Influence of Catalyst Acid/Base Properties in Acrolein Production by Oxidative Coupling of Ethanol and Methanol

Significance Statement

Acrolein is the simplest form of unsaturated aldehyde and is widely used in the chemical industry as an intermediate for the synthesis of a number of chemicals including methionine, acrylic acid, biocides, fragrances and many more. In the past, Acrolein was produced industrially by aldolization of formaldehyde and acetaldehyde. Later, a preparation method based on propylene oxidation was adopted and widely researched. Recently, reference to bulging interest in more diverse raw materials and the necessity to curtail greenhouse emissions, and the need to optimize the supply of raw reactants, a new production process beginning with renewable feedstock such as ethanol, glycerol, and methanol have been considered.
Glycerol dehydration has been adopted as an alternative for the production of Acrolein. This comes with several benefits because glycerol is an ubiquitous co-product of the oleochemical industry as well as biodiesel production. Glycerol dehydration also comes with some drawbacks. Glycerol as a coproduct of oleochemicals and biodiesel is normally available in the ratio of about 10 wt% of oil used. This implies that for a large biodiesel plant of 250kt/year, only 25kt of glycerol will be produced, which will subsequently be turned into 10kt/year Acrolein assuming 70 mol% yield. This fits well the demand for fine chemicals, but not the large markets of the commodity chemicals.
For this reason, there remains the need to come up with alternative processes to synthesize Acrolein or acrylic acid cheaply, implementing a route that will eventually use renewable resources. A team of researchers under the guidance of Aline Auroux from the University of Lyon (IRCELYON) in France and Jean-Luc Dubois at Arkema, prepared a series of catalysts by impregnating a silica support with oxide precursors to undertake the direct oxidative coupling of methanol and ethanol, involving alcohols oxidation to aldehydes and cross-condensation of acetaldehyde and formaldehyde to generate Acrolein. The addition of the basic oxides of group I and II of the periodic table to the silica support allowed for the modulation of basicity and acidity on the surface of the catalyst. Their research work is published in ChemSusChem and was identified as a very important paper.
The research team decoupled the reaction in two steps; oxidation and the aldolization, by applying two consecutive reactors in a bid to evaluate the role of acid-base attributes of silica-supported oxide catalysts. They performed the oxidation of a blend of ethanol and methanol to acetaldehyde and formaldehyde over a FeMoOx catalyst. The product was then transferred to a subsequent reactor without intermediate separation. This is where aldol condensation as well as dehydration to Acrolein was done over supported oxides. The researchers then investigated the effects of the acid-base attributes on the selectivity towards Acrolein under oxidizing conditions.
Characterization of the catalysts exhibited unique physicochemical attributes that can be referenced to their catalytic performance for the Acrolein synthesis under oxidizing conditions. In a bid to improve selectivity to Acrolein, the authors needed to decrease carbon dioxide production by enhancing the acidity of the aldolization catalysts. The balance between acidity and basicity enhanced the selectivity of Acrolein. For this reason, fine-tuning the acid-base surface attributes was important for improving the Acrolein selectivity and to curtail carbon dioxide production referenced to over-oxidation.
The authors observed that the magnesium oxide supported on silicon dioxide catalyst was the most active for Acrolein production under oxidizing conditions due to the presence of acidic and basic sites. Acrolein production was observed to diminish when the acidic sites were poisoned by ammonia flow implying that their presence was necessary for the Acrolein yield. Acrolein, ethanol, acetaldehyde, methanol carbon dioxide and carbon monoxide were the main quantified products detected in both catalysts tests. Their study concluded although catalysts synthesized offered promising yields of Acrolein, further research and development is required to make for a feasible process.

About the author

Dr. AUROUX, Aline
IRCELYON-CNRS, 2 Avenue Einstein, 69626 Villeurbanne, France
[email protected]
Tel: 33-472445398 (office)    33-614105858 (mobile)


Aline Auroux is currently Director of research Emeritus at the Institut de Recherches sur la Catalyse et l’Environnement de Lyon ( IRCELYON, UMR 5256 CNRS-UCBLyon1), an academic laboratory belonging to the Centre National de la Recherche Scientifique (CNRS) of France. After a PhD in Thermodynamics and Inorganic Chemistry, she has spent most of her career in the fields of catalysis and adsorption microcalorimetry. Her main areas of research concern the determination of surface properties of solid catalysts, such as the adsorption properties or the acid-base or redox character of catalytic sites.
She has performed numerous adsorption and reaction kinetics studies involving gas-solid or liquid-solid systems using calorimeters linked to other techniques such as volumetry, gas chromatography, thermogravimetry, mass spectrometry, UV-vis…, and has established scales of acidity/basicity in number and strength for numerous oxide and zeolite catalysts. She is also involved in the study of catalytic systems for hydrogen production and storage, air and water depollution, and renewable energies.She headed a group entitled “Clean and renewable energies” from 2006 to 2013. She has published more than 330 articles in international journals (H-index=50. Citations=9869), 17 book chapters and one book.  She is currently vice-president of the French Chemical Society (SCF).

About the author


Jean-Luc DUBOIS is Scientific Director at Arkema. He is in charge of Corporate R&D linked with Catalysis, Processes, Renewables and Recycling. He supervises the long-term projects in this area, and builds the relationships with academic partners and companies for collaborative research.

Graduated from the Hautes Etudes Industrielles (HEI), he did a Voluntary Service Overseas in Saudi Arabia at the KFUPM/RI. He obtained is PhD from the Institut Français du Pétrole (French Institute of Petroleum) for his work on Catalysts for Oxidative Coupling of Methane. After a Post-Doctorate at the National Chemical Laboratory for Industry (Tsukuba, Japan), he found a Research Scientist position at the R&D Centre of the refining company elf-antar-france (now TOTAL), and stayed 2 years in the laboratories of Japan Energy in a collaborative research project on Hydrodesulphurization catalysts. He moved to the chemical division of the group, elf-atochem (now in-part Arkema) in 1997, and successively stayed in the R&D Centres in Saint-Avold and Pierre-Bénite (France), where he worked on oxidation catalysts and started several research projects including dehydration of glycerol to acrolein/acrylic acid, oxidative coupling of alcohols, cross metathesis to monomers for polyamide, hydroformylation for monomers, reactive castor seed crushing to methyl-ester and detoxified seed meal.

He is the author of more than 100 publications and 150 patent applications.


Aleksandra Lilic, Simona Bennici, Jean-Francois Devaux, Jean-Luc Dubois, and Aline Auroux. Influence of Catalyst Acid/Base Properties in Acrolein Production by Oxidative Coupling of Ethanol and Methanol. ChemSusChem 2017, 10, 1916 – 1930.  


Go To ChemSusChem 


Further reading

Lilić A, Wei T, Bennici S, Devaux JF, Dubois JL, Auroux A. A Comparative Study of Basic, Amphoteric, and Acidic Catalysts in the Oxidative Coupling of Methanol and Ethanol for Acrolein Production. ChemSusChem. 2017 Sep 11;10(17):3459-3472.

Go To ChemSusChem 

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