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Communication Dans Un Congrès Année : 2015

KINETIC ANALYSIS AND MODELLING FOR THE NON- AND AU-CATALYSED OXIDATION OF GLYCEROL

Elzbieta Skrzynska
  • Fonction : Auteur
Mickael Capron
Franck Dumeignil

Résumé

The depletion of fossil fuels has heightened research efforts to find environmentally-friendly alternatives to petroleum-based chemicals, thereby, the production of biodiesel has increased significantly [1]. The manufacture of biodiesel lead to different co-products, among them is glycerol (GLY), which represent 10 wt.% of the final product. For this reason, the transformation of GLY in valuable chemicals (glyceric acid, glycolic acid, formic acid, etc) has gained a great interest [2]. Among the different transformation techniques, the catalytic oxidation, as a non-expensive and environmentally-friendly process, is the most developed. There are many studies which deal the kinetic analysis and modelling of the GLY oxidation. However, it is still necessary to further investigate this reaction to explain some aspects which are not clarified so far. This way, the aim of this work is to perform a kinetic modelling of the GLY oxidation. A kinetic model will be proposed by using the experimental results reported in a previous work of our groups [3] carried out in kinetic regime and a carbon balance close to 100 %. FIG1 shows the reaction pathways selected for the preliminary kinetic analysis, by analysis of experimental results reported previously [3] where C-1 (formic), C-2 (glycolic) and C-3 (glyceric) acids have been found as primary products. Direct C-C cleavage into small acids was already reported in previous studies [4]. The first kinetic model has been proposed on formal approach, by considering first-reaction order of all components. For the parameter estimation, non-linear regression was performed by using Matlab. Finally, a statistical analysis of the estimated parameters was performed by the calculation of the standard deviations and the correlation matrix. Obtained rate constants at different reaction temperatures are listed in FIG2, along with a comparison of the calculated and experimental concentrations for the Au-catalysed reaction at 100 °C. Results revealed that the Au catalyst was active and selective towards formic and tartronic acids, and the activation energies obtained were similar than those reported elsewhere [5]. In general, the concentrations predicted with the kinetic model fitted adequately with the experimental ones. However, statistical analysis results (not shown) revealed a strong correlation between different rate constants. Therefore, the model will be improved by the incorporation of further parameters that could influence the activity of the process, such as the base concentration, the reaction orders and in the case of the Au-catalysed reactions, the adsorption constants of the GLY and the obtained products. Moreover, the reaction mechanism will be further analysed by additional experiments of competitive reactions.
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Dates et versions

hal-01150705 , version 1 (11-05-2015)

Identifiants

  • HAL Id : hal-01150705 , version 1

Citer

N. Diaz, Elzbieta Skrzynska, Mickael Capron, Franck Dumeignil, P. Fongarland. KINETIC ANALYSIS AND MODELLING FOR THE NON- AND AU-CATALYSED OXIDATION OF GLYCEROL. 3rd International Symposium on Green Chemistry, May 2015, La Rochelle, France. ⟨hal-01150705⟩
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