Acrolein production by oxidative coupling of a mixture of biosourced alcohols over spinel catalysts: influence of magnesium substitution by transition metals

Autor: Folliard, V., Postole, G., L., MARRA, J.-l., Dubois, Auroux, A.
Přispěvatelé: IRCELYON-Approches thermodynamiques, analytiques et réactionnelles intégrées (ATARI), Institut de recherches sur la catalyse et l'environnement de Lyon (IRCELYON), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), IRCELYON, ProductionsScientifiques
Jazyk: angličtina
Rok vydání: 2021
Předmět:
Zdroj: XLII National Conference on Calorimetry, Thermal Analysis and Applied Thermodynamics
XLII National Conference on Calorimetry, Thermal Analysis and Applied Thermodynamics, Jan 2021, Udine, Italy
Popis: SSCI-VIDE+ATARI+VFO:GPO:AAU; National audience; Acrolein is the simplest unsaturated aldehyde widely used in the chemical industry. Thanks to the conjugation of vinyl with a carbonyl group, acrolein possesses a high degree of reactivity which makes it a very good intermediate for numerous syntheses such as acrylic acid, methionine, or biocides. Nowadays, the major way of synthesis of acrolein is by propylene oxidation. However, considering the need of reducing greenhouse gas emission and finding more environmentally friendly methods of production, new processes have been developed to produce sustainable acrolein from renewable resources [1-2]. In this respect, oxidative coupling of biobased alcohols is becoming aninteresting alternative method to replace fossil-fuel based propylene production. By oxidative coupling of alcohols, acrolein is produced in a two-step process, the first stage concerns the oxidation of methanol and ethanol to formaldehyde and acetaldehyde respectively on a redox (FeMoOx) catalyst. It is followed, in a second stage, by the aldolization and dehydration of the mixture of aldehydes on an acid/base catalyst to obtain acrolein.Aldolization reactions are known to be driven by acid/base properties. Then, enhanced yield and selectivity towards acrolein should be obtained by improving the cross-aldolization reaction on tuned acid/base catalysts [3-4]The aim of the present study is to produce acrolein in a single reactor from alcohols (methanol/ethanol) thanks to the development of catalysts with a good balance between acidic and basic sites. To increase selectivity in acrolein without formation of too much COx, spinel catalysts where magnesium was partly or totally substituted by transitionmetals, supplied by Baikowski, were investigated. The acidic and basic properties of the catalysts were determined by adsorption microcalorimetry of NH3and SO2probe molecules, respectively. The experiments were performed at 150 °C in a Tian-Calvet heat flow calorimeter (C80 from Setaram, Lyon) linked to a volumetric line equipped with a Barocel capacitance manometer for pressure measurements. This apparatus allows to obtain the number, strength, and strength distribution of the active sites. Besides, to study the affinity of catalysts for the reactants, adsorption microcalorimetry of formaldehyde and acetaldehyde has been done following the same protocol as for NH3and SO2 but at a lower temperature (80°C). Then, catalytic reaction was performed in oxidative conditions to study how the basic and acidic properties can influence the catalytic activity. Among spinel catalysts, the best results were displayed by (0.8Mg ; 0.2Mn) Al2O4with 31 % yield at 285°C (GHSV 5000 h-1) directly followed by (0.8Mg ; 0.5Mn)Al2O4 with 30% acrolein yield.It appears that acrolein production seems to be depending on the cationic species, increasing with ionic radius. Successive adsorptions of acetaldehyde and formaldehyde using adsorption microcalorimetry were performed to further investigate the mechanism of adsorption. Results are shown in Fig 1.These experiments evidenced the isolation of acetaldehyde by formaldehyde at the surface of the catalyst thus explaining the absence of crotonaldehyde (which is the product of self-aldolization of acetaldehyde) and the predominance of acrolein in the final products [5].
Databáze: OpenAIRE
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