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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.

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.

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During the operation of chemical reactors, a failure in the cooling system can lead the reactor to operate under the risk of thermal runaway. The present work proposes a study of failure detection, using the divergence criterion and the Thomas and Bowes criterion. In order to evaluate the detection performance, two exothermic reactions with different kinetics were chosen, and the results show that Thomas and Bowes criterion detects earlier the failures than the divergence criterion. However, Thomas and Bowes may present false alarm about the risk of thermal runaway.

Deep eutectic solvents (DES) are an interesting alternative to conventional amines. Due to their biodegradability, lower toxicity and lower prices, DES are considered “more benign” sorbents for CO2 capture than ionic liquids. To study the effect of water on the properties of choline chloride (ChCl)/glycerol mixtures (1:3 on a molar basis), the density and viscosity of ChCl/Gly with different water content (30%, 40% and 50%) were measured at temperature from 293.15 K to 333.15 K at atmospheric pressure, the CO2 solubility in (ChCl/Gly) with water was determined from 293.15 K to 373.15 K and at pressure from 0.5 MPa to 3 MPa. The result shows the dramatically influence of water in the viscosity but not in the CO2 solubility and Absorption.

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.

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.

Since the early 1990s, considerable efforts have been made in researching and applying approaches for faults detection and diagnosis in chemical processes. The occurrence of chemical accidental events due to thermal runaways has serious consequences for the human, environmental and economic and encourage these efforts. This is the main motivation for this paper that details a fault detection and diagnosis approach for exothermic reactions. The proposed approach is based on the temperature measurements. It compares the collected measurements with a reference behavior for early thermal runaway detection. Once a fault is detected, characteristic features are extracted from the successive measurements collected within a time window. The fault isolation is based on a classification of these features with respect to several faulty modes. The studied faults are the most responsible for thermal runaway events. A multiset of linear classifiers and binary decision diagrams indexed with respect to the time are used for that purpose. The synthesis of peroxyformic acid in a batch reactor is considered to validate the proposed method by numerical simulations and experiments. The performance of the proposed method is carried out in a systematic way in order to evaluate its robustness and efficiency.

Organic carbonates have attracted considerable attention because of their numerous applications. The direct association of CO2 and alcohol to synthesise these carbonates is one of the most promising routes, when considering the economic and the environmental aspects. A significant number of researchers have worked on the catalysis and the dehydration of these reactions, but very few have dealt with the study of the thermodynamic equilibrium and the kinetics of these reactions. The objective of this work is to study the synthesis of diethyl carbonate (DEC) and propylene carbonate (PC). A parametric study was conducted by varying the temperature, the pressure and the initial concentration. Equilibrium constants were determined experimentally and compared to available published data. Kinetic models are developed based on four mechanisms, two of which are the mechanisms of Langmuir–Hinshelwood and Eley–Rideal. Mean deviations between the experimental data and the modelling were below 10% for all the mechanisms. The best fit was obtained for the mechanism of Langmuir–Hinshelwood for the synthesis of DEC and PC. Activation energies of 100 kJ/mol and 77 kJ/mol were determined for the synthesis of DEC and PC, respectively.

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.

Vegetable oils are more and more used in industry for the production of biodiesel, biolubricant, or polymer. In this context, production of polyurethane by nonisocyanate routes involves the production of epoxidized and carbonated vegetable oils. The determination of the optimum operating conditions and the scale-up of these processes require the knowledge of different physicochemical properties such as viscosity, density, refractive index, or specific heat capacity. These data are rare for the epoxidized and carbonated vegetable oils, and the evolution of these data with the temperature is absent in the literature. This article proposes to study the evolution of these properties with temperature and composition in double bond, epoxide, and carbonated groups. It was demonstrated that density and refractive index of these oils vary linearly with temperature. Viscosity of these oils, which were found to be Newtonian fluids, is an exponential function of temperature. The ratio of specific heat capacity at a t...

Phosphoric acid, a non-renewable chemical, is used in different industries. Production of this chemical from natural phosphate can be done by two routes: wet process and thermal process. The nature of the natural phosphate, i.e., its chemical composition, plays an important role in the kinetics and thermodynamics of phosphoric acid production. Thus, the establishment of a kinetic model, based on reaction mechanism, for the dissolution of natural phosphate is cumbersome due to the presence of impurities. Besides, one should use an online analytical method because the dissolution reaction is fast. The dissolution of two natural phosphates with different percentages of phosphorus pentoxide (P2O5), phosphate samples (28 mass% of P2O5) from Gafsa region (Tunisia) and phosphate samples (18 mass% of P2O5) from Cheketma-Kasserine region (Tunisia), was studied from a kinetic and thermal aspect. Experiments were performed by using a Tian—Calvet calorimeter. Two acid solutions were used for the dissolution: one with phosphoric acid (S1) and the other a mixture of phosphoric and sulfuric acid (S2). For both natural phosphates, it was found that in case of using S1 solution the heat released due to the dissolution was lower than in case of using solution S2. This difference was explained by the precipitation of monohydrate sulfate calcium to its dihydrate form. By using a granulometry distribution lower than 500 μm, heat released during the dissolution of both phosphates by S1 was similar, i.e., − 230 J g−1, and the same observation was done by using S2 solution, i.e., between − 300 and − 350 J g−1. We have demonstrated that granulometry distribution plays an important role, and by using a granulometry lower than 120 μm for Cheketma-Kasserine region phosphate, the heat released during the dissolution was higher, i.e., − 400 J g−1 with solution S2. Avrami model was found to describe the precipitation of calcium sulfate, and three distinguished domains were obtained by using Gafsa region phosphate compared to two domains with Cheketma-Kasserine region phosphate.

The influence of gas/liquid mass transfer on the valorisation reaction of CO2 with epoxides using epichlorohydrin in a stirred batch reactor was investigated in this study. The rate of absorption of CO2 into the liquid was studied in a dynamic way between 50 and 90 °C and at different stirring speeds (100–500 rpm). Two different systems were observed: (i) CO2/epichlorohydrin and (ii) CO2/epichlorohydrin/catalyst, in order to compare and determine the mass transfer coefficient and the enhancement of the absorption when the latter takes place in the presence of a catalyst. The results suggest that the valorisation reaction followed a slow reaction regime in which the reaction did not occur in the mass transfer film but instead took place within the liquid bulk. Therefore, the reaction rate seemed to control the overall process, but according to the specific reaction regime found, both the liquid holdup and the interfacial area should be enhanced to increase the rate of the reaction and the efficiency of the process. Under the conditions studied in this work, the mass transfer coefficient of the liquid phase (kLa) was found to be in the range of 1.0 × 10−3 to 1.0 × 10−2 s−1 and the enhancement factor (E) was between 0.4 and 0.9.

For more than 100 years, mercury and arsenic have been used for the preservation of natural history collections. This may represent a risk for staff as they may be exposed to these substances by inhalation, by skin contact or by unintentional ingestion of settled dust. In this work, we present results from a monitoring of lead, mercury and arsenic in the air and settled dust at the Natural History Museum of Rouen (Normandy, France). Relatively high levels of arsenic were measured in the air, with concentrations occasionally over the recommended value of 2 μg m−3 for a working atmosphere (NIOSH REL). Analysis of settled dust has shown a significant contamination with arsenic, lead and mercury compared to house dust respectively with median values of 58, 5507, 11 mg kg−1. Finally, Hg(0) concentrations were measured with highest values in the herbarium storage area (150–200 ng m−3) with a peak value of up to 1100 ng m−3 when manipulating herbarium sheets. Generally, the exposure of staff to these toxic substances appeared to be quite limited when compared for instance, with dietary intake. However, the concentration of arsenic in the air leads to an excess lifetime cancer risk by inhalation estimated to be 5.26 10−4, which requires special consideration.

International audience; Cheap and readily available 2-aminopyridine and related compounds can be used as organocatalysts for the conversion of epoxides into cyclic carbonates. This reaction gives high conversions under solvent-free conditions and is amenable to a kilogram-scale conversion under mild conditions.

Capture, storage and valorisation of CO2 are efficient solutions to reduce the emissions of greenhouse gas. To improve these technologies, there is a need to have a good knowledge of the interactions between CO2 and some current solvents. In this article, the solubility of CO2 in methanol, ethanol and 1,2-propanediol is measured by a constant-volume method for temperatures between 283.15 K and 373.15 K and for pressures below 6.0 MPa. The same method is used for glycerol for pressures up to 2.0 MPa. For all of the studied solvents, the solubility increases when temperature decreases and when pressure increases. No literature data was available for this wide range of temperature for ethanol, methanol, 1,2-propanediol and glycerol. Henry’s law constants are calculated for each temperature and are compared between to one another. The solubility of CO2 in these solvents increases in the following order: glycerol

A new and original high pressure reactor has been designed and developed for continuous flow chemistry under microwaves at industrial scale. The reactor originality is that the microwave applicator is the reactor itself. It allows then the use of metallic and thick walls for the reactor adapted to a use at high pressures and high temperatures. Wave propagation coupled to heat transfer was simulated using COMSOL Multiphysics® and the design was optimized in order to minimize wave reflections and maximize energy transfers in the reacting medium. This leads to extremely good energy yields. Experiments confirm that the microwave energy is fully absorbed by the reacting medium. The reactor allows continuous chemical reactions at a kg/h scale, under microwave heating, up to 7 MPa and 200°C. The double dehydration of hexylene glycol has been performed under various operating conditions demonstrating then the operability of this new reactor. This article is protected by copyright. All rights reserved.

This work is focused on the synthesis of organic carbonates from CO2 and ethanol. A parametric study of the synthesis of diethyl carbonate from ethanol is performed in a 100 mL batch reactor. The influence of pressure and temperature is studied and we prove that the presence of water strongly decreases the yield in diethyl carbonate as an equilibrium is quickly reached. One method to improve this yield is to remove water from the reaction mixture to shift the equilibrium toward the formation of carbonates. The chemical methods give good results but separation and regeneration associated steps are prohibitive. For these reasons, a physical technique like pervaporation is chosen to remove water. The study of a pervaporation cell with membrane PERVAP 4100 gives good results for the dehydration of ethanol alone even at low concentrations of water from 0.33 %wt to 0.15 %wt. Twelve experiments on the dehydration of a mixture of ethanol, diethyl carbonate and water are performed. The calculated separation factors show a very good selectivity for water. That means that even in the presence of diethyl carbonate, the membrane has still a selective water permeability.

Over the past decades, serious industrial events affecting lives, facilities and environment have occurred in chemical industry. Among the most critical events are the phenomena of thermal runaway that often lead to important damages. The rapid detection of thermal runaway events and the isolation of the most probable cause are major challenges to ensure safe operations. The objective of this work is to propose a method for early detection of faults in a chemical reactor based on a reference model and for isolating the fault cause. The reaction of perhydrolysis of formic acid to peroxyformic acid by hydrogen peroxide is used as a test case. The kinetic model of the reaction was computed in order to simulate the reaction in normal and abnormal modes. In a first stage, the method was validated by simulation data and an experimental validation is now in progress. As a consequence, the proposed method can contribute to the safety of chemical reactors in the chemical industry.

Accidental events in chemical industry can cause damages to human health, environment and economy. To prevent such events in industries, it is essential to identify and analyze the past events. To the best of our knowledge, such an analysis has not been done for the French chemical industry sector, which is the second producer in Europe. To fill this gap, 169 events were selected and collected in the French database ARIA (Analysis, Research and Information on Accidents). These events occurred between 1974 and 2014. The causes and consequences of the events were analyzed. The study shows that the causes were mainly related to operator errors. Then, a semi-quantitative analysis of risk was also carried out, based on the frequencies and consequences of the events. This analysis confirms that chemical industry activities present a significant risk. Based on this analysis, national agencies can make some recommendations or rules in order to reduce the number of events in chemical industry.

International audience; This paper brings to the fore the key parameters set out on thermal yield and energy efficiency in microwave industrial processes, specifically, in the transient phases. It examines in detail two industrial operations: thermoset polymer curing and flow chemistry under pressure. Overall tuning systems are necessary for energy optimisation, but on the other hand, vessels, pipes, moulds and conveyor belts made of lossy materials are required for holding products or carrying materials. The impact of these inserts on the temperature profile of the heated product and on energy (the power usage and energy efficiency), were experimentally and theoretically examined. It was demonstrated that these parameters have to be considered for process design and calculations. Looking at these two examples, one can see how transient phases are crucial for the required power of the microwave generator and the process design.

International audience; This article presents and discusses the results of a dielectric properties measurement intercomparison on a ceramic material, in the microwave frequency region from 500 MHz to 20 GHz and at variable temperatures from 20 °C to 250 °C. The same ceramic samples have rigorously been tested using three different techniques: a reflection method using a coaxial probe coupled to a network analyzer and two types of resonant cavities techniques (cylindrical and rectangular). This study highlights the advantages and drawbacks of each technique and demonstrates that the real part ε’r and the imaginary part ε”r of the permittivity can be advantageously and separately determined by using different shapes and volumes of samples. In addition to dielectric properties, valuable informations about the surface state of the material can also be obtained. Finally, it is shown that combining the different methods can be a benefic and a clever way to obtain very accurate results in a wide range of temperature or frequencies.

The thermal safety of chemical processes requires knowledge of the safety parameters that quantify the probability, such as time to maximum rate under adiabatic conditions (TMRad), and the severity, such as adiabatic temperature rise under adiabatic conditions (ΔTad). The zero-order approximation is used to ease the determination of TMRad values at different process temperatures; but how can one be sure that this approximation is acceptable, compared to the use of an intrinsic kinetic model? In the literature, there are no such studies that compare the values of TMRad by using zero-order and intrinsic kinetic models. For that, decomposition of hydrogen peroxide in the presence (and in the absence) of copper sulfate was studied in an advanced reactive system screening tool (ARSST) unit. This calorimeter operates under near-adiabatic conditions, based on heat loss compensation principle, and by using a background heating rate (β). In a first stage, a kinetic model was built to estimate the intrinsic kinetic...

CO2 capture is still a major challenge for the environment and decarbonization of gas streams. It has been industrially feasible for several decades using chemical absorption by alkanolamine solvents. The purpose of this work is to characterize the mass transfer in a spray contactor during CO2 absorption using monoethanolamine as a solvent. A new, effective way to investigate mass transfer is to measure the refractive index during the reactive absorption. Indeed, the concentration and temperature evolution inside the droplet during absorption induces a modification of the refractive index. By using rainbow refractometry technique (GRT), the liquid side mass transfer coefficient was measured in a controlled gas atmosphere during a transfer process in aqueous 30 % (w/w) monoethanolamine and compared to the literature.

An efficient Co-ZSM-11 catalyst has been synthesized for benzaldehyde production by the selective styrene oxidation. Reaction parameters such as catalyst mass, reaction temperature, molar ratio styrene/hydrogen peroxide and stirring speed were optimized, by performing the styrene oxidation reaction in a stirred batch system with fine particles of Co-ZSM-11 in suspension under microwave heating. A kinetic study was done by using the initial rate method and the Arrhenius parameters were estimated. This catalyst presents a higher reaction rate about 30% with respect of those found in literature and a higher selectivity towards benzaldehyde about 80% at optimal conditions. Fil: Azzolina Jury, Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigación y Tecnología Química. Universidad Tecnológica Nacional. Facultad Regional Córdoba. Centro de Investigación y Tecnología Química; Argentina. Laboratoire de Sécurité des Procédés Chimiques. Rouen; Francia Fil: Polaert, Isabelle. Laboratoire de Sécurité des Procédés Chimiques. Rouen; Francia Fil: Pierella, Liliana Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigación y Tecnología Química. Universidad Tecnológica Nacional. Facultad Regional Córdoba. Centro de Investigación y Tecnología Química; Argentina Fil: Estel, Lionel. Laboratoire de Sécurité des Procédés Chimiques. Rouen; Francia

International audience; Experimental study of carbon dioxide (CO2) capture from waste incinerator flue gas is presented. A specific pilot plant has been achieved based on absorption/desorption process using MonoEthanolAmine (MEA) solvent. Several experiments have been carried out at laboratory and industrial site. The pilot is fully instrumented to establish precise balances. Laboratory experiments allow to measure overall mass transfer coefficient KGaw for several pilot operating conditions. Long laboratory and industrial runs provide an estimation of MEA chemical resistance against waste incinerator flue gas. The experiments also allowed the analysis of NO2 and SO2 absorption through the solvent as well as the accumulation of Heat Stable Salts (HSS) for a full scale CO2 capture unit fed by a waste incinerator flue gas.

This work measures oxygen concentration in the system MEA/H2O/CO2. A polarographic probe and the Winkler’s method have been used in this study. The influence of several parameters have been studied: MEA concentration in the range 100 w = 0 to 80, CO2 loading in the range 0 to 0.5, and temperature from 10 °C up to 60 °C. Measurements have been carried out at atmospheric pressure. We show that oxygen concentration decreases as temperature drops, but also as CO2 loading increases. MEA concentration does not affect oxygen solubility.

International audience; This article presents the different microwave continuous reactors existing, which are reported in literature to carry out chemical synthesis with a more efficient way. It shows how the methods and tools of chemical engineering can be useful and necessary to define, characterize and optimize the microwave reactors. This review scans continuous microwave reactors, by describing the different types of microwave technologies used (multimode, single-mode, coaxial or guided transmission …). It then focuses on the various existing reactor geometries and on the control of the electromagnetic field homogeneity. The problem of temperature measurement and overall instrumentation is also addressed (input power, reflected power, continuous adaptation …). This review scans the most efficient microwave continuous flow reactors existing in the literature and highlights how the microwave technology is used as well as chemical engineering tools. It points out the reactors geometries, the control of the electromagnetic field and the measurement of the physical parameters (Temperature, microwave power, etc.). Finally, the scale-up of continuous-flow microwave reactors is examined through the existing lab-scale and semi industrial pilot plants described in literature.

Doped zeolites with transition metals were prepared for their application to the synthesis of chemical compounds under microwave irradiation. The zeolite crystalline structures were verified by XRD. Their surface areas were determined by the BET method. Lewis and Brönsted acid sites were quantified by FTIR of adsorbed pyridine in zeolites. The characterization of acidic properties revealed the generation of new Lewis acid sites after transition metal incorporation into zeolites. The dielectric properties of compacted zeolites were measured by using a reflection method. The temperature profiles of these compacted beds were measured during heating under microwave irradiation. Heating phenomena in zeolites were interpreted using a modified Debye model. Two main dielectric mechanisms were determined in zeolites: rotational polarization phenomenon and interfacial polarization. The selective catalytic oxidation of styrene with hydrogen peroxide was studied over zeolites doped with transition metals in a batch system, under conventional and microwave heating. Benzaldehyde was the main product in all the samples under study. Styrene conversion showed an important influence of the transition metal nature and content and so, the kind of zeolite structure used. With the present experimental conditions, no difference was proved between microwave and conventional heating neither on activity nor on selectivity. Fil: Azzolina Jury, Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigación y Tecnología Química. Universidad Tecnológica Nacional. Facultad Regional Córdoba. Centro de Investigación y Tecnología Química; Argentina. Institut National des Sciences Appliquées; Francia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Polaert, Isabelle. Institut National des Sciences Appliquées; Francia Fil: Estel, Lionel. Institut National des Sciences Appliquées; Francia Fil: Pierella, Liliana Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigación y Tecnología Química. Universidad Tecnológica Nacional. Facultad Regional Córdoba. Centro de Investigación y Tecnología Química; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Thermal safety assessment for multiple exothermic reaction systems in multiphase reactors is challenging. One of the first step is to determine the presence or absence of secondary reactions producing non-condensable gaseous products. Then, a kinetic and thermal study should be performed to evaluate the value of the heat-flow rates due to chemical reactions. Epoxidation of a free fatty acid by a percarboxylic acid produced in-situ was studied. A classical approach by determining the adiabatic temperature rise (ΔTad) and the time to maximum rate under adiabatic conditions (TMRad) by microcalorimetry was used. Then, different cooling and stirring failure scenarii in a semi-batch lab-scale reactor under isoperibolic mode were performed. It was confirmed that the formation of peroxyformic acid governs the overall reaction kinetics and the reaction temperature. It was confirmed that in case of cooling failure, mechanical agitation should be maintained.

Cet article fait le point sur la mise en œuvre du chauffage par micro-ondes pour la synthese organique. L’approche developpee ici balaie plusieurs aspects : elle apporte les connaissances indispensables sur la thermique micro-onde, la technologie des systemes micro-ondes et les capteurs associes, liste les avantages et les limites au travers d’exemples de reactions organiques et propose des preconisations. Le sujet est aborde avec une vision combinee chimie et genie des procedes.

Biomass valorization processes are being used more frequently in industry. These processes are greener because they use some renewable and biodegradable raw materials, but are they safer? We propose to study the thermal stability of different epoxidized and carbonated vegetable oils. The severity of the thermal risk, i.e., adiabatic temperature rise, was determined by using differential scanning calorimetry tools. The probability of the thermal risk, i.e., time-to-maximum rate under adiabatic conditions, was determined by using an accelerating rate calorimeter. By analyzing these safety criteria, we have found that the thermal risk, essentially during storage and reactor loading, can be assumed to be negligible.

International audience; The absorption of carbon dioxide into monoethanolamine (MEA) solution has been studied. A specific setup allowingcontrolling gas-liquid interface has been studied. It is based on a stirred reactor. This study presents the determinationof physicochemical and kinetic parameters. Determination has been done for MEA solution with and withoutsulphuric acid. This acid will illustrate the accumulation of SOx present in the fumes of a typical industrial process.