Search

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.

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

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

The focus on the green manufacturing production is becoming more and more important in France. Le Havre is a city located in the north-western France, which concentrates more than a third of French refining capacity. However, simultaneously, the pollution caused by industries needs to be controlled. Furthermore, Le Havre would like to be the first city that does really ecological industrial park in France. Industrial symbiosis is a key concept of industrial ecology, which studies the physical flows of materials and energy in the local industrial systems. There are few studies that support the assumption of economic and environmental benefits of industrial symbiosis. So, in order to have a WIN-TO-WIN situation, we proposed a mathematical optimization control model. The model will help the manufacturing industries to reduce related costs, and the negative environmental impact would be decreased simultaneously. Best to our knowledge, currently, it does not exist any other general mathematical optimization model for constructing and optimizing an eco-industrial park.

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.

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; In the chemical industry, a key step for the assessment of thermal risk and runaway is the identification of autocatalytic reactions. In this field, many estimation methods based on dynamic differential scanning calorimetry (DSC) measurements have been developed. As a rule, a screening of the most hazardous chemicals is conducted. In the first step, the measured heat release curve from dynamic DSC gives the apparent activation energy level. In the second step, the characteristic behaviour of a possible autocatalytic decomposition is pointed out with an isothermal DSC measurement. Unfortunately, when an endothermic process precedes the exothermic decomposition, identification is rather difficult or even impossible. A new method based on microwave dielectric measurements of chemicals has been developed. This method consists of a preliminary recording of the initial reactants and final product dielectric properties. Then the normalized extent of a chemical process is determined from the behaviour of its complex permittivity. As an illustration, the thermal decomposition of a well known curing agent, 2,2’-azobis-isobutyronitrile is studied.

A rotating film pertraction of phenol from its dilute aqueous solutions and copper from ammoniacal dilute leach solutions are presented. Mathematical models are developed to describe the batch pertraction processes. Using experimental results and models, the partial mass transfer coefficients and the kinetic constants were evaluated.

International audience; A hybrid estimation method is proposed to estimate simultaneously the kinetic and energetic parameters of chemical models. This method combines a genetic algorithm with a local convergence method, the former generating initialisation points for the latter. The method is applied to a real complex chemical system : the saponification of ethyl acetate at a concentration of 1 mol.L-1. The reaction is carried out in a calorimetric reactor which determines experimental profiles of power delivered or absorbed by the reaction mass. A model, based on mass and energy balances in the reaction mass, including the kinetic and energetic parameters of the reaction, allows to calculate the power profile. The comparison between the experimental and calculated profiles gives the criterion to minimise. The parameters of the model are successfully determined. The hybrid method determines more efficiently and more rapidly the solution of the problem than a set of several estimations with a local convergence method.

Equipment faults in industrial chemical reactors lead to variations in product quality. Due to the highly energetic potential of the reaction mass, they can in addition cause runaways or major incidents. The methodology for detecting process anomalies in a chemical reactor, is based on a parametric estimation-prediction of the reaction mixture. The recursive least square method with forgetting factor has been retained to appreciate the evolution of parameters in real time. Thus allowing us, to point out a criterion of decision based on relative prediction error between two successive vector parameters. In this paper, we consider only the stirred jacketed chemical reactor which is largely use in pharmaceutical fine chemistry. Two incidents linked to the hydrodynamic cited by Etchelles (Etchelles., 1994) as main causes of reported incidents are studied: a change in the fluid flow regime in the jacket and the immediate stop of the agitator. In each case, a dynamic simulation model, based on energetic balances, is established to represent the most accurate reactor thermal behaviour.