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The current work studies the reductive catalytic depolymerization (RCD) of lignin from a novel semi-industrial process. The aim was to obtain aromatic mono-, di-, tri-, and tetramers for further valorization. The substrate and products were characterized by multiple analytical methods, including high pressure size-exclusion chromatography (HPSEC), gas chromatography-mass spectrometry, GC-flame ionization detector (FID), GC-FID/thermal conductivity detector (TCD), and NMR. The RCD was studied by exploring the influence of different parameters, such as lignin solubility, reaction time, hydrogen pressure, reaction temperature, pH, type and loading of the catalyst, as well as type and composition of the organic/aqueous solvent. The results show that an elevated temperature, a redox catalyst, and a hydrogen atmosphere are essential for the depolymerization and stability of the products, while the reaction medium also plays an important role. The highest obtained mono- to tetramers yield was 98% and mono- to dimers yield over 85% in the liquid phase products. The reaction mechanisms influenced the structure of the aliphatic chain in the monomers, but left the phenolic structure along with the methoxy groups largely unaltered. The current work contributes to the development and debottlenecking of the novel and sustainable overall process, which utilizes efficiently all the fractions of wood, in line with the principles of green engineering and chemistry.

International audience; Women are increasingly present in the field of engineering, and despite a significant female presence, it has been found that the programmes continue to make no reference to women scientists. In chemical engineering, for example, all the names of scientists mentioned in the programmes belong to men only. To test this hypothesis of the overrepresentation of men in the programmes, a series of random opinion surveys were launched among 600 students from 5 universities to find out whether they had noticed this over-representation and what they thought about it. The results showed that the vast majority did not realize that the scientists presented as examples in classes were all men. In fact, 90% of the student panel were unable to identify a woman in the chemical engineering field, and the remaining 10% could cite only one or two-who were among the most recent and had received most attention from the media. The issue of inequalities between girls and boys and between women and men in education remains central to understanding and combating gender inequalities and to enabling people to develop as persons free from the limitations imposed on them by gender stereotypes. However, these inequalities cannot be explained exclusively by the issue of access to education but must also take the type and content of education into account. This article is a call for reflection on the content of university curricula and has a twofold objective: on the one hand, to raise awareness of this imbalance in representation among students, both male and female, and, on the other hand, to launch reflection on this "invisibility of women" and to propose some avenues for debate.

The synthesis of γ-valerolactone (GVL), a platform molecule that can be produced from lignocellulosic biomass, was performed in this work by hydrogenation of an alkyl levulinate over Ru/C. Kinetic models reported in the literature are typically not compared with rival alternatives, even if a discrimination study is needed to find the optimum operating conditions. Different surface reaction kinetic models were thus considered in this work, specifically addressing hydrogenation of butyl levulinate to GVL, where the latter was used as a solvent to minimize potential solvent interference with the reaction, including its evaporation. The Bayesian approach was applied to evaluate the probability of each model. It was found that non-competitive Langmuir-Hinshelwood with no dissociation of the hydrogen model has the highest posterior probability.

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International audience; The use of lignocellulosic biomass in the chemical industry has increased due to its non-competition with the food sector. Several platform molecules can be produced from this biomass. Among them, levulinic acid and its esters have been produced on an industrial scale. There are some reviews on the production of levulinic acid (LA) but few on the production of levulinates (LEs). To fill this gap, this review was written by also considering the environmental aspects. In the first stage, recent progress in the production of these platform chemicals was discussed. Production processes of alkyl levulinates from levulinic acid esterification, precursors (HMF, furfural, etc.), sugar monomers (glucose, fructose, etc.), cellulose, hemicellulose, or cellulose directly from lignocellulosic biomass were described. In the second stage, process separation and purification of LA and LEs were discussed. The final stage proposed an economic and environmental consideration for the production of these chemicals.

The production of platform molecules from the valorization of lignocellulosic biomass is increasing. Among these plateform molecules, γ-valerolactone (GVL) is a promising one and could be used for different industrial applications. This molecule is synthesized from levulinic acid (LA) or alkyl levulinates (AL) through a tandem hydrogenation/cyclization (lactonization) cascade. A lot of investigations have been carried out to develop the best catalyst for the hydrogenation step by using solely LA or AL. However, one should keep in mind that in the AL production via fructose alcoholysis, there is also LA production, and both are present in the product mixture during the further conversion. To the best of our knowledge, no article exists describing the hydrogenation of LA and AL simultaneously in one-pot. Also, the literature reporting the use of solid catalyst for the second cyclization step is rare. To fill this gap, the hydrogenation of levulinic acid and butyl levulinate was studied over Ru/C and Amberlite IR-120. Several kinetic models were evaluated via Bayesian inference and K-fold approach. The kinetic assessment showed that a non-competitive Langmuir-Hinshelwood with no dissociation of hydrogen where LA, BL and H2 are adsorbed on different sites (NCLH1.2) and non-competitive Langmuir-Hinshelwood with dissociation of hydrogen where LA, BL (butyl levulinate) and H2 are adsorbed on different sites (NCLH2.2) are the best model to describe this system. The presence of LA and Amberlite IR-120 allows to increase the kinetics of cyclization steps, and in fine to accelerate the production of GVL.

Xylan obtained from birch (betula pendula) by a novel semi-industrial scale aqueous based method was used for studying the hydrolysis and consecutive hydrolysis-hydrogenation processes in continuous reactors. Dowex 50WX2-100 was chosen as the hydrolysis catalyst based on the results of catalyst screening performed previously in batch reactor. It was also observed to perform well in continuous reactor converting xylan to xylose in high yield under the studied reaction conditions. The influence of several reaction parameters were investigated for optimization. Similar experimental conditions used in the hydrolysis were then applied for studying one flow through hydrolysis and hydrogenation of the semi-industrial xylan. A consecutive catalyst bed consisting of ruthenium on carbon was introduced into the continuous reactor downstream from the hydrolysis bed to hydrogenate monosaccharides to xylitol. Hydrogen was co-fed into the reactor with the xylan solution. Reaction parameters, including temperature, residence time and hydrogen pressure, were varied to maximize the xylitol yield. The developed continuous process was demonstrated to be highly selective and efficient for the valorization of the semi-industrial xylan by yielding over 90% xylitol under optimal experimental conditions. It was noticed, that co-feeding hydrogenation decreased the degradation of monosaccharides during hydrolysis, thus improving the selectivity towards the target product and enabling remarkable process intensification. Moreover, mathematical modelling was performed for the hydrolysis and one flow through hydrolysis and hydrogenation processes. The models take into account the consecutive reaction pathways and the influence of the experimental conditions. Good fits of the model to the experimental data were obtained. The conversion of this novel, well characterized wood-based xylan to produce xylose or xylitol in continuous reactors has not been studied previously. The current work contributes significantly to understanding the processing of real feedstock in one flow through employing consecutive reactions and provides necessary data for process intensification.

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International audience; Biomass valorization to chemicals, biofuels or materials will be more and more important during this century. Production of γ-valerolactone (GVL) from the hydrogenation of levulinic acid is a good illustration of this tendency. GVL can also be produced from alkyl levulinates hydrogenation. Can we find a relationship between the structure and the kinetics of this reaction? Can we predict the kinetics of any alkyl levulinates by knowing the kinetics of another alkyl levulinate? This paper has studied these two questions by developing a kinetic model including the effect of gas-liquid mass transfer. We have demonstrated that the kinetics of hydrogenation of levulinic acid, methyl, ethyl and butyl levulinates to GVL using Ru/C follow the Taft equation, which is derived from Linear Free Energy Relationships. This equation measures the effects of polar and steric on a reaction series. We have demonstrated that polar effect of the reaction series is the most significant effect. This relationship can predict the values of kinetic constants just by knowing their structure.

International audience; Epoxidation of oleic acid by peracetic acid (PAA) was studied in a recycled reactor system under conventional heating and microwave irradiation. This reaction system consists of several steps. Thus, a kinetic modelling strategy to diminish the number of parameters to be estimated was developed by investigating each reaction step: PAA synthesis and decomposition, epoxidation and ring-opening. The energy balance for microwave heating was correlated with the concentration of the microwave-absorbent species and the total input power of the microwaves. The epoxidation reaction was conducted in the vigorously stirred tank reactor under isothermal conditions within a temperature range of 50–70 °C. The organic phase content was 32–45% v/v. The interfacial mass transfer was supposed to be faster than the intrinsic reaction kinetics suppressing the use of mass transfer correlations. Nonlinear regression was used to estimate the kinetic parameters. Two models were developed for microwave and conventional heating respectively. The perhydrolysis showed to be the slowest reaction, followed by the epoxidation and the ring-opening. The use of microwave irradiation resulted in considerable process intensification for the epoxidation process. By employing microwave heating, the perhydrolysis step in the aqueous phase was enhanced, and the reaction time was reduced by 50% in best cases, which implies that the reactor size can be diminished by microwave technology.

International audience; The use of hydrogen peroxide as an oxidizing agent becomes increasingly important in chemistry. The example of vegetable oil epoxidation is an excellent illustration of the potential of such an agent. This reaction is traditionally performed by Prileschajew oxidation, i.e., by the in situ production of percarboxylic acids. Drawbacks of this approach are side reactions of ring-opening and thermal runaway reactions due to percarboxylic acid instability. One way to overcome this issue is the direct epoxidation by hydrogen peroxide by using γ-alumina. However, the reaction mechanism is not elucidated: does hydrogen peroxide decompose with alumina or oxidize the hydroxyl groups at the surface? The kinetics of hydrogen peroxide consumption with alumina in homogeneous liquid and heterogeneous liquid-liquid systems was investigated to reply to this question. Bayesian inference was used to determine the most probable models. The results obtained led us to conclude that the oxidation mechanism is the most credible for the heterogeneous liquid-liquid system.

A cyclic Ti32-oxo-cluster (CTOC)/BaTiO3/CuS three-layer heterojunction material that can effectively use visible light and vibration energy for photo-piezoelectric synergistic catalytic degradation of pollutants was synthesized by hydrothermal and ultrasonic methods. Under the conditions of visible light irradiation and mechanical vibration, the three-layer nanomaterial showed a tetracycline decomposition rate that reached ∼100 % within 60 min, which is higher than the degradation rate of 55.67 % and 45.2 % found for photocatalysis and piezoelectric catalysis, respectively. The piezoelectric material BaTiO3 inserted between the p-type CuS and the n-type CTOC can generate a polarized electric field under the action of an external force to promote the separation and migration of photo-generated carriers of the photocatalytic material, and achieve photo-piezoelectric synergistic catalysis effect. This work demonstrates the feasibility of combining photocatalytic technology with a piezoelectric effect, and provides a promising strategy for the development of photocatalytic materials.

International audience; The epoxidized group, also known as the oxirane group, can be considered as one of the most crucial rings in chemistry. Due to the high ring strain and the polarization of the C–O bond in this three-membered ring, several reactions can be carried out. One can see such a functional group as a crucial intermediate in fuels, polymers, materials, fine chemistry, etc. Literature covering the topic of epoxidation, including the catalytic aspect, is vast. No review articles have been written on the catalytic synthesis of short size, intermediate and macro-molecules to the best of our knowledge. To fill this gap, this manuscript reviews the main catalytic findings for the production of ethylene and propylene oxides, epichlorohydrin and epoxidized vegetable oil. We have selected these three epoxidized molecules because they are the most studied and produced. The following catalytic systems will be considered: homogeneous, heterogeneous and enzymatic catalysis.

International audience; Chemistry plays an essential role in our modern society [...]

International audience; The use of lignocellulosic biomass in the chemical industry can significantly contribute to respect the various international agreements on climate change. One of the most promising platform molecules issued from the lignocellulosic biomass hydrolysis is γ-valerolactone (GVL). GVL can be upgraded to valuable chemicals and produced by the hydrogenation of alkyl levulinates. Although these reactions are widely studied, seldom research focused on the solvent effect. To fill this gap, the effect of three different reaction mixtures with an excess of butyl levulinate (BL), of butanol and GVL was studied on the kinetics of BL hydrogenation to GVL over Ru/C. PC-SAFT (Perturbed-Chain Statistical Associating Fluid Theory) shows that the solubility of hydrogen is not constant during the reaction progress, and it was taken into account. To allow a fair comparison, kinetic models were developed using Bayesian statistics for each reaction mixture. The best performances were obtained when the reaction mixture has an excess of GVL.

International audience; The development of a bio-based economy has its foundations in the development of efficient processes to optimize biomass potential. In this context there are a multitude of molecules that can be either synthetized or recovered from biomass, among those the so-called 12 building-blocks reported by the US Department of Energy. Even if their identification and importance is clearly defined, research efforts concerning the purification or separation of these platform molecules are limited. To fill this gap, different configurations for the purification of levulinic acid recovered from lignocellulosic biomass are examined and compared in this work. In particular, hybrid configurations obtained by the combination of liquid-liquid extraction and distillation have been considered. It was demonstrated how a deep understanding of the subspace including all extraction-assisted simple column distillation configurations represents a fundamental step in the synthesis of different process alternatives. From a separation efficiency and economic standpoint, the proposed intensified liquid-liquid thermally equivalent configuration (LL-TE) and liquid-liquid side stream column configuration (LL-SSC) are promising solutions. Nonetheless, their performances are deeply interrelated to the purity target defined by the designer.

International audience; The use of lignocellulosic biomass as a raw material can sustain the chemical industry. There is a lack of knowledge in kinetics and thermodynamics of some of these processes, making difficult the cost analysis. For instance, the thermodynamic investigation of the hydrogenation of alkyl levulinates to γ-valerolactone (GVL) is seldom. This system is a two-step reaction comprising a hydrogenation and cyclization step. The experimental measurement of the two reaction enthalpies is challenging, and a method was developed in this manuscript. The hydrogenation of methyl levulinate (ML) and butyl levulinate (BL) in the GVL solvent was found to be an exothermic step, and the cyclization an endothermic one. The reaction enthalpy for the hydrogenation of ML in the GVL solvent, calculated to -53.25 kJ/mol, is higher than the one of BL in the GVL solvent, calculated to -38.66 kJ/mol. The reaction enthalpies for the cyclization step are similar for ML and BL system, i.e., +7.00 kJ/mol and +6.50 kJ/mol, respectively. Hence, the hydrogenation step governs the reaction temperature. A thermal risk assessment based on experiments performed under adiabatic condition was done. The thermal risk was found to be medium for this reaction system under the operating conditions used in this study.

Heterogeneous catalysts are widely used in the chemical industry. Compared with homogeneous catalysts, they can be easily separated from the reaction mixture. To design and optimize an efficient and safe chemical process one needs to calculate the energy balance, implying the need for knowledge of the catalyst&rsquo, s specific heat capacity. Such values are typically not reported in the literature, especially not the temperature dependence. To fill this gap in knowledge, the specific heat capacities of commonly utilized heterogeneous catalytic supports were measured at different temperatures in a Tian&ndash, Calvet calorimeter. The following materials were tested: activated carbon, aluminum oxide, amberlite IR120 (H-form), H-Beta-25, H-Beta-38, H-Y-60, H-ZSM-5-23, H-ZSM-5-280, silicon dioxide, titanium dioxide, and zeolite 13X. Polynomial expressions were successfully fitted to the experimental data.

Highlights • Greener and safer production of epoxidized vegetable oil. • Positive effect of semibatch operation on the reaction performance. • Kinetic modelling based on plausible mechanism for the alumina catalyzed epoxidation., Heterogeneously catalyzed epoxidation of vegetable oils by hydrogen peroxide represents a greener route for the production of epoxides and a thermally safer reaction route compared to the classical Prileschajew epoxidation approach. The epoxidation kinetics of the heterogeneous system formed by aluminium oxide catalyst, hydrogen peroxide and methyl oleate as a model compound was studied with semibatch experiments in laboratory scale. It was found that semibatch operation improved the performance significantly compared to classical batch operation, a low and constant volumetric flowrate of hydrogen peroxide increased the final oxirane yield considerably. A semibatch reactor model and a kinetic model were developed, featuring the reaction temperature, the reactant molar ratio, the catalyst loading and the mass flow rate as the most significant experimental parameters. The mathematical model was able to well describe the experimental data. The approach can be applied to other liquid–solid catalyst systems in future in order to optimize the semibatch operation policy for complex reaction systems.

International audience; Tall oil fatty acids (TOFA) are a byproduct from the Kraft pulping process, and they represent a renewable and inexpensive alternative with high potential as a renewable feedstock. Epoxidized TOFA have great potential as chemical intermediates. Epoxidation of oleic acid, TOFA, and distilled tall oil (DTO) was conducted in an isothermal batch reactor with in situ-formed peracetic acid using hydrogen peroxide as the reactant and acetic acid as the reaction carrier. Amberlite IR-120 was used as the solid heterogeneous catalyst. The catalyst loading effect, the reactant ratios, the reaction temperature (40–70 °C), and the influence of microwave irradiation on epoxidation and ring opening were studied. The application of microwave irradiation resulted in an improvement of the epoxidation rate in the absence of the catalyst. Lower product yields were obtained for the epoxidation of DTO than for TOFA because of the higher viscosity and high content of rosin acids which presumably promoted ring opening reactions. At higher temperatures, the selectivity to oxirane decayed due to ring opening. Titration analysis and NMR analysis confirmed that microwave irradiation induces the ring opening reactions for TOFA epoxidation, and it accelerates this process for DTO. The rapid nature of the microwave heating might have unchained a series of ring opening reactions between neighboring oxirane groups and with the nucleophilic agents in the reaction mixture.

International audience; The rapid progress of innovative biorefinery technologies raises the issue of emerging risk and major accident hazard in biorefineries, as process safety aspects of such technologies are not developing at the same pace with respect to their dissemination and scale-up.To address such problem, in the present work a consequence-based approach was integrated in the framework of a consolidated QRA methodology (ARAMIS), formerly developed in the context of Seveso Directive in the process industries (mainly oil&gas). Among all the possible scenarios identified using ARAMIS, Relevant Accident Scenarios (RAS) were selected by calculating hazard distances using threshold values for the evaluation of damages on human target derived from existing regulations on the control of major accident hazards.The method has been described and used to quantify the risk associated to a biorefinery process: the conversion of lignocellulosic biomass materials to levulinic acid and gamma-valerolactone, where the use of hazardous substances and severe process conditions are required.Using the proposed approach allowed to reduce the number of scenarios to be retained for further analysis. The RAS resulted 1/3 of the scenarios initially identified, simplifying the rest of the risk assessment procedure.The integrated methodology enabled to depict a risk figure for the plant analysed which is not over-conservative, being beneficial during the risk management phase, when risk reduction measures have to be selected and implemented in order to achieve risk tolerance.

International audience; Vegetable oils are renewable biomass that can substitute fossil raw materials for sustainable development. These oils are made of different types of fatty acids (building blocks), which could lead to differing reactivity toward chemical reaction. In order to investigate the correlation between reactivity and structure of vegetable oils, we have compared the reactivity of epoxidized cottonseed oil (ECSO) and its epoxidized fatty acid methyl ester (EFAME) toward carbonation reaction by using the homogeneous catalyst tetrabutylammonium bromide (TBABr). Mass transfer and physicochemical properties were determined and further applied to estimate the intrinsic rate constants during the kinetic modeling stage. It was found that densities for both systems were similar, but the difference in viscosity was important. Mass transfer coefficients were similar for the carbonated species, but the ones of EFAME and FAME were found to be ca. 100 times lower than those of ECSO and CSO. The solubility of CO2 was found to be higher in FAME derivatives than in CSO derivatives. We have found that the rate constant of carbonation of EFAME can be 1.4 times higher than the one of ECSO. A linear relationship between the carbonation rate constant of epoxidized vegetable oil and its fatty acid methyl ester with temperature was found.

The use of biomass, particularly, a second generation one, as a renewable raw material is crucial to sustain the chemical industry. To favor the development of such processes, one needs to make a cost evaluation, which requires the knowledge of process thermodynamics and kinetics. In this paper, measurements of different physicochemical properties (viscosity, density, refractive index, and specific heat capacity) were done for the systems: hydrogenation of levulinic acid or its esters to γ-valerolactone. From those physicochemical measurements, it was possible to extract the ones of the intermediates and perform a thermodynamic model assessment by using Aspen Plus. It was found that the Hysys Redlich−Kwong−Soave cubic equation of state and Benedict−Webb−Rubin−Starling virial equation of state are suitable to describe these chemical systems.

The use of calorimeter in chemical reaction engineering is a powerful tool to estimate kinetic constants. Indeed, reaction temperature is used as an online analytical signal. Nevertheless, the thermal characterization of the calorimeter must be done to avoid wrong estimation. The hydrolysis of acetic anhydride was used as a reaction model in a handmade calorimeter, because it is a fast and exothermic reaction. Several research groups have studied this reaction without taking into account the autocatalytic effect due to the production of acetic acid. To fill this gap, a kinetic model was developed by taking this phenomenon and in a thermally characterized handmade calorimeter. The estimated kinetic constants in the handmade calorimeter were found to be similar than in the established calorimeter Mettler Toledo RC1.

International audience; Epoxidized fatty acids and fatty acid esters are used as chemical intermediates and environmentally friendly bio-lubricants. The epoxidation is carried out by the Prileschajew reaction, which implies the use of hydrogen peroxide as oxidation agent and a percarboxylic acid as the oxygen carrier. The epoxidation process is slow in the two-phase system (aqueous phase and oil phase), but it can be considerably enhanced by incorporating a heterogeneous acid catalyst. The results for the epoxidation of a model compound, oleic acid were presented. A cation-exchange resin (Amberlite IR-120) was used as the heterogeneous catalyst and acetic acid was the reaction carrier. Experimental data on oleic acid epoxidation were obtained at 40–50 °C under conventional heating and microwave irradiation. The experimental set was focused on studying the catalytic effect of the solid resin. The kinetic results revealed that the presence of the heterogeneous catalyst completely masked the enhancing effect of microwave radiation. An extensive set of kinetic data obtained from a laboratory-scale loop reactor was modelled with a realistic heterogeneous model taking into account the co-existence of three phases in the chemically complex reaction system. Rate equations were presented for all the reaction steps involved: the perhydrolysis, epoxidation and ring-opening steps. The rate equations were included in the three-phase reactor model and the kinetic parameters of the system were determined by non-linear regression analysis.

The influence of inlet parameters on the production and thermal risk of complex chemical systems can be cumbersome to evaluate. To determine the optimum safe operating conditions, one needs to solve complex differential equations derived from energy and material balances. This robust approach cannot be made on-site, and it is essential to propose simplest tools to evaluate rapidly the performance and safety of some operating conditions. This is the aim of this paper that establishes explicit relationships between the production and thermal risk parameters, and the inlet parameters. In addition, it also proposes a Pareto chart that can be used to make the tradeoff between safety and performance. Such relationships and chart were developed for the production of epoxidized cottonseed oil under isoperibolic and semi-batch mode. The kinetic model developed by Zheng et (Zheng et al., 2016). was used. First, a numerical approach, i.e., least square method, was used to find explicit relationships between thermal risk parameters, production parameters and six inlet parameters. The use of such an approach allows a better understanding of this process. Second, safety and performance indicators are proposed and discussed to evaluate the operating conditions thanks to a simple and intuitive schema. Besides, this approach can be used to find the optimum conditions more rapidly.

International audience; Process safety is an important topic in the curriculum vitae of a chemical engineer. It can be a difficult course for the students and professors, because it is a frontier course between chemical engineering and safety. How to introduce this course? We think that this course should be introduced during the chemical reaction engineering, and more particularly during the mass and energy balances lectures. Thus, the students can more easily understand the concept of isoperibolic mode, secondary reactions, heat-flow rate due to chemical reactions, Semenov curves, etc. In this manuscript, we propose a pedagogical method to introduce this concept by using numerical simulation. In the first section, the roots of energy balance for the different reactors is derived. In the second section, mass and energy balances coupling is derived for the different chemical reactors. In the third section, the different thermal modes, i.e., isothermal, isoperibolic and adiabatic are described. Then, a tutorial by using a batch reactor with several exothermic reactions is treated and corrected. At this moment of the course, the instructor can introduce the last section about safety criteria by using the zero-order approximation. The rigorous mass and energy balances coupling should be introduced to the students before the current approximation made by the safety community, i.e., zero order, in process safety.

Epoxidized vegetable oils are used as chemical intermediates and biolubricants. Epoxidation of oleic acid as model compound for vegetable oils was performed in a batch-loop reactor. The system comprised a loop where the mixture was pumped through a cavity in which microwaves were irradiated. The reaction was executed by peroxyacetic acid formed in situ from acetic acid and hydrogen peroxide. An extensive kinetic study of oleic acid epoxidation in the batch-loop reactor was conducted by varying the reaction temperature (40–60 °C), the stirring and pumping speeds as well as the molar ratios of the components. Both conventional heating and microwave irradiation were used in the experiments. Epoxidation of the double bonds in oleic acid proceeded as the main reaction, while acid-catalyzed ring opening of the epoxide appeared as the side reaction. The results obtained showed that temperature, acetic acid amount and hydrogen peroxide amount accelerated both rate of epoxidation and ring opening processes. A clear enhancement of the epoxidation kinetics was accomplished with microwave heating in comparison to conventional heating, which was attributed to selective heating by the microwaves that enabled a higher interfacial mass transfer. Microwave application to epoxidation of vegetable oils is a promising process that successfully meets all the green chemistry requirements: energy saving and eco-friendly process and products.

International audience; Levulinic acid (LA) is one of the most important platform chemicals as it is a versatile building block for a variety of high value-added products, fine chemicals and pharmaceutical intermediates. Catalytic esterification of LA with alkyl alcohols leads to levulinate esters which can be used as fragrances, flavoring agents and fuel additives. In the present work, the kinetics of the levulinic acid esterification with ethanol in the presence of Amberlite IR120 was investigated in a batch reactor. The collected experimental data were interpreted with a reliable model taking into account also for the mass transfer phenomena involved in the reaction network. The kinetic model was further validated by conducting experiments in a fixed bed reactor. The reactor was characterized in terms of fluid-dynamics and the collected kinetic data were interpreted with a reliable reactor model, considering the extent of the reaction and fluid-solid mass transfer limitation.

Fossil materials are widely used raw materials in polymerization processes, hence, in many cases, the primary goal of green and sustainable technologies is to replace them with renewables. An exciting and promising technology from this aspect is the isocyanate-free polyurethane production using vegetable oil as a raw material. Functional compounds can be formed by the epoxidation of vegetable oils in three reaction steps: epoxidation, carbonation, and aminolysis. In the case of vegetable oil carbonation, the material properties vary strongly, with the composition affecting the solubility of CO2 in the reaction mixture. Many attempts have been made to model these interactions, but they generally do not account for the changes in the material properties in terms of spatial coordinates. A 2D CFD model based on the combination of the k-&epsilon, turbulence model and component mass balances considering the spatial inhomogeneities on the performance of the reactor was created. After the evaluation of the mesh independence study, the simulator was used to calculate the carbonation reaction in a transient analysis with spatial coordinate-dependent density and viscosity changes. The model parameters (height-dependent mass transfer parameters and boundary flux parameters) were identified based on one physical experiment, and a set of 15 experiments were used for model validation. With the validated model, the optimal operating temperature, pressure, and catalyst concentration was proposed.

International audience; Production of polyurethane is increasing since the recent years. Nevertheless, this production uses hazardous chemicals, which is isocyanate. Academy has put a lot of effort to develop some non-isocyanate polyurethane routes. One of the most promising is the aminolysis of cyclic-carbonate by diamine. To industrialize this way of production, kinetic and thermodynamic data are needed. The first steps were to optimize the production of methyl oleate, epoxidized methyl oleate and carbonated methyl oleate. Then, a kinetic model was built for a model reaction which is the aminolysis of carbonated methyl oleate by n-butylamine by taking into account the side reaction of amidation. The model fits correctly the experimental data. A Tian-Calvet calorimeter was used to determine the different reaction enthalpies. It was found that the reactions of aminolysis and amidation were low exothermic reactions.

A mathematical model was developed to analyze an exothermic liquid–liquid reaction system using epoxidation of oleic acid by peroxyformic acid formed in situ as an example. Kinetic and thermal parameters were included, mass transfer parameters were eliminated from the model and evaporation/condensation was taken into account. A calorimetric semi-batch reactor under isoperibolic mode was used in the experimental work. Different initial aqueous-phase concentrations of H 2 O 2 [6.5–8.8 mol/l], water [44–45 mol/l], molar flow rate of formic acid [0.02–0.54 mol/min], initial reaction temperature [50–70 °C] and amount of organic phase [34–46 wt.%] were studied. A non-linear regression method was used to estimate kinetic ( e.g. , rate constant at average temperature and activation energy) and thermal parameters ( e.g. , reaction enthalpy) of the epoxidation and ring-opening reactions. The standard reaction enthalpy changes were estimated to be −116 kJ/mol for epoxidation reaction and −50 kJ/mol for the ring opening.

International audience; The concept of linear free-energy relationships, and more particularly the Taft equation, was extended to a multiphase system with several reactions and reaction centers: the epoxidation of vegetable oils and free fatty acids. The epoxidation of vegetable oils and free fatty acids by different percarboxylic acids produced in situ is an exothermic reaction system which can lead to a thermal runaway. The safety criterion time-to-maximum-rate under adiabatic conditions (TMRad), linked to the kinetics of the system, was determined with the advanced reactive system screening tool (ARSST). We have demonstrated that TMRad values for the epoxidation of vegetable oils and free fatty acids by using different carboxylic acids follow the Taft equation. The epoxidation reaction series by different carboxylic acids was found to be more sensitive to the polar effect than steric effect. It was demonstrated that, by knowing the carboxylic acid used for the epoxidation, it is possible to predict the values of TMRad.

International audience; This paper proposes a study of different cation exchange resins, used as catalysts for the synthesis of peroxypropionic acid (PPA) from propionic acid and hydrogen peroxide at 40 °C, equimolar concentration of reactants and an apparent Brønsted concentration of 0.2 M. The catalytic activities of the resins are on the same scale as sulfuric acid at comparable concentration level and decrease in the order: Dowex 50Wx2 > Smopex-101 > Dowex 50Wx8 ≈ Amberlite IR-120 > Amberlyst 15. The influence of external and internal mass transfer limitation was evaluated. The experiments also demonstrated that a gelular resin with a degree of cross-linking equal to 8% and a particle size of more than 0.1 mm showed a stronger resistance to deactivation.

International audience; The rise in carbon dioxide (CO2) concentration in the Earth's atmosphere, and the associated strengthening of the greenhouse effect, requires the development of low carbon technologies. New carbon capture processes are being developed to remove CO2 that would otherwise. be emitted from industrial processes and fossil fuel power stations. Given the increasing importance of this technology, we report on a new educational project, which is aimed to instill greater awareness of the role of CO2 in climate change while stimulating student interest in science, technology, engineering, and the environment. The project was carried out by master students, that is, Cool(L)Cap team, who contributed to the design and manufacture of a pilot plant that demonstrates the basic operation of an amine scrubbing plant. The main goal of. the project was to develop educational material and presentations for a range of audiences, from primary school to university students and academics. In this article, we present the project team's approach to design, commission, and deliver the pilot plant and educational material as well as the feedback received from 267 students from a primary school and a university. We provide additional information to enable other educators to recreate our pilot plant design.

This paper presents a study of the epoxidation of vegetable oil in an isothermal batch reactor system equipped with microwave or conventional heating. The epoxidation reaction was performed by peroxycarboxylic acid formed in situ from carboxylic acid and hydrogen peroxide. It was demonstrated that microwave irradiation can accelerate the epoxidation velocity when the continuous phase is aqueous, which is not transparent to microwave. This tendency was observed for peroxyacetic and peroxypropionic acids.

International audience; Synthesis of peroxypropionic and peroxyacetic acids from hydrogen peroxide and their carboxylic acids was carried out in a continuous fixed-bed reactor, demonstrating the concept of green process technology: biodegradable chemicals are made with the aid of heterogeneous catalysts. This reactor was constructed with several sampling locations along its length, allowing a better kinetic investigation. A profound study of the mean residence time distribution (RTD) was performed to analyze the behavior of the flow pattern at different liquid flow rates and catalyst loadings by using step and impulse methods with different tracer molecules. It was found that impulse experiments with HCl as a tracer is the most reliable method to study the RTD, because of this tracer does not interact with the catalyst. Based on the RTD study, it was demonstrated that the temperature (in the range 30–60 °C) and the catalyst distribution inside the reactor do not affect the flow pattern, but the ratio of the catalyst mass-to-liquid ratio affects the mean residence time and the liquid dispersion. Furthermore, it was shown that the presence of an axial dispersion is negligible when the average particle diameter is

International audience; This paper describes a study of the stability of hydrogen peroxide in the presence of different aluminosilicate materials, in connection with an investigation of carboxylic acid perhydrolysis. During the reaction, aluminosilicate materials such as H-β zeolites, mesoporous material H-MCM-41 and alumina initiate the decomposition of hydrogen peroxide. The reason of the spontaneous decomposition of H2O2 is related to the partial dealumination of these zeolites. However, in the case of experiments carried out with H-ZSM-5 zeolite catalysts, a slight catalytic effect on the perhydrolysis and no spontaneous decomposition of hydrogen peroxide were noticed. The use of cation exchange resins as catalysts is more kinetically beneficial than H-ZSM-5 zeolite catalysts.

International audience; Description of the interactions between intrinsic kinetics and internal mass transfer is one of the central issues in chemical reaction engineering. A general model was developed, comprising the kinetic and mass transfer effects in porous particles reacting in batch reactors. The catalyst particle size distribution was included in the model. A numerical algorithm and software was developed to solve the model for simulation and parameter estimation purposes. The model was applied to an industrially relevant case of green chemistry: synthesis of peroxycarboxylic acids from carboxylic acids and hydrogen peroxide. Due to the potential industrial applications, the present study was focused on the acetic and propionic acid perhydrolysis. The concentrations in the bulk phase and inside the catalyst particles were predicted by the model. It turned out that the smallest ion-exchange resin particles operated under kinetic control, whereas the largest particles (higher than 300 µm ) are influenced by diffusional limitation. Thus the combined effect of reaction and diffusion along with the particle size distribution are essential ingredients in the model.

This paper describes the application of LFER to understand the mechanism of the perhydrolysis of carboxylic acids over homogeneous and heterogeneous catalysts. Several experiments were carried out with different linear carboxylic acids: formic, acetic, propionic and butyric acids; using sulfuric acid and Amberlite IR-120 as catalyst and different reaction temperatures. From the experiments, the apparent rate constants decrease in the following order: k app (PFA) > k app (PAA) > k app (PPA) > k app (PBA), in both catalytic system. Furthermore, it was found that this reaction follows Taft and Charton correlations, which implies that the steric effect of the substituent governs that reaction and the mechanism is similar between the different carboxylic acids. Comparison between homogeneous and heterogeneous catalytic system was carried out based on the analysis of the kinetic expression.

International audience; This article describes a kinetic study of the perhydrolysis of propionic acid with sulfuric acid at various molar reactant ratios (PA-H2O2 from 0.4 to 2.05), reaction temperatures (from 30 to 60 °C), and catalyst concentrations (from 0 to 1.41 M). The influence of water and acidic catalysts were taken into account to develop a suitable kinetic model. The system is nonideal, mainly due to the presence of the strong electrolyte (i.e., H2SO4), and a parameter was introduced to describe the nonideality. The kinetic and thermodynamic parameters determined by nonlinear regression analysis were statistically well identified. The standard enthalpy change of reaction was estimated to −4.17 kJ·mol-1, and the activation energy of the reaction was estimated to 44.2 kJ·mol-1.

International audience; Decomposition of peroxypropionic acid (PPA) takes place in the liquid phase, but the main products of decomposition, carbon dioxide and oxygen are transferred to gas phase. An analytical method was developed to determine the decomposition of PPA in liquid phase by means of chemical analysis of gas phase. The method is based on on-line mass spectroscopy (MS). A mathematical model for the semi-batch gas–liquid system was developed. The model comprised both kinetic and mass transfer effects. A comparison between experimental results and results predicted from the mathematical model revealed that the model can describe the essential effects of decomposition kinetics.

Nowadays, biomass and carbon dioxide valorization are considered as a helpful solution to the environmental issues of global warming and the depletion of petroleum reserves. Thus, vegetable oils have attracted increasing attention of academic and industrial communities, as one of the potential renewable biomass that can be applied to the production of fossil substitute for sustainable development, owning to their advantages of renewable, sustainable, biodegradable, and universally available with huge feedstock. Among decades of researches, epoxidation and carbonation processes are two popular application methods for vegetable oil valorization. The conversion of vegetable oils into epoxidized ones is defined by a conversion of unsaturated compound into an epoxide group. So far, the potential application for the production of epoxidized oil in the industrial is the Prileschajew oxidation, which is a wellknown conventional way to be used as the commercial production process. This type of epoxidation uses percarboxylic acid as an oxygen carrier, which is formed in situ in the aqueous phase, and then epoxidize the unsaturated groups on the vegetable oils into epoxide groups. During the process, however, this method presents side reaction of ring-opening of the epoxide group. Therefore, the selective epoxidation process conditions need to be optimized in order to minimize the ring-opening reactions. In this study, process parameters including the concentration of acid catalyst (sulfuric acid), reactants (water, epoxide group, hydrogen peroxide, acetic acid) and the reaction temperature have been discussed for the epoxidation and ring opening of vegetable oils. During the kinetic modeling stage, the related kinetic constants for the ring opening reactions were estimated. Based on this model, the ring opening by acetic and peracetic acids was found to be faster than by water and hydrogen peroxide. A semibatch reactor, where hydrogen peroxide and sulfuric acid were added, was found to be the most suitable configuration. To determine the optimum operating conditions and scale up the epoxidation or carbonation processes, it requires the database of different physicochemical properties, i.e. viscosity, density, refractive index, or specific heat capacity and the evolutions of these properties with the temperature. However, this information is absent in the literature. For this study, the evolution of these properties with temperature and compositions (double bond, epoxide and carbonated groups concentration) was determined for three vegetable oils and their corresponding epoxidized and carbonated forms (cottonseed oil, linseed oil and soybean oil). Density and refractive indices of these oils were found to vary linearly with temperature. Based on the measurement of changes in viscous stresses with shear rates, these oils were found to be Newtonian fluids. It was demonstrated that specific heat capacity follows a polynomial equation of second order with temperature. Based on these results, it was demonstrated that some correlations could be used to predict the evolutions of these physicochemical properties at different composition and temperature based on the knowledge of the property of the pure compounds..., La valorisation de la biomasse et du dioxyde de carbone est à présent considérée comme une solution aux problèmes environnementaux du réchauffement climatique et l'épuisement des réserves de pétrole. Ainsi, les huiles végétales ont attiré l'attention croissante des milieux universitaires et industriels, comme une source de biomasse potentielle renouvelable qui peut être appliquée à la production de substitut fossile pour un développement durable, due à leurs caractères renouvelables, durables, biodégradables. De plus, cette biomasse est disponible avec une énorme quantité. Durant des décennies de recherches, les processus d'époxydation et de carbonatation sont deux méthodes d'application populaires pour la valorisation des huiles végétales. La conversion des huiles végétales en huiles époxydées est définie par une conversion d'un composé insaturé en un groupe époxyde. Jusqu'ici, l'oxydation de Prileschajew est la méthode de synthèse plus efficace pour la possible industrialisation du processus d'époxydation de huiles végétales, qui est une manière conventionnelle bien connue à utiliser comme processus de production commerciale. Ce type d'époxydation utilise l'acide percarboxylique comme transporteur d'oxygène qui est formé in situ dans la phase aqueuse, et ensuite époxyde les groupes insaturés des huiles végétales en groupes époxyde. Cependant, cette méthode présente une réaction secondaire d'ouverture du cycle du groupe époxyde au cours du processus. Donc, les conditions du procédé d'époxydation doivent être optimisées afin de minimiser les réactions d'ouverture de cycle. Des paramètres de réaction, y compris la concentration en catalyseur acide (acide sulfurique), réactifs (eau, groupe époxyde, peroxyde d'hydrogène, acide acétique) et la température de réaction, ont été discutés dans cette étude pour l'époxydation et réaction d'ouverture de cycle des huiles végétales. Au cours de la modélisation cinétique, les constantes cinétiques associées pour les réactions d'ouverture du cycle ont été estimées. En se basant sur ce modèle, les réactions d'ouverture du cycle époxyde par les acides acétique et peracétique sont plus rapides que celles de l'eau et du peroxyde d'hydrogène. Un réacteur en mode semi-fermé, avec addition du peroxyde d'hydrogène et de l'acide sulfurique, est la configuration la plus appropriée pour la production d'huiles végétales époxydées. Pour déterminer les conditions optimales et passer à échelle industrielle dans les procédés d'époxydation et de la carbonation, il faut connaître différentes propriétés physicochimiques telles que la viscosité, la densité, l'indice de réfraction, la capacité thermique spécifique et les évolutions de ces données avec la température. Cependant, aucune information sur ces propriétés est disponible dans la littérature. Pour cette étude, l'évolution de ces propriétés ont été déterminées pour trois huiles végétales et leurs dérivés époxydées et carbonates (l'huile de coton, l'huile de lin et l'huile de soja) avec la température et leur composition. La densité et l'indice de réfraction ont été trouvé linéairement dépendant de la température pour les huiles étudiées. La relation entre la contrainte de cisaillement et le taux de cisaillement dans l’étude de viscosité, indique que ces huiles sont des fluides newtoniens. Il a été démontré que la capacité thermique spécifique suit une équation polynomiale du second ordre avec la température. Sur la base de ces résultats, il a été démontré que certaines corrélations pourraient être utilisées pour prédire les évolutions de ces propriétés physicochimiques à différentes compositions et températures...

Nowadays, biomass and carbon dioxide valorization are considered as a helpful solution to the environmental issues of global warming and the depletion of petroleum reserves. Thus, vegetable oils have attracted increasing attention of academic and industrial communities, as one of the potential renewable biomass that can be applied to the production of fossil substitute for sustainable development, owning to their advantages of renewable, sustainable, biodegradable, and universally available with huge feedstock. Among decades of researches, epoxidation and carbonation processes are two popular application methods for vegetable oil valorization. The conversion of vegetable oils into epoxidized ones is defined by a conversion of unsaturated compound into an epoxide group. So far, the potential application for the production of epoxidized oil in the industrial is the Prileschajew oxidation, which is a wellknown conventional way to be used as the commercial production process. This type of epoxidation uses percarboxylic acid as an oxygen carrier, which is formed in situ in the aqueous phase, and then epoxidize the unsaturated groups on the vegetable oils into epoxide groups. During the process, however, this method presents side reaction of ring-opening of the epoxide group. Therefore, the selective epoxidation process conditions need to be optimized in order to minimize the ring-opening reactions. In this study, process parameters including the concentration of acid catalyst (sulfuric acid), reactants (water, epoxide group, hydrogen peroxide, acetic acid) and the reaction temperature have been discussed for the epoxidation and ring opening of vegetable oils. During the kinetic modeling stage, the related kinetic constants for the ring opening reactions were estimated. Based on this model, the ring opening by acetic and peracetic acids was found to be faster than by water and hydrogen peroxide. A semibatch reactor, where hydrogen peroxide and sulfuric acid were added, was found to be the most suitable configuration. To determine the optimum operating conditions and scale up the epoxidation or carbonation processes, it requires the database of different physicochemical properties, i.e. viscosity, density, refractive index, or specific heat capacity and the evolutions of these properties with the temperature. However, this information is absent in the literature. For this study, the evolution of these properties with temperature and compositions (double bond, epoxide and carbonated groups concentration) was determined for three vegetable oils and their corresponding epoxidized and carbonated forms (cottonseed oil, linseed oil and soybean oil). Density and refractive indices of these oils were found to vary linearly with temperature. Based on the measurement of changes in viscous stresses with shear rates, these oils were found to be Newtonian fluids. It was demonstrated that specific heat capacity follows a polynomial equation of second order with temperature. Based on these results, it was demonstrated that some correlations could be used to predict the evolutions of these physicochemical properties at different composition and temperature based on the knowledge of the property of the pure compounds...; La valorisation de la biomasse et du dioxyde de carbone est à présent considérée comme une solution aux problèmes environnementaux du réchauffement climatique et l'épuisement des réserves de pétrole. Ainsi, les huiles végétales ont attiré l'attention croissante des milieux universitaires et industriels, comme une source de biomasse potentielle renouvelable qui peut être appliquée à la production de substitut fossile pour un développement durable, due à leurs caractères renouvelables, durables, biodégradables. De plus, cette biomasse est disponible avec une énorme quantité. Durant des décennies de recherches, les processus d'époxydation et de carbonatation sont deux méthodes d'application populaires pour la valorisation des huiles végétales. La conversion des huiles végétales en huiles époxydées est définie par une conversion d'un composé insaturé en un groupe époxyde. Jusqu'ici, l'oxydation de Prileschajew est la méthode de synthèse plus efficace pour la possible industrialisation du processus d'époxydation de huiles végétales, qui est une manière conventionnelle bien connue à utiliser comme processus de production commerciale. Ce type d'époxydation utilise l'acide percarboxylique comme transporteur d'oxygène qui est formé in situ dans la phase aqueuse, et ensuite époxyde les groupes insaturés des huiles végétales en groupes époxyde. Cependant, cette méthode présente une réaction secondaire d'ouverture du cycle du groupe époxyde au cours du processus. Donc, les conditions du procédé d'époxydation doivent être optimisées afin de minimiser les réactions d'ouverture de cycle. Des paramètres de réaction, y compris la concentration en catalyseur acide (acide sulfurique), réactifs (eau, groupe époxyde, peroxyde d'hydrogène, acide acétique) et la température de réaction, ont été discutés dans cette étude pour l'époxydation et réaction d'ouverture de cycle des huiles végétales. Au cours de la modélisation cinétique, les constantes cinétiques associées pour les réactions d'ouverture du cycle ont été estimées. En se basant sur ce modèle, les réactions d'ouverture du cycle époxyde par les acides acétique et peracétique sont plus rapides que celles de l'eau et du peroxyde d'hydrogène. Un réacteur en mode semi-fermé, avec addition du peroxyde d'hydrogène et de l'acide sulfurique, est la configuration la plus appropriée pour la production d'huiles végétales époxydées. Pour déterminer les conditions optimales et passer à échelle industrielle dans les procédés d'époxydation et de la carbonation, il faut connaître différentes propriétés physicochimiques telles que la viscosité, la densité, l'indice de réfraction, la capacité thermique spécifique et les évolutions de ces données avec la température. Cependant, aucune information sur ces propriétés est disponible dans la littérature. Pour cette étude, l'évolution de ces propriétés ont été déterminées pour trois huiles végétales et leurs dérivés époxydées et carbonates (l'huile de coton, l'huile de lin et l'huile de soja) avec la température et leur composition. La densité et l'indice de réfraction ont été trouvé linéairement dépendant de la température pour les huiles étudiées. La relation entre la contrainte de cisaillement et le taux de cisaillement dans l’étude de viscosité, indique que ces huiles sont des fluides newtoniens. Il a été démontré que la capacité thermique spécifique suit une équation polynomiale du second ordre avec la température. Sur la base de ces résultats, il a été démontré que certaines corrélations pourraient être utilisées pour prédire les évolutions de ces propriétés physicochimiques à différentes compositions et températures...