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13X zeolite in powder displays higher storage performances and faster hydration kinetics than 13X in beads. Salt-doped zeolite composite in powder form presents lower pore blockage and higher storage performances than composites in beads.

International audience

Modulation is the key element of the comprehensive 2D gas chromatography separation. Forward fill/flush flow modulation is cost effective, robust and suitable for analysis of a wide range of samples. Even though this modulation system is well known, studies regarding its optimization are sparse. In this work, based on hundreds of experiments involving multiple column sets and modulation conditions, an approach was proposed that permits to facilitate the choice of the forward fill/flush flow modulation parameters. A score function was developed that allows to predict the forward fill/flush flow modulation process efficiency as judged by the modulated peak shape. The score function was based on the physical rules for optimized and quantitative forward fill/flush flow modulation proposed in our previous work, which state that the sum of the fill and flush modulation distances should be close to the modulation channel length and that the ratio of the flush and fill distances should be sufficiently high for efficient channel flushing. The score function was embedded in a freely available tool in the form of a forward fill/flush flow modulation calculator, which allows the user either to quickly check the relevancy of the modulation operating conditions or to obtain a suggestion for optimal modulation parameters.

International audience; Gas oils (GOs) analysis is essential for production process control, in order to meet quality standards, to render these products safer for the environment, and to support research for alternative fuels. GOs quantitative analysis can be commonly achieved by employing two-dimensional comprehensive gas chromatography with flame ionization detection (GC × GC-FID) in combination with identification templates. However, in order to perform quantification for families which coelute in GC × GC analysis (e.g., naphthenes/olefins or polynaphthenes/monoaromatics), prefractionation of gas oil before GC × GC analysis is necessary. Recent introduction of the vacuum ultraviolet (VUV) detector has offered new possibilities in GOs analysis, as this detector can discern between the majority of hydrocarbon families thus possibly rendering the gas oil prefractionation unnecessary. Additionally, it can perform quantification according to Beer–Lambert’s law provided that VUV relative response factors (RRFs) are known. The purpose of this work is to report, for the first time, VUV RRFs for numerous hydrocarbons in GOs (∼160) according to their family and their carbon number, permitting to perform their direct quantification without the necessity of GO prefractionation. VUV RRFs were measured by using a GC × GC-VUV/FID dual detection setup in which FID was employed as a quantitative reference. In order to obtain VUV RRFs representative for any gas oil, a set of 14 GOs with different origins was employed. Both VUV RRFs averaged in the 125–240 nm range and spectral VUV RRFs (reference spectra) were obtained. It was demonstrated that VUV RRFs were similar between employed GOs allowing their universal use. Obtained RRFs were used to perform hydrocarbons quantification for a light cycle oil (LCO) by GC × GC-VUV, with olefins and naphthenes being quantified through spectral decomposition. Good comparability with results obtained by prefractionation was observed demonstrating the great interest of the GC × GC-VUV approach for the detailed and rapid analysis of hydrocarbons in gas oils.

The constantly growing demand for energy and the concern about energy security and the environment motivate the production of fuels and chemicals from different sustainable raw materials. Microalgae are considered for producing third-generation biofuels due to their capacity to grow rapidly and the potential for CO2 fixation. In this context, continuous hydrothermal liquefaction (HTL) of carbohydrate-rich microalga, Chlorella sorokiniana (CS) NIES 2273, and lipid-rich microalga, Chlorella vulgaris (CV) NIES 227, was performed. Then, the bio-oil was hydrotreated (HDT) over sulfided NiW/Al2O3. HTL and HDT oils were characterized by elemental analysis, GPC, 13C and 31P-NMR, SimDis, and GCxGC-MS/FID. In HTL oils, C16 and C18 carboxylic acids were the major components found, reaching 28 wt.% and 34 wt.% of bio-oil from CS and CV, respectively. C16 and C18 fatty amides were also found in both HTL oils, with higher concentrations in the CV bio-oil. These fatty molecules were converted during the hydrotreatment step resulting in a biofuel composed mainly of C15-C18 aliphatics hydrocarbons that felt primarily in the diesel range. The bio-oil from CV showed a lower aromaticity degree, lower O/C and N/C ratio, and higher H/C ratio, whereas the bio-oil from CS was more challenging to upgrade and showed higher amounts of cyclic oxygen and nitrogen compounds, such as phenols and pyrroles. Three times higher amounts of lipids in the CV microalgae led to three times higher biofuel production. Lastly, analysis of the used hydrotreating catalysts showed iron accumulation on both catalysts after upgrading and a similar coke structure.

RMN+ECI2D:ING+FWI:AGH:YMO:CLO:DFA:JEC; International audience; Herein, we report the molecular-level structuration of two full photosystems into conjugated porous organic polymers. The strategy of heterogenization gives rise to photosystems which are still fully active after 4 days of continuous illumination. Those materials catalyse the carbon dioxide photoreduction driven by visible light to produce up to three grams of formate per gram of catalyst. The covalent tethering of the two active sites into a singleframework is shown to play a key role in the visible light activation of the catalyst. The unprecedented long-term efficiency arises from an optimal photoinduced electron transfer from the light harvesting moiety to the catalytic site as anticipated by quantum mechanical calculations and evidenced by in-situ ultrafast time-resolved spectroscopy.

fff; International audience; Hydrocracking converts heavy feeds mainly into middle distillate products. Co-processing these bio-feeds with vacuum gas oil is a possible production route for biofuels. Stabilized bio-liquid from fast pyrolysis and hydrothermal liquefaction bio-crude were mixed with vacuum gas oil (10–20 wt%) and hydrocracked over a bifunctional catalyst. The impact of the bio-liquids on conversion and middle distillate selectivity were investigated. The liquid products were analyzed by several methods such as 2-dimensional gas chromatography coupled with simulated distillation to obtain quantitative distribution of monoaromatics, polyaromatics and saturated hydrocarbons. A quantification study of different types of carbons was performed by 13C NMR and showed the evolution of products. The nature of bio-liquid impacts slightly on the conversion and gas production but not on the selectivity of middle distillates and naphtha. This is explained by a decoupled hydrodeoxygenation and hydrocracking process. This also resulted in a high hydrodesulfurization conversion.

Covalent triazine frameworks (CTFs) are a class of porous organic polymers that continuously attract growing interest because of their outstanding chemical and physical properties. However, the control of extended porous organic framework structures at the molecular scale for a precise adjustment of their properties has hardly been achieved so far. Here, we present a series of bipyridine-based CTFs synthesized through polycondensation, in which the sequence of specific building blocks is well controlled. The reported synthetic strategy allows us to tailor the physicochemical features of the CTF materials, including the nitrogen content, the apparent specific surface area, and optoelectronic properties. Based on a comprehensive analytical investigation, we demonstrate a direct correlation of the CTF bipyridine content with the material features such as the specific surface area, band gap, charge separation, and surface wettability with water. The entirety of these parameters dictates the catalytic activity as demonstrated for the photocatalytic hydrogen evolution reaction (HER). The material with the optimal balance between optoelectronic properties and highest hydrophilicity enables HER production rates of up to 7.2 mmol/(h·g) under visible light irradiation and in the presence of a platinum cocatalyst.

Covalent Triazine Frameworks (CTFs) are a class of Porous Organic Polymers which attracts continuously growing interest because of their outstanding chemical and physical properties. However, the control of extended porous organic frameworks’ structures at the molecular scale for a precise adjustment of their properties has hardly been achieved so far. Here, we present a series of bipyridine-based CTFs synthesized through polycondensation, in which the sequence of specific building blocks is well controlled. The reported synthetic strategy allows to tailor the physicochemical features of the CTF materials, including nitrogen content, apparent specific surface area and opto-electronic properties. Based on a comprehensive analytic investigation, we demonstrate a direct correlation of the CTF bipyridine content with the material features such as specific surface area, bandgap, charge separation and surface wettability with water. The entirety of those parameters dictates the catalytic activity as demonstrated for the photocatalytic hydrogen evolution reaction (HER). The material with the necessary balance between opto-electronic properties and highest hydrophilicity enables HER production rates of up to 7.2 mmol·h-1·g-1 under visible light irradiation and in the presence of a platinum co-catalyst.

International audience; Bifunctional catalysis combining acidic catalysts and sulfide active phases is usually related to hydrocracking catalysts which balances the hydrogenation function of a NiMo (NiW) alumina supported sulfide catalysts and the acidic function of a zeolite. The discovery of sulfur-resistant catalysts for selective ring opening (SRO) is an important challenge for refiners, considering the future legislation on cetane index of diesel fuels. In the present work, we studied the properties of various transition metal sulfides (TMS) supported on Y zeolite in gas-phase decalin hydroconversion at high hydrogen pressure (5 MPa) in the presence of 0.8% H2S concentration. This screening shows high activities for noble metal based sulfides with a mechanism which proceeds by skeletal isomerization induced by the zeolite. Catalytic activity was improved by the use of ternary sulfides such as Ni1-xRuxS2 or NiRh2S4 on Y zeolites. High decalin conversion levels can be reached below 250°C with more of 20% of ring opening products and thanks to the use of comprehensive GC, a detailed mechanism of the SRO of decalin is given.

fff; International audience; Two-dimensional comprehensive gas chromatography is an established technique, employed for the characterization of complex samples. Broadband vacuum ultraviolet absorption spectroscopy detection has recently attracted a lot of attention as it is a universal detection technique characterized by good selectivity but also ease of use and amenability to coupling with two-dimensional comprehensive gas chromatography. Vacuum ultraviolet spectroscopy is particularly interesting due to the possibility of performing spectral decomposition for species that coelute in gas chromatography analysis. This detector has quantitative capabilities, however not all species absorb vacuum ultraviolet radiation the same. Unfortunately, vacuum ultraviolet relative response factors for compounds are not always available. Methods to rapidly measure vacuum ultraviolet relative response factors and generate a large database that would allow calibration free quantitative analysis of complex mixtures are therefore of great interest. In this work, a universal methodology that permits rapid measurement of vacuum ultraviolet relative response factors is reported. It involves flow modulated two-dimensional comprehensive gas chromatography with dual vacuum ultraviolet and flame ionization detection. In this set-up, flame ionization detection is employed as a quantitative reference allowing to scale vacuum ultraviolet responses of investigated compounds. This approach was validated by flow measurements and by comparing relative response factors obtained for model compounds with literature data.

International audience; Direct C–H functionalization catalyzed by a robust and recyclable heterogeneous catalyst is highly desirable for sustainable fine chemical synthesis. Bipyridine units covalently incorporated into the backbone of a porous organic polymer were used as a porous macroligand for the heterogenization of a molecular nickel catalyst. A controlled nickel loading within the porous macroligand is achieved, and the nickel coordination to the bipyridine (bpy) sites is assessed at the molecular level using IR and solid-state NMR spectroscopy. The heterogenized Ni-bpy catalyst was successfully applied to the direct and fully selective C2 arylation of benzothiophenes, thiophene, and selenophene, as well as for the arylation of free NH-indole. Recyclability of the catalyst was achieved by employing hydride activators to reach a cumulative turnover number of more than 300 after seven cycles of catalysis, which corresponds to a total productivity of 12 g of 2-phenylbenzothiophene, chosen as model target biaryl, per gram of catalyst.

International audience; Comprehensive two−dimensional Gas Chromatography with Vacuum Ultraviolet detection (GC×GC/VUV) results in sizable data for which noise and baseline drift ought to be corrected. As GC×GC/VUV signal is acquired from multiple channels, these pre−processing steps have to be applied to data from all channels while being robust and rather fast with respect to significant size of the GC×GC/VUV data. In this study, we describe advanced GC×GC/VUV data pre−processing techniques for noise and baseline correction that are not available in commercial softwares. Noise reduction was performed on both the spectral and the time dimension. For baseline correction, a morphological approach based on iterated convolutions and rectifier operations is proposed. On the spectral dimension, much less noisy and reliable spectra are obtained. From a quantitative point of view, mentioned pre−processing steps significantly improve signal to noise ratio for analyte detection and hence improve their limit of detection (circa 6 times in this study). These pre−processing methods were integrated into plug im! platform (https://www.plugim.fr/).

International audience; GC × GC is an advanced separation technique allowing to achieve quantitative and qualitative characterization of complex samples. In order to perform two-dimensional separation, the system must provide suitable peak modulation which will direct short impulses of first column flow towards the second column. Forward fill/ flush differential flow modulation is a cost effective and no cryogen requiring approach which allows modulation over a wide range of analytes with very different boiling points. However, optimization of the flow modulation process can be difficult to understand and quantification performance might be compromised if the parameters of the modulation process are not properly set. Modulated peak shape can be a good indication of the efficiency of the modulation process, however it is not sufficient to guarantee good quantification. Different average velocities in the beginning and the end of the thermally programmed GC run may cause different efficiency of the modulation process in various parts of the chromatogram. The purpose of this work is to investigate quantitative performance of the forward/fill flush modulation and delineate parameters that determine the effectiveness of the modulation process and its ability to properly reflect the quantitative composition of the investigated sample.

International audience; In this study, we evaluate and compare the photocatalytic degradation and mineralization of two alkylphosphates, the tributylphosphate (TBP) and the dibutylphosphate (DBP) in presence of TiO2 irradiated under UV-A. TBP and DBP are chosen because they are frequently present in nuclear reprocessing waste water, where they are used as extractant for cleaning and decontamination purposes. In the first part of the publication, we focus on the degradation of TBP by following its disappearance by GC-MS, the fate of phosphate by 31P NMR analysis and ionic chromatography, its mineralization by TOC measurement and finally the formation of carboxylic acid carbon by HPLC-UV. In the second part of the publication, we compare the kinetic of mineralization of TBP and DBP, the fate of phosphate by $^{31}$P NMR analysis and the nature and evolution of carboxylic acid. Our results show that DBP is an intermediate product of the degradation of TBP and that the nature carboxylic acid formed during the degradation of TBP and DBP are the same. We also show that mineralization process is consistent with the Langmuir-Hinshelwood model and independent of the nature of alkylphosphate.

People spend approximately 80% of their time indoor, making the understanding of the indoor chemistry an important task for safety. The high surface-area-to-volume ratio characteristic of indoor environments leads the semi-volatile organic compounds (sVOCs) to deposit on the surfaces. Using a long path absorption photometer (LOPAP), this work investigates the formation of nitrous acid (HONO) through the photochemistry of adsorbed nitrate anions and its enhancement by the presence of furfural. Using a high-resolution proton-transfer-reaction time-of-flight mass spectrometer (PTR-TOF-MS), this work also investigates the surface emissions of VOCs from irradiated films of furfural and a mix of furfural and nitrate anions. Among the emitted VOCs, 2(5H)-furanone/2-Butenedial was observed at high concentrations, leading to maleic anhydride formation after UV irradiation. Moreover, the addition of potassium nitrate to the film formed NOx and HONO concentrations up to 10 ppb, which scales to ca. 4 ppb for realistic indoor conditions. This work helps to understand the high levels of HONO and NOx measured indoors.

The molecular-level structuration of two full photosystems into conjugated porous organic polymers is reported. The strategy of heterogenization gives rise to photosystems which are still fully active after 4 days of continuous illumination. Those materials catalyze the carbon dioxide photoreduction driven by visible light to produce up to three grams of formate per gram of catalyst. The covalent tethering of the two active sites into a single framework is shown to play a key role in the visible light activation of the catalyst. The unprecedented long-term efficiency arises from an optimal photoinduced electron transfer from the light harvesting moiety to the catalytic site as anticipated by quantum mechanical calculations and evidenced by in situ ultrafast time-resolved spectroscopy.

RMN+ECI2D+DLA:CLO:CGE; International audience; The use of co-produced lignin from pulp industry or biorefinery gains nowadays a strong interest to produce aromatic compounds in a sustainable way. The valorization of those technical lignins faces their complex structure and the study of lignin conversion requires huge analytic development and careful mass and carbon balance effort during the conversion. Heterogeneous catalysts have proved to increase the liquefaction of lignin by solvolysis especially under hydrogen pressure. We report here the last results obtained for lignin valorization by catalytic hydroconversion, with a CoMo based sulfide catalyst, as a mean to depolymerize lignin and produce aromatic compounds. The originality is the use of a batch reactor opened on the gas-phase, with a continuous feeding of H2, a reflux/condensing system to remove continuously light products and water from the reacting mixture and recycle the solvent. The advanced reaction system has been demonstrated to be powerful compared to a traditional batch system previously used and allows to separate the deoxygenated monomers easily from the reaction mixture. The water formed was also successfully recovered in cold trap and quantified, and, we followed the gases formed online, which is important to get kinetic insights.

International audience; The valorization of lignin coming from pulp industry or bio-ethanol refineries into renewable chemicals is one of the great challenges of the biorefinery concept. Among the several processes proposed to depolymerize lignin, catalytic hydroconversion appeared efficient to get high liquid yield and can provide targeted aromatic monomers. A new semi-continuous set-up consisting in a batch reactor opened on the gas-phase was implemented to carry out the catalytic lignin liquefaction into phenolic and deoxygenated aromatic compounds with continuous H2 feeding. The interest of this equipment is the continuous removing of light products and water from the reacting mixture whereas the hydrogen donor solvent is reintroduced in the reactor via a reflux/condensing system. A Co-promoted Mo sulfide catalyst was used and thanks to efficient separation and extensive analysis, the components of the different gaseous, liquid and solid fractions obtained were identified and quantified. The evolution of the various fractions in function of the time and the deep investigation of the composition, allowed to propose a reaction scheme for the lignin depolymerization in those operating conditions.

RMN+ECI2D+LPI:DLA:CLO:CGE; International audience; The discovery of sulfur-resistant catalysts for selective ring opening (SRO) is an important challenge for refiners, considering the future legislation on cetane index of diesel fuels. In the present work, we studied the properties of RuS2 supported on several zeolites in gas-phase decalin hydroconversion at high hydrogen pressure (5 MPa) in the presence of 0.8% H2S concentration. Catalytic bifunctionality was investigated by changing the Ru loading or support acidity. The addition of RuS2 strongly improved catalytic activity of an HY zeolite, decreased coke deposition and dehydrogenation and increased selectivity towards RO products. The mechanism mainly proceeds from skeletal isomerization induced by the acidity of the zeolite but the hydrogen activation properties of RuS2 are beneficial to the activity and stability of the catalyst.

Oxidation of finely divided molybdenum sulfide in ambient air has been studied for air exposure times from 10 min to 1 year to clarify the nature of the reaction products and the mechanistic steps....

In this work, alkaline earth phosphates have been prepared by co-precipitation and evaluated in gas phase dehydration of ethyl lactate to acrylic acid and ethyl acrylate. These solids, which were previously shown to be active for the dehydration of lactic acid, appeared more efficient. Indeed, it was shown that the decarbonylation/decarboxylation route leading to acetaldehyde was strongly inhibited compared to conversion of lactic acid and molar selectivity values to dehydration products reaching 87% were obtained. Furthermore, it was shown that the deactivation of the catalysts could strongly be slowed by addition of water vapor to the feed. The reaction pathways have been studied in the presence and absence of water and it was shown that acrylic acid was mainly formed by a simultaneous dehydration/hydrolysis reaction. The characterization of the catalysts surface from the results of XPS, cross polarization NMR, DRIFT and TEM showed the presence of a surface amorphous layer containing POH species. In situ DRIFT measurements have revealed that formation of POH groups was favored under water vapor and that these species interacted with reactants or reaction products at the reaction temperature.

H4SiW12O40 heteropolyanions, WO3, TiO2 and SnO2 were supported over SiO2 at high loading by wet impregnation or grafting methods and evaluated in the dehydration of isobutanol to butenes. Their structural and textural properties were determined by different techniques such as XRD, TEM, IR, XPS and N2 liquid physisorption respectively. Most of the prepared compounds contained amorphous oxide clusters of few nanometers lying over SiO2 and were mesoporous. Their acidic properties (nature, density and strength) were investigated by pyridine and CO adsorption followed by FTIR. H4SiW12O40/SiO2 contained strong Bronsted acid sites while mostly moderate Lewis acid sites were present on TiO2/SiO2 and SnO2/SiO2. WO3/SiO2 had a mixed character with both moderate Bronsted and Lewis acid sites. The catalytic activity was related to the Bronsted acidity and the best selectivity to butenes close to 100% were obtained for the catalysts containing moderate and weak sites (WO3/SiO2 and TiO2/SiO2). Except for SnO2/SiO2 catalysts, which were unstable and unselective to dehydration products, a significant selectivity to linear butenes (ca 30%) was obtained with all the catalysts. It is proposed that this isomerisation activity is mainly related to the equilibrium between carbocations formed after E1 elimination of water. Its slight increase for H4SiW12O40/SiO2 (and to a lesser extent WO3/SiO2) was attributed to strong Bronsted acid sites able to catalyse the isomerization of isobutene to linear butenes.

Selective ring opening is an important hydrotreating process for gas oil upgrading. In this work, we have used an Ir/NaY bifunctional catalyst -highly efficient in sulfur-free conditions- as a reference system to assess the effect of H2S impurity concentration (0–1 %) on the kinetics and mechanisms of naphthene conversion under high hydrogen pressure (5 MPa). Three model naphthenic molecules (decalin, perhydroindan and butylcyclohexane) were compared to evaluate the influence of the ring size (C5 vs C6) and number (1 vs 2). The numerous reaction products were identified, quantified and classified by using two-dimensional gas chromatography (GC × GC). In the absence of sulfur, it is confirmed that C5 rings are opened faster than C6 rings, and that single-ring naphthenes are converted faster than double-ring naphthenes. The presence of H2S, even at concentrations as low as 30 ppm, drastically and irreversibly changes the dominant catalytic function (from metallic to acidic), mechanism (from dicarbene-mediated to carbocation rearrangement) and family of products (from ring-opening products to skeletal-isomerization products). Together with experiments at variable reactant conversion, these results allow us to propose mechanistic reaction schemes for the three naphthenes under similar conditions, both for sulfur-free and sulfur-rich atmospheres.

RMN+ECI2D:ING+AMR:CLO:NOG:CMI:CGE:DLA:YSC; International audience; Fast pyrolysis of biomass yields bio-oils with high levels of oxygen-containing components, high acidity and low stability. Further upgrading of these oils is necessary before they can be used as liquid fuels. Several low-cost strategies have been proposed for reducing the oxygen and acid contents. Catalytic conversion of pyrolytic vapors allows a partial deoxygenation before vapor condensation. In this context, a semi-continuous pyrolysis test combined with a catalytic reactor was built and different acid catalysts were tested. The resulting bio-oils were characterized in depth to get more insights in the role of the catalyst on bio oil vapors conversion.

International @ RAFFINAGE+RHE:MTF:PAF:CLO; International audience; A new approach has been developed to characterize bifunctional catalysts in a complex matrix of hydrotreated vacuum gas oil, 370°C+ using a batch reactor test. Triphasic reactions were carried out in a reactor equipped with a stationary basket, hydrogen injection and products sampling systems. Bifunctional catalysts containing different relative amounts of alumina-supported NiMo sulfide and zeolite were tested at 400°C under 120 bars over different reaction times. The repeatability of the test conditions was validated and the lack of mass transfer limitations at phase interfaces was confirmed. Gas and liquid samples were analyzed by one and two-dimensional gas chromatography (2D-GCGCxGC) respectively to obtain quantitative distributions of linear and branched paraffins, olefins, naphthenes and aromatics. The details of the products distribution provided by the chromatography were analyzed using model kinetic mechanisms of bifunctional catalysis. It has been established that the limiting step defining the total conversion is scission of the hydrocarbon chains on zeolite sites. The increase of the molybdenum to zeolite ratio provided an improvement of selectivity to middle distillate (150-370°C)

International audience; Since the beginning of the 2000's, comprehensive GC x GC chromatography brought a totally new way to characterize complex matrices. This disruptive technique is well adapted to fuels and rapidly gained importance in R & D laboratories of oil (and related) companies. Therefore, this analytical tool has been applied to many aspects of refining and especially the challenge of reducing the sulfur content in fuels. The present article reviews the use of comprehensive GC x GC for understanding the nature of sulfur compounds in refinery products (from gasoline to VGO) and their catalytic conversion through various catalytic processes such as HDS, AOTS, ODS. Various types of detectors (universal or specific) as well as FIT GC x GC have been applied and can be combined in order to get a better description of the S compounds in oil products.

RMN+ECI2D+CLO:CGE; International audience; Analytical multidimensional gas chromatography (MDGC) and more recently comprehensive GC (GCxGC) provide a unique understanding of complex matrix such as fuels. The approach to GC×GC was introduced and pioneered by Phillips et al.[1] in the mid 90’s. Since that time, tremendous developments have been made in the development of modulators (cryogenic or micro-fluidic) and coupling with many types of detectors leading to a unique description of complex mixtures such as oil, fuels, fragrance, flavours, … In the field of petroleum industries, companies developed many applications and are now using GCxGC as a routine technique [2]. We will summarize selected applications of GCXGC linked to hydrotreatments or desulfurization processes as well as hydroconversion. After a brief introduction on the fundamentals of GXGC, we will illustrate here the benefit of this technique for kinetics and the characterization of light fuels (gas oil, gasoline …) during desulfurization (HDS of SRGO, co processing HDO/HDS, OATS) or cetane improvement by SRO.

Ferrospinels with different metals—Fe, Ni, Co, and Cu—were investigated as oxygen ion and electron carrier materials for the chemical-loop reforming of ethanol, aimed at the production of H2 with intrinsic separation from CO and CO2. The materials used showed different behaviours both during the first step of the loop—the reduction of the annealed spinel with ethanol—and the second step—the re-oxidation with steam—as well as with the increasing cycle number. The differences shown were rationalised in terms of redox behaviour, carbon residue accumulation during the cycle, and ability to restore the starting spinel structure during cycling. Mixed ferrospinels showed enhanced reducibility when compared to magnetite; however, since coke accumulation was unavoidable, the best-performing material amongst the materials tested was Co ferrite, which underwent the greatest reduction and was able to maintain it throughout repeated cycles.

International audience; Comprehensive two-dimensional gas chromatography (GC × GC) is a powerful technique for analyzing mixtures of hundreds of hydrocarbons. In the context of fuel upgrading through selective ring opening, we propose a methodology for GC × GC analysis of complex mixtures resulting from the hydroprocessing of a single model gas oil compound, decalin, over two different types of bifunctional catalysts based on a transition-metal sulfide (NiWS on amorphous silica–alumina) or a noble metal (Ir on La,Na–Y zeolite). The reactions lead to several products families, the dominant ones being ring-opening products (ROPs) and skeletal-isomerization products (SkIPs). First, it is shown that the ROP distribution can be characterized in terms of isomerization degree by using the cumulative distribution function of the GC × GC (GC Image) software. Second, in a more quantitative approach, the products families have been subdivided into chemical groups, according to the isomerization degrees of the individual compounds, which were almost all tentatively identified by two-dimensional gas chromatography coupled with mass spectrometry (GC × GC-MS) through the use of literature data. This allows us to thoroughly analyze the influence of the catalyst nature and the presence of H2S in the reactant feed on the products distribution, and thereby gain insight into the mechanism of decalin hydroconversion over bifunctional catalysts. In particular, it is shown that metal sulfidation suppresses the metal-catalyzed C–C hydrogenolysis pathway at the benefit of undesirable acid-catalyzed isomerization steps. The methodologic work presented here for decalin is believed to be applicable to other bicyclic (naphthenic or aromatic) compounds.

RMN+ECI2D+BJF:MNG:DLA:CLO:CGE; International audience; The hydroconversion of a wheat straw soda lignin was studied in a batch reactor, in tetralin solvent, with a NiMoS/Al2O3 catalyst under H-2pressure at 350 degrees C. Gaseous, solid and liquid products wereseparated, quantified and detailed analyses were performed in order todescribe and to understand the various reactions occurring versusresidence time. In those operating conditions, the weakest beta-O-4 andalpha-O-4 ether linkages of the lignin were first cleaved. The ligninwas thus progressively converted into smaller hydrogenated anddeoxygenated fragments called lignin residues which were extensivelycharacterized by GPC and NMR. In the liquid phase, smaller monomers anddimers were identified by GC x GC/MS and quantified by GC x GC/FID. Theevolution of these molecules was investigated as a function of residencetime in order to investigate the catalytic transformation scheme oflignin. (C) 2015 Elsevier B.V. All rights reserved.

RMN:XPS+ECI2D+CLO:PDE:JMI:SLO; International audience; IntroductionAcrylic acid is a key platform molecule whose main applications are superabsorbent polymers (diapers), paints, coatings, adhesives and flocculating agents for water treatment. It is produced at 4.5 Mt/year by selective oxidation of propene, whose price is growing quickly because of increasing demand and rarefaction of petroleum. Several alternative sustainable routes are investigated at the present time. Among them, dehydration of lactic acid and lactates are interesting since these reactants can be yielded both by dehydrogenation of glycerol, a by-product of bio-diesel production and directly by fermentation of sugars.In spite of first study in 1958 [1], dehydration of lactic acid (LA) and derivatives have been mostly investigated since recent years with the rise of biomass valorization. High yields to acrylic acid (AA) and derivatives were obtained using modified zeolites [2] or calcium phosphates [3-4]. However, zeolites suffer from hydrothermal instability.In this work, different alkaline earth phosphates were prepared and evaluated for dehydration of lactic acid to acrylic acid. Because of high LA reactivity, the ethyl lactate (EL) conversion was also investigated. The origin of catalytic efficiency was explained from acido-base properties and the nature of the active sites present in such catalysts. Materials and MethodsAlkaline earth ortho, pyrophosphates and hydroxyapatites were prepared by co-precipitation method. Their labeling was described elsewhere [5]. The solids were characterized by XRD, FTIR spectroscopy, BET measurements and ICP analysis. Furthermore, surface characterization was obtained crossing XPS, 1H-31P CP-MAS NMR, TEM and IR techniques. Acid-Base properties were measured by NH3/CO2-TPD respectively and adsorption of probe molecules followed by FTIR. Gas phase dehydration of ethyl lactate or lactic acid was conducted in a fixed bed reactor at atmospheric pressure. Solutions of reactant were vaporized at 160-170°C and diluted with N2 before sending to the top of the reactor. After trapping, the condensed molecules were analyzed off-line with a GC chromatograph while gas products were analyzed on line. Results and DiscussionIn first step, the influence of reaction parameters was investigated: selectivity to acrylic acid strongly depends on the reaction temperature but not on the contact time. At optimized temperature of 380°C, values ranging from 19 to 49% were measured for the different prepared phosphates catalysts that are stable for at least 24 h. The best yield (43%) was obtained from barium orthophosphate [5]. Acid–base properties determined from NH3 and CO2 TPD measurements revealed that such phosphates contain high proportion of acidic and basic sites with same weak strength. Furthermore, correlation between selectivity to acrylic acid and the acid–base balance was clearly established: it was 50% for balance close to 1 and decreased increasing this parameter [5]. Dehydration of ethyl lactate appeared as promising reaction in spite of lower conversions. Indeed, selectivity values in dehydration products (AA and ethyl acrylate (EA)) were much higher with maxima of 87%. The evolution of selectivity sets with the conversion revealed that AA is mainly formed by simultaneous dehydration/hydrolysis reaction. However, the catalysts were unstable vaporizing pure EL solution because of polymerization of EA leading to coke formation. Interestingly, it was shown that deactivation can be inhibited adding water to the gas phase [6]. XPS characterization of the catalysts evidenced the presence at the surface of P-rich phase that corresponds to amorphous overlayer of few nanometers as evidenced by TEM. From XPS, 1H-31P CPMAS and DRIFT spectra, it was concluded that such phase contains high quantity of POH species and could correspond to a mixture of mono and dihydrogenophosphates or polyphosphates. In situ DRIFT spectra have revealed that POH species are formed under water vapor whereas they are consumed or modified under reaction mixture for both reactants suggesting that they involved in one step of the reaction mechanism. Finally, NH3 and CO2-TPD measurements followed by in situ DRIFT spectroscopy revealed that acid base pairs (M2+; P=O) and P=O basic sites are respectively probed by these techniques. The acid-base balance of 1 obtained for the most selective catalysts was explained by the involvement of (M2+; P=O) pairs in the rate-determining step of the reaction mechanism. Finally, the monitoring of POH isotopic labeling under reaction feed revealed proton transfer to the methyl group of lactic acid. From all these results, it was proposed that (M2+; P=O) pairs would constitute the adsorption site of lactic acid which then dehydrate in acrylic acid by an E2 mechanism involving POH species. ConclusionsSelectivity to acrylic acid is limited for dehydration of lactic acid over alkaline earth phosphates. Very high selectivity to dehydration products can be obtained using ethyl lactate as reactant but high specific surface area is required to reach high yield. Water vapor has to be added to the reaction feed in good proportion to avoid catalyst deactivation and reactant hydrolysis leading to lower selectivity. Finally, crossing different techniques and from in situ experiments, it was proposed that (M2+; P=O) pairs are the active and selective sites in such catalysts. These findings will allow designing more efficient catalysts.Acknowledgements This work was supported by French ANR Program Chimie Durable – Industries – Innovation (CD2I) GALAC, a joint project between IRCELYON, UCCS, LC/ENS-Lyon and Novance company.References [1]R.E. Holmen, US Patent 2859240, 1958.[2]J.Zhang, Y.Zhao, M. Pan, X. Feng, W. Ji, C. Au, ASC Catal., 1 (2011) 32.[3]J. H. Hong, J.-M. Lee, H. Kim, Y. Kyu Hwang, J.-S. Chang, S. B. Halligudi, Y.-H. Han, App. Catal A, 396 (2011) 194.[4]V.C. Ghantani, S.T. Lomate, M.K. Dongare and S.B. Umbarkar, Green Chemistry, 15 (2013) 1211.[5]E. Blanco, P. Delichere, J.M.M. Millet, S. Loridant, Catal. Tod. 226(2014)185–191.[6]E. Blanco, P. Delichere, C. Lorentz, L. Burel, C. Pinel, M. Vrinat, J.M.M. Millet, S. Loridant, Appl. Catal. B : Environm.,180 (2016) 596.

RMN+ECI2D+CLO:PDE:JMI:SLO; National audience; Acrylic acid is one of the major petrochemical intermediates. In near future, its production from renewable resources is required by clean process. Dehydration of lactic acid to acrylic acid corresponds to one of the alternative routes to investigate. In the present work, alkaline earth phosphates have been prepared and evaluated for this reaction and also dehydration of ethyl lactate to acrylic acid and ethyl acrylate that appeared as more interesting. Moreover, the reaction mechanisms were determined focusing the effect of water. Furthermore, a correlation between catalytic and acido-base properties was established. Finally, the active sites, selective or not, were identified from numerous techniques including in situ DRIFT spectroscopy.

International @ ECI2D+DLA:CLO:CGE; International audience; Because of environmental concerns and needs for energetic independence, the transformation of lignocellulosic biomass is deeply investigated in order to provide biofuels and chemicals in a near future. Lignin, which represents almost 30% of this biomass, is a macromolecule containing mainly phenyl-propane units with ether linkages, its exact structure being strongly dependant on the vegetal source and on the extraction process. The total lignin availability exceeds 300 billion tons and continues to increase annually. Each year, more than 50 million tons of lignin are co-produced in pulp industry and burned as a low-value fuel. It has been established that a non-negligible part of this lignin can be used for other applications without weakening this industry. In addition, the improvement of the pulping processes, the production of cellulosic ethanol and new patented processes towards highly pure sulfur-free lignins should provide even greater quantities of high grade materials. The use of lignin as a precursor of hydrocarbons or phenolic compounds has then gained a strong interest due to its low cost and high availability. In order to get valuable bio-liquid from lignin, catalytic hydroliquefaction in hydrogen-donor solvent was proposed. High liquid yields were claimed but the mass balance and the identification of all the products and lignin residues were not clearly described. We report here the experimental results obtained in the hydroconversion of wheat straw soda lignin under hydrogen pressure in the presence of a supported catalyst, with tetralin as solvent in a batch reactor. The catalytic hydroconversion of the lignin reached 82 wt% with a high mass balance (>96 wt%) and with 71 wt% liquid yield. The lignin residue was converted until reaching 9 wt% of the starting lignin while the solids yield was decreasing until reaching initial ashes content. The size of the lignin, evaluated by GPC, diminished gradually from 26 units to 6 units after 28h, mainly by ether cleavage (B-O-4 linkages). By the same time, the aliphatic hydroxyl, carboxylic and methoxy groups were removed as observed by NMR. The GCxGC-MS analysis of the liquid fractions allowed the deep identification of the monomers families, including phenolic compounds, aromatics, naphthenes and alkanes. In each family the C1 to C6 alkyl-substituted derivatives were detected and quantified thanks to a FI detector. All those results allowed us to propose a reaction pathway for the overall transformation of the lignin on NiMo-based catalysts. It appeared that some specific chemical functions like aliphatic hydroxyl or carboxylic acids, exhibited a high reactivity during the reaction while syringyl units are progressively transformed in guaiacyl, catechol and phenolic units and then aromatics and naphthenic derivatives following the well-known reaction scheme described for guaiacol HDO. In addition, after 28h of use, the catalyst can be recycled.

XPS:RMN+ECI2D+LMA:CLO:PAF:JMI; International audience; Four preparation methods have been developed for the synthesis of lanthanum orthophosphate catalysts, which are shown to be active and selective catalysts for the dehydration of light alcohols (C-2 to C-4). Their crystallinity, surface area, surface composition and acid-base properties appear to differ according to the preparation method used. The most important parameter influencing their catalytic properties appears to be their surface composition since this has a direct influence on their surface acidity. All of the solids presented weak and moderately strong Bronsted and Lewis acid sites, and only weak basic sites in low quantities. These acid-base properties resulted in the prevalence of an E-1-type mechanism for 1-butanol dehydration. Bronsted acid sites, which appear as the most efficient sites, are associated with the presence of an excess of phosphorus at their surface and from spectroscopic data this is attributed to (H2PO4)(-3+n) (n=1 or 2) species from spectroscopic data. The prevalence of these species and their optimum surface distribution make them extraordinarily efficient and ultra-selective for the dehydration of several alcohols. Published by Elsevier B.V.

Drastic regulations concerning sulfur content in fuels require the development of new processes in the refineries. In the case of gasoline, AOTS process based on the alkylation of thiophene by butenes was proposed. In the present work, we attempted to describe the mechanism of such a reaction with model molecules. Liquid-phase alkylation of 3-methylthiophene with 2-methyl-2-butene was performed on supported phosphoric acid. It is shown that this reaction is mainly selective to monoalkylation products. The kinetics is following an Eley–Rideal law and the reaction intermediate seems to be an ester of phosphoric acid or polyphosphate.

The mechanisms of formation of the three-dimensional titanium phosphate πTiP and of H−TiP, a hexagonal mesotextured titanium(IV) fluorophosphate, were studied using in situ and ex situ 19F and 31P NMR experiments. In situ NMR indicated that the prenucleation building units (PNBU), forming the solids under hydrothermal conditions, are identical for both phases. A possible structure of the PNBU is provided. Ex situ 19F and 31P liquid NMR allowed the transformations occurring in the supernatant liquid to be followed. Two kinds of species were observed during both syntheses: reactive primary species, which are the less fluorinated titanium fluorophosphates, and passive primary species, that is, the highly fluorinated titanium fluorides and fluorophosphates, which act as a reservoir of reactive primary species by slow interconversion. πTiP crystallizes following a condensation, precipitation, dissolution, and re-crystallization process as shown by quantitative analysis of ex situ NMR of the solid state and X-...

RMN+CDFA:ECI2D+VAE:TSN:DLA:CLO:MTF:CGE:PFO; International audience; None

RMN+ECI2D+CLO:CGE; International audience; Comprehensive two-dimensional GC is a powerful technique that can be used to separate very complex mixtures such as those found in the hydrocarbon processing, perfums, . Petroleum industry is an important application area for GCxGC. It is now routinely applied in R&D refining groups for the characterization of ligh fuels (gasoline, gas oil). In addition, flow modulation offers a viable alternative to thermal modulation without the burdens imposed by cryogenic requirements for comprehensive GCxGC. If cryogenic trapping is the reference technique for volatile and semi volatile compounds, it may be a drawback for heavy molecules such as polycyclic aromatic hydrocarbons on long chains alkanes which are difficult to volatilize after cryo trapping. We have enlarged the field of application of GC X GC using the differential flow modulator (DFM) to work on heavier feddstocks. The first results obtained were first under normal GC conditions were in good agreement with data coming from a cryogenic system. The differential flow modulator was installed on a GC FID 7890A Agilent for High Temperature GC. Acquisition and treatment of the detector signal were performed with the Agilent Chemstation, the data were transferred to GC-Image software (ZOEX) for data processing. The calibration of the system with paraffinic compounds demonstrates that paraffins up to C60 can be analyzed. Thus DFM GCxGC- FID technique was applied to the characterization of atmospheric residues, converted atmospheric residues or coal liquids. The GCxGC technique allowed discriminating between saturated and aromatic compounds with well identified families from mono- up to pentaromatic compounds.

Aqueous solutions of titanium(IV) fluorides and fluorophosphates were studied by 19F and 31P NMR for variable F/Ti and (F + P)/Ti ratios. The species distribution is described as successive complexation equilibria. For the Ti/F binary system, equilibrium constants were determined for TiOF(H2O)4+, TiF5(H2O)-, and TiF62- and estimated for TiOF2(H2O)3, TiF3(OH)(H2O)2, and TiF4(H2O)2. Previously reported anionic species are confirmed and for the first time the spectral signatures of TiOF(H2O)4+, TiOF2(H2O)3, and TiF3(OH)(H2O)2 are provided. Fluorophosphates complexes were observed, and several species containing fluorides and phosphates were identified. These species are representatives of the primary building units during hydrothermal synthesis of nanoporous and mesoporous materials.

International @ RAFFINAGE+EBL:PDE:CLO:LBU:JMI:SLO; International audience; Acrylic acid (AA) is a platform molecule produced at 4 Mt/year by selective oxidation of propene, whose price is growing quickly because of increasing demand and rarefaction of petroleum. An alternative green route consists in dehydration of lactic acid (LA) that can be produced by dehydrogenation of glycerol [1]. High yields to acrylic acid were obtained using modified zeolites [2] or calcium phosphates [3-4]. In the present work, alkaline-earth pyrophosphates (MPP) and orthophosphates (MOP) were prepared, evaluated both for gas phase dehydration of LA and ethyl lactate (EL) and the origin of the catalytic efficiency was investigated crossing various techniques. The characterization of the most efficient catalysts showed that a thin amorphous layer of alkaline-earth phosphates was present over crystalline orthophosphates and pyrophosphates. Hydroxylated phosphorous species present in such layer were shown to be active for LA and EL conversion. This leads to the conclusion that the same reaction mechanism might be involved although different catalytic performances were obtained. These differences could arise from water vapor effect.