RUDN University Chemists Improve Ethanol Conversion Using Activated Carbon Based Supports

RUDN University chemists have improved the catalyst for ethanol conversion. With it, a mixture of compounds with a high octane number was obtained. This was achieved thanks to a special substrate for the activated carbon catalyst. In the future, such developments will help to obtain more environmentally friendly fuel additives and thus reduce the carbon footprint. The results are published in Fuel.

Ethanol is used as a raw material for the production of acetaldehyde, diethyl ether, chloroform, ethylene and other compounds. Now that there is more and more talk about the depletion of oil resources, ethanol has another important meaning. It can itself serve as a biofuel , and become the basis for the production of higher alcohols and oxygenates – organic additives to conventional fuels. The conversion of ethanol to more useful compounds is called ethanol conversion. Special catalysts are used for it. Recently, molybdenum-based catalysts have become popular. RUDN University chemists have improved one of these catalysts. 

“As climate change and the depletion of oil resources become more and more significant, it is important to explore alternative energy sources and resources for the chemical industry. In recent years, attention has shifted to the production of ethanol-based fuels, as well as conversion using various catalytic systems,” said Dipheko Tshepo, post-graduate student at RUDN University. 

The chemists took a catalyst consisting of molybdenum, cobalt, potassium and sulfur (KCoMoS2). Such catalysts are usually enhanced with a scaffold support. RUDN University chemists compared several substrates. One consisted of alumina – aluminum oxide. The second substrate was also made of alumina, but additionally coated with carbon. Two more substrates consisted entirely of activated carbon.

The action of the catalyst on different substrates was tested using the example of the reaction of the conversion of ethanol to higher alcohols in the presence of hydrogen and helium. RUDN University chemists conducted a series of experiments, changing the parameters. The best conversion, i.e., the proportion of the gas that entered into the reaction, was provided by a substrate made of activated carbon of the commercial grade AG-3 – about 60%. Helium turned out to be the best medium for conversion. The octane number – an indicator of fuel quality – for the products obtained turned out to be more than 113. For ordinary ethanol, it is 105. 

“The resulting mixture of oxygenates contains mainly ethyl acetate and derivatives of higher alcohols. They are widely used as high performance solvents in the paint industry. In addition, they are valuable high-octane motor gasoline components with good miscibility and a reduced carbon footprint,” said Dipheko Tshepo, post-graduate student at RUDN University.