In the present work, the effect of phenol on the supercritical extraction of the organic matter from Tarfaya's oil shale with toluene was evaluated. The experimental results showed clearly that phenol had a significant effect on the yield and the composition of the oils obtained. Moreover, it was shown that phenol was a very efficient modifier for oil shale, giving a good yield of recovery and a suitable maturation of the organic matter. The pitches prepared by mixing phenol and toluene contain more aromatics and have a high char yield at 950 °C compared to those obtained by extraction with supercritical toluene alone.

Infrared transmission spectra of several molecular gases inside three porous silica samples with pore sizes ranging from 7 nm to several tens of nm have been recorded with a Fourier transform spectrometer. Their analysis shows that consistent values of the percentage of open porosity and average pore size can be retrieved from these non intrusive nor destructive optical measurements. The samples have also been characterized using mercury intrusion/extrusion and the nitrogen sorption method. The results of these different probing techniques are in good agreement when the methods used are adapted to the involved pore size. This consistency demonstrates that light absorption by confined gases is a valuable porosimetry tool.

Binderless activated carbon monoliths have been prepared from date stone of the south of Tunisia (Kébeli). The activation process involved two steps. First, pyrolysis of the samples was conducted up to a temperature of 1000°C under nitrogen flow. The obtained carbon monoliths were then physically activated at 500 900°C under CO2 flow. All samples have been characterized by N2 adsorption, scanning electron microscopy and mercury porosimetry. The activated carbons exhibited a predominant microporosity with specific surface area from 476 m g to 877 m g, and microporous volumes from 0.19 cm g to 0.33 cm g. Key-words: Date stones; Binderless Carbon Monoliths; Physical Activation Résumé: Des monolithes de charbon actif ont été préparés sans liants à partir de noyaux de datte du sud de la Tunisie (Kébili). Le processus d'activation comporte deux étapes. Tout d'abord, une pyrolyse des échantillons est réalisée sous courant d'azote jusqu’à une température de 1000°C. Les monolithes de carbone obtenus ont ensuite été activés physiquement à 500°C ou 900°C sous un courant de CO2. Tous les échantillons préparés ont été caractérisés par adsorption d’azote, par microscopie électronique à balayage et par porosimétrie par intrusion de mercure. Les monolithes carbonés obtenus présentent une microporosité prédominante avec une surface spécifique entre 476 m g et 877 m g, et des volumes microporeux situés entre 0,19 cm g à 0,33 cm g. Mots-Clés : Noyaux de datte, monolithes carbonés sans liant, activation physique Chemical activation with KOH or NaOH is the most common methods to produce activated carbons [2], usually as fine powder [3], thus making its shaping to monoliths an important area of research. The manufacture of monoliths normally involves the use of a binder, which implies a reduction of porosity due to partial blocking, the extent of which depends on the kind and proportion of binder used [4]. The aim of this work is the preparation of activated carbon monoliths of high surface area from date stone by physical activation without using a binder. CO2 was selected as the activation gas as it is clean and easy to handle. Furthermore, it facilitates Souad Rezma and al., Journal Tun. Chem. Soc., 2016, 18, 160-165 161 control of the activation process due to the slow reaction rate at temperature around 800°C [5]. MATERIALS AND METHODS 1. Materials Date stone were acquired from Kebelli (Tunisia). The pits were scratched with a knife to deprive any present fiber from the surface and then dried at 120°C for about 24 h. A solid powder was obtained after grinding and sieving in the desired size grade, then washed with distilled water and dried in an oven at 50°C for 48 h. 2. Activated carbon monolith preparation Date stone powder was first dried at 110°C for 2 h then shaped into cylindrical monoliths (10 mm × 13 mm) by uniaxial pressing at room temperature under 500 MPa. Carbonization of monoliths was carried out in an horizontal tube furnace under N2 flow (100 mL min). The thermal program was as follows: heating from room temperature to 1000°C at a 1°C min rate, including a first plateau at 300°C for 4 h, then a second one at 700°C for 2 h and a final maintenance at 1000°C for 2 h. The obtained carbon monoliths were then activated at 500 or 900°C for 30 min using a CO2 flow of 100 mL min -1 (heating rate 5°C min). The nomenclature of raw date stone monoliths (DSM), carbonized monoliths (CM1000) and activated carbon monoliths (ACM) samples includes also the temperature; for example the carbon monolith activated at 500°C will be labeled ACM500. 3. Characterizations 3.1. Porosity determination The porosity of a porous material is given by the relation: Φ = 1– ρa/ρs where ρa is the apparent (bulk) density and ρs the skeletal density. The experimental porosity Φexp and pore size distribution of each sample were determined by mercury intrusion porosimetry in a Micromeritics Autopore IV 9500 porosimeter with the following parameters: contact angle = 130 °, mercury surface tension = 485 mN m, maximum intrusion pressure = 124 MPa. 3.2. Skeletal density The skeletal density ρs of the materials was determined using a Micromeritics Accupyc II 1340 helium pycnometer. 3.3. Specific surface area determination The specific surface area was determined by nitrogen sorption measurements on a Micromeritics ASAP 2010 analyzer. The collected data were subjected to the Brunauer, Emmett and Teller (BET) treatment [6]. The mesopore and micropore volumes were obtained by application of the αS method [7]. The total pore volume Vt was obtained from the amount adsorbed at a relative pressure p/p0 of 0.99, while the mesopore volume Vmeso was obtained from the difference between the total pore volume and the microporous volume. 3.4. Scanning electron microscopy investigation The morphology of the monoliths was observed by scanning electron microscopy (SEM) in a Hitachi TM-1000 microscope. Photographs were taken at several different magnifications between ×500 and ×10,000. Pieces of sample (section of about 0.5 cm) cut from the corresponding monoliths were mounted on a carbon tab, which ensured a good conductivity. A thin layer of goldpalladium was sputtered on the sample fragment prior to analysis. 3.5. Thermogravimetric analysis (TGA) Materials weight loss studies were performed on a Netzsch STA 409 thermobalance under high purity argon atmosphere. TGA and DTG data were obtained under argon flow (60 mL min) at a heating rate of 5°C min and the temperature ranged from 30 to 1000°C 3.6 Elemental analysis The C, H, N and O elemental analyses were carried out in a Thermo Fisher Flash 2000 analyzer ensuring a precision of ± 0.3%. RESULTS AND DISCUSSION 1. Thermogravimetric analysis of date stone powder The thermogravimetric curve of date stone powder under inert atmosphere is shown in Figure 1. Fig. 1. Thermogravimetric analysis of date stone powder. 162 Souad Rezma and al., Journal Tun. Chem. Soc., 2016, 18, 160-165 Three stages of evolution can be observed during pyrolysis of the sample: dehydration, decomposition of polymers and carbonization. Carbonization program of the samples was then established according to these results. The TG curve shows a first weight loss (2.5%) up to 155°C due to moisture elimination. The second weight loss (73%) arising between 155°C and 550° C, corresponds to the carbonization step. This major weight loss is due to the elimination of volatile matters and tars. Carbonization proceeds in two steps: a first range from 250°C to 350°C and a second one from 250°C to 500°C attributed to cellulose and lignin decomposition, respectively [8]. Above 550°C the weight loss is small indicating that the basic structure of the char has been formed. 2. Visual aspect of the different samples SEM image of date stone monolith (DSM) (Figure 2) shows that this material has a very rough surface, an intact external structure where Fig. 2. SEM micrograph of date stone monolith (DSM) the caking agglomeration of the carbonaceous aggregates was not observed. The shape of the samples is preserved during the carbonization but a shrinking in volume was observed. This behavior can be visualized by comparing: a) Compressed date stone monolith DSM, b) Carbonized monolith CM1000, and, c) Activated monolith ACM900 (Figure 3). Volumetric shrinkage is associated to a weight loss during carbonization. 3. Elemental analysis of samples The result of elemental analysis of the different samples is reported in Table I. Data reported indicates a strong increase in C/H and C/O ratios during the carbonization step as expected. The pyrolysis stage under neutral atmosphere allows to obtain a carbonaceous product by the volatilization of hydrogen, oxygen and nitrogen traces. In this process, hydrogen and oxygen elimination occurs in the form of CO, CO2 and H2O. The release of monoxide and carbon Fig.3. Visual aspect of date stone monoliths: a) compressed date stone monolith DSM, b) Carbonized monolith CM1000, c) Activated monolith ACM900. Elemental analysis (%) Atomic ratio Sample C H N O C/H C/O DSM 46.83 6.66 0.74 40.55 0.59 1.54 CM1000 78.17 0.99 0.58 8.48 6.58 12.29 ACM500 78.07 0.93 0.39 11.16 6.99 9.33 ACM900 73.41 1.45 0.53 12.41 4.22 7.89 Table I: Elemental analysis of the different samples. Souad Rezma and al., Journal Tun. Chem. Soc., 2016, 18, 160-165 163 dioxide is generally observed between 200 and 300°C. The cellulose is degraded between 240°C and 360°C. At 300 and 400°C, the production of hydrocarbons occurs, between 400 and 500°C, there is a release of a large quantity of gas hydrocarbons and thick tar. From 500 to 700°C, the production of gas refers mainly to hydrogen, carbon monoxide and hydrocarbons. From 700 with 1000°C, the major remaining product is carbon residue [9]. Activation under CO2 at 500°C or 900°C do not modify significantly these data, but allows the formation of micropores during activation when the temperature exceeds 700°C. 4. Morphology analysis of the pyrolysed and activated carbons SEM images of pyrolysed (CM1000) and activated (ACM500, ACM900) carbon monoliths are presented in Figure 4. As can be seen from these clichés, pyrolysis creates some porosity (Fig. 4a). After activation, the porosity is more developed. By comparing Fig. 4b and Fig. 4c, we can notice that the porosity is more developed with an activation temperature of 900°C than with 500°C, which indicates clearly that a regular macroporosity and a rather homogeneous surface are obtained by activation at 900°C under CO2 for 30 min (Fig. 4c) [10]. 5. Porous morphology of pyrolyzed and activated carbons The experimental porosity Φexp of the different samples was estimated by mercury intrusion porosimetry. The obtained values are: Φexp = <0.01, 0.23, 0.40 and 0.52 for DSM, CM1000, AC500, and AC900 respectively. Raw date stone powder monolith (DSM) is, as expected, almost Fig. 4. SEM micrograph of CM1000 (a), ACM500 (b), ACM900 (c) Fig. 5. N2 Adsorption-desorption isotherms of pyroly

In this work, a composite prepared with a phenolic matrix and reinforced with carbon fibers was subjected to degradation by phenol under subcritical conditions.Phenol was able to solubilize the resin matrix under relatively mild conditions (T ≤ 390 °C, P < 0.5 MPa) without altering the carbon fibers, as confirmed by scanning electron microscopy and by mechanical characterization of the fibers recovered after heat treatment.

Oil shale has constituted for a long time an economical hope for countries that possess important reserves of these rocks and that view to use them as an energy source substitute for petroleum.Morocco, with estimated reserves of 93 billion tons, is increasingly looking at oil shale as an alternative energy source. A lot of studies have concentrated on oil shale located in Timahdit and Tarfaya, because of their high percentage of organic matter. Most of the studies focus either on the effect of various parameters on the yield and the quality of the oil obtained by conventional pyrolysis, or on the characterization of these oils by different physical and chemical techniques.This paper explores the possibility to produce new materials, starting from the Moroccan oil shale, for different applications. More specifically, we aimed to demonstrate that the organic fraction of the oil shale could be used as precursors of low cost carbon fibres or graphitizable carbon, after appropriate chemical treatments resulting in a "maturation" of this organic phase. We also showed that this organic fraction of the Moroccan oil shale has interesting bioactive properties and that it could be used as a source of compounds with pharmaceutical interests.

Supercritical extraction of Tarfaya's oil shale by toluene revealed that the solvent proportion has a significant effect on the yield and the composition of the obtained oils. The analyses carried out on the recovered oils allowed to establish the optimal operating conditions giving the highest oil yields. In addition, it was observed that these oils contain a large proportion of aromatics compounds.

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. (C) 2008 Elsevier B.V. All rights reserved.

Stable water-in-oil high internal phase emulsions, containing styrene and divinylbenzene monomers and exfoliated montmorillonite, were prepared and polymerized to obtain nanocomposite microcellular materials. The porous structure was investigated by scanning electron microscopy, mercury intrusion porosimetry, and nitrogen adsorption/desorption analyses. The exfoliation of clay was investigated by X-ray diffraction and transmission electron microscopy analyses. The presence of inorganic filler did not modify the microcellular structure of the composite, while the use of modified clay significantly enhanced its mechanical properties. No influence on the thermal degradation was noted, except for materials with high clay content that tended to deteriorate at lower temperature than the other materials. (c) 2007 Wiley Periodicals, Inc.

Ex-rayon carbon yarns have been prepared according to an original route characterized by a fast pyrolysis step in the presence of an organosilicon compound. The evolution of the mechanical and physicochemical properties of the fibres throughout the transformation of cellulose into carbon showed that the organosilicon additive was necessary to obtain carbon yarns exhibiting satisfactory mechanical behaviour and to improve significantly the fracture properties of the ex-rayon carbon fibres.

Self-assembled monolayers grafted onto silicon surfaces were obtained from the hydrosilylation products by trialcoxysilanes of naturally occurring phenolic lipid allyl ethers. The as-obtained materials were characterized by various physical and physicochemical methods. Thus, contact angles of water drops showed that they possess very high hydrophobicity. Their excellent regularity was corroborated by AFM microscopy. The frequencies of the stretching CH2 infrared modes indicate the presence of alkyl chains mainly in the trans/trans conformation. Additionally, optical ellipsometry and quartz microbalance measurements enabled us to estimate the thickness of the films. The results, as a whole, are in good agreement with the formation of densely packed monolayers.

Phenol was used for the recovery of the organic matter from Tarfaya!s oil shales in subcritical conditions. The analyses carried out on the recovered oils revealed that phenol had a significant role on the increase of the yield of recuperation, amount of maltenes, aromatic compounds and the reduction of the amount of sulphur in oils.

Stabilization of naphthalene-derived synthetic mesophase pitch was achieved by controlled oxidation or reaction with phenanthrenequinone (PHQ) in order to suppress the swelling during high-temperature treatments. The modified pitches were characterized and their carbonization behaviour was studied by thermogravimetry–mass spectrometry. The results show that naphthenic groups are involved in the stabilization process. PHQ reacts via cycloaddition reactions, yielding oxygen-containing non-planar structures, a feature that accounts for the loss of anisotropic properties of the final material.

Macromolecular monoliths were synthesised from concentrated emulsions. Matrixes with only a polyurethane network were too soft and it was necessary to add to the formulation a rigid network such as polystyrene to obtain a material with a good dimensional stability. Either unconnected or interconnected interpenetrating networks were prepared, the later by using hydroxybutyl methacrylate as a comonomer that chemically links both networks. The modifications of the mechanical properties were evaluated by estimating the Young's modulus from compression tests.

Tarfaya oil shale was subjected to supercritical toluene extraction. The experimental results obtained show clearly that the mineral matter and phenol have a significant effect on the yield and the composition of the obtained oil.

New pitches were obtained from the extraction of Moroccan oil shales. Their pyrolysis was studied in the temperature range of 1100–2800 °C by Raman spectroscopy and X-ray diffraction. The graphitization degree of the resulting carbon was tightly dependent on the composition of the pitch. Moreover, it was shown that phenol was a suitable extraction solvent to produce graphitizable carbon at relatively low temperature (T≥1800°C).

A series of organosilylboranes has been investigated by IR spectroscopy and semiempirical calculations (MNDO/d force field methods). Computational studies afforded Si–B stretching wavenumbers in good agreement with the experimental IR bands observed in the range of 480–650cm−1. It was shown that these characteristic Si–B bond vibrations depend on the structure of molecules and on the size of substituting groups. Thus, compounds possessing small and medium substituting groups (H, Me) and those having a symmetry element give pure Si–B stretching bands. In the case of silylboranes bearing bulky groups, assignments of bands involving Si–B vibrators were achieved via comparison of experimental and theoretical IR spectra with those of reference molecules containing the parent organosilyl- or organoboryl moieties. An experimental absorption band near 600cm−1 could reasonably be assigned to ν(Si–B).

This work describes the elaboration method of a new adsorbent material from Moroccan oil shale. The manufacturing of this material was carried out by thermal treatement of carbonate-free oil shale originating from the Tarfaya deposit. The effect of temperature and activation time on the, adsorption parameters of the material was studied using methylene blue and bichromate ions as pollutants. The results show that the optimum conditions which provide the best adsorbent properties are T = 250degreesC and t = 1 hour.

Novel stable organosilylboranes possessing dimesityl groups attached to boron were synthesised. They gave an addition reaction with terminal acetylenic hydrocarbons in the presence of a transition metal complex. Thus, (diphenylmethylsilyl)dimesitylborane and (diphenyl-tert-butylsilyl)dimesitylborane reacted in good yields with phenylacetylene and alk-1-ynes in the presence of Pd2(dba)3(etpo)2 as a catalyst. The structures of the products were determined by NMR spectroscopy using INEPT techniques coupled to computational simulation. Various heteronuclear coupling constants J13C−H and J29Si−H were determined for the first time in this series. The results showed that the dimesitylboryl group added to the terminal acetylenic carbon atom and the organosilyl group to the internal carbon atom, according to a regio- and stereoselective syn-addition.

Rayon fibres were pyrolysed under inert gas flows up to 1200 degreesC. Changes in the mechanical properties of the fibres at various stages of the thermal treatment were studied and correlated with structural analyses of the char by CP/MAS C-13 NMR and DRIFT spectroscopies. The force/displacement curve of fibres pyrolysed at 500 degreesC is non-linear but reversible within the deformation, which is approximately 10% at ultimate failure. (C) 2001 Elsevier Science Ltd. All rights reserved.