserved. doi:10.1016/j.supflu.2008.07.016