2
RUDN University chemists created cheap catalysts for ethanol conversion

RUDN University chemists created cheap catalysts for ethanol conversion

RUDN University chemists proposed a new way to synthesize catalysts for the conversion of ethyl alcohol. The obtained materials are promising catalysts for the selective conversion of ethanol, which is an important stage in the development of an alternative technology for obtaining valuable chemical synthesis products based on plant raw materials.

Ethanol fuel is ethyl alcohol, it is produced from plant material by fermentation of industrial or agricultural waste biomass. It is used as a more environmentally friendly fuel compared to gasoline. But this is not its sole use, ethanol can be converted into acetaldehyde, diethyl ether and other chemicals that are in demand in the industry. Highly efficient catalysts are required to trigger such chemical reactions. However, existing catalysts contain precious metals, and therefore they are too expensive to use. RUDN University chemists proposed new catalysts based on aluminium and zirconium, modified with copper.

"The best-known catalysts for ethanol conversion are based on oxides promoted by noble metals. However, they are quite expensive. A more affordable option is catalysts with copper as the active phase, but so far, the best option has not been found among them. Improvements are required to use these catalysts to ensure both high conversion and selectivity of the reaction -- that is, to leave as little ethanol as possible unprocessed and at the same time to obtain the necessary substances, and not by-products", Anna Zhukova, associated professor, PhD, from the Department of Physical and Colloidal Chemistry of RUDN University.

RUDN chemists combined two approaches to improve the efficiency of catalysts for acetaldehyde synthesis. First, they combined oxides of several metals in nanocomposites: aluminium, cerium, and zirconium. The researchers synthesized five types of powders with different oxides ratios. Five of them was prepared at a relatively low temperature of 180°C, and another five was heated to 950°C. This made it possible to form different structures in the materials. The calcined samples had a large diameter and pore volume.

The second idea was to add copper. All the powders were soaked in an aqueous solution of copper nitrate, dried at room temperature, and exposed to a flow of hydrogen at 400°C. After that, the finished catalysts were tested in the ethanol vapor dehydrogenation reaction. Chemists placed them in a thin layer on a porous filter, and then fed alcohol vapors in the helium flow. The reaction was carried out at temperatures from 240°C to 360°C.

All nanocomposites showed catalytic activity, but the conversion and selectivity indicators were different. At the same temperature, but with different catalysts, the yield of acetaldehyde was from 32 to 95%, and the proportion of recycled ethanol was from 17 to 57%. Most of the target product was obtained using catalysts with 5% aluminum oxide in the composition.

"All obtained systems demonstrated ? high alcohol conversion and selectivity to acetaldehyde. The copper containing catalysts with 5% aluminium oxide produced significant amounts of acetaldehyde with selectivity above 80 % at 3600C. We found that the mixed composition of the oxides creates conditions for the formation of active centres on the surface of the catalyst from copper ions with different charges. The best option is to use a mixture of oxides with a small content of aluminium in the synthesis of the catalyst and calcinate them at 950°C", Anna Zhukova from RUDN University.

The results of the study are published in Catalysis Today.

Article in Indicator

Visiting Professors View all
03 Nov 2017
Michele Pagano is a graduate of the University of Pisa, a leading scientist, the author of more than 200 publications in international journals, and a participant in many international research projects
2575
International scientific cooperation View all
03 Nov 2017
The main goal of the RUDN University and UNISDR Office for Northeast Asia and Global Education and Training Institute for Disaster Risk Reduction at Incheon (UNISDR ONEA-GETI) cooperation is to obtain knowledge about disaster risk reduction and international experience in this area for creating training courses for basic and additional professional education in RUDN
1390
Similar newsletter View all
07 Jul
RUDN University Biologist: salted water saves fish from stress when transporting

RUDN University biologist with colleagues from Brazil and Iran found how to alleviate the stress of fish during transportation. It turned out that this can be achieved with salted water.

63
20 Apr
RUDN University agronomists increased wheat yield by 65%

RUDN University agronomists have proposed a new scheme for fertilizing winter wheat, which allows increasing the yield by 68%. The key to this is in the combination of nitrogen and growth regulators.

125
20 Apr
RUDN Biologists Study Live Microorganisms in Toxic Liquids for Metalworking

RUDN biologists have studied microorganisms that can survive in metalworking fluids. The results will allow “picking up” bacteria and fungi that can process toxic waste fluids into a harmless product.

119
Similar newsletter View all