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The synthesis of functionalized polymyrcene, from bio-based myrcene and from carbon dioxide, is performed, thanks to the unique features of microflow systems.

Limitations regarding process design, optimization, and control often occur when using particular process simulators. With the implementation of connection methodologies, integrated tools could be made by coupling popular process simulation software with each other or with programming environments. In the current paper, we summarized and categorized the existing research regarding the application of multi-software engineering in the chemical industry, with an emphasis on software connections. CAPE-OPEN, COM, OPC, and native integration were discussed in detail, with the intention to serve as a guide for choosing the most suitable software combination and connection. These hybrid systems can handle complex user-defined problems and can be used for decision support, performing custom unit operations, operator training, process optimization, building control systems, and developing digital twins. In this work, we proposed the use of process simulator Aspen HYSYS linked together with the numeric computing platform MATLAB to solve a reaction kinetic parameter identification problem regarding the production of γ-valerolactone.

γ-valerolactone can be a game-changer in the chemical industry because it could substitute fossil feedstocks in different fields. Its production is from the hydrogenation of levulinic acid or alkyl levulinates and can present some risk of thermal runaway. To the best of our knowledge, no studies evaluate the thermal stability of this production in a continuous reactor. We simulated the thermal behavior of the hydrogenation of butyl levulinate over Ru/C in a continuous stirred-tank reactor and performed a sensitivity analysis. The kinetic and thermodynamic constants from Wang et al.’s articles were used. We found that the risk of thermal stability is low for this chemical system.

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.

The solvent is of prime importance in biomass conversion as it influences dissolution, reaction kinetics, catalyst activity and thermodynamic equilibrium of the reaction system. So far, activity-based models were developed to predict kinetics and equilibria, but the influence of the catalyst on kinetics has not been succesfully predicted by thermodynamic models. In this work, the thermodynamic model ePC-SAFT advanced was used to predict the activities of the reactants and of the catalyst at various conditions (temperature, reactant concentrations, γ-valerolactone GVL cosolvent addition, catalyst concentration) for the homogeneously acid-catalyzed esterification of levulinic acid (LA) with ethanol. Different kinetic models were applied, and it was found that the catalyst influence on kinetics could be predicted correctly by simultaneously solving the dissociation equilibrium of H

The aim of this project is to find an appropriate mode for green sustainable manufacturing and production. Thus, the concept of this model encourages the development of synergy and leverage of resource networks in order to reduce waste and pollution, and to share resource efficiently. To the best of our knowledge, there is currently no other general mathematical model for designing and optimizing exchange material/energy flows in an industrial park. The purpose of this work is to propose a relative advanced dynamic multi-objective model. Simulations have been performed by using the NIMBUS (Nondifferentiable Interactive Multi-objective Bundle-based optimization System) method. This model can assure a win-win situation for industries and environment.

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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A rigorous mathematical model was developed for a complex liquid–liquid–solid system in a batch reactor. The approach is general but well applicable for the indirect epoxidation of vegetable oils according to the concept of Nikolaj Prileschajew, implying in situ prepared percarboxylic acids as epoxidation agents. The model considers intra- and interfacial mass transfer effects coupled to reaction kinetics. The liquid phases were described with chemical approach (aqueous phase) and a reaction–diffusion approach (oil phase). The oil droplets were treated as rigid spheres, in which the overall reaction rate is influenced by chemical reactions and molecular diffusion. The model was tested with a generic example, where two reactions proceeded simultaneously in the aqueous and oil phases. The example (i.e., fatty acid epoxidation) illustrated the power of real multiphase model in epoxidation processes. The proposed modeling concept can be used for optimization purposes for applications, which comprise a complex water–oil–solid catalyst system.

International audience

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.

International audience

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.

A rigorous mathematical model was developed for a complex liquid-liquid-solid system in a batch reactor. The approach is general but particularly well applicable for the indirect epoxidation of vegetable oils according to the concept of N. Prileschajew. The model considers intra- and interfacial mass transfer effects coupled to the reaction kinetics. The liquid phases were described with chemical approach (aqueous phase) and a reaction-diffusion approach (oil phase). The oil droplets were treated as rigid spheres, in which the overall reaction rate is influenced by chemical reactions and molecular diffusion phenomena. The model was tested with a generic example, where two reactions proceeded simultaneously in the aqueous and oil phases. The example (i.e. fatty acid epoxidation à la Prileschajew) illustrated the power of the real multiphase model in epoxidation processes. The proposed modelling concept can be used for optimization purposes for many applications, which comprise a complex water-oil-solid catalyst system.

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.

Substitution of fossil feedstock by vegetable oils is growing due to environmental constraints and oil depletion. Among the different valorization routes for vegetable oils, epoxidation of their unsaturation is widely used. The epoxidation is an exothermic reaction which could lead to a thermal runaway. There are different routes for the vegetable oil epoxidation: Prileschajew by performic and peracetic acid, which are the most used. Another promising alternative is the direct epoxidation by hydrogen peroxide by alumina. The goal of this manuscript is to rank the thermal risk of these three epoxidation routes by determining the safety parameter time to maximum rate under adiabatic condition. The Advanced Reactive System Screening Tool was used to conduct these experiments. It was found that the direct epoxidation is safer than the two other routes.

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 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.

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.

Polyurethane polymer is more and more famous because of its versatile properties. The current production process requires the use of isocyanate, which is a hazardous chemical. An alternative eco-friendly route of production is the aminolysis reaction between a cyclic-carbonate, from carbonated vegetable oil, and a diamine. Nevertheless, the kinetics of this reaction system is slow, which might be due to steric hindrance. In order to predict and evaluate this steric hindrance, different amines were tested for the aminolysis of carbonated methyl oleate. Four amines were used: n-butylamine, methylbutylamine, ethylbutylamine and dibutylamine. Kinetic models for the aminolysis with each amine were developed. A relationship between structure and reactivity of each substituent was found through the concept of Linear Free Energy Relationships.

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.