Biofuel by-product can be recycled using gold catalyst

Scientists are developing gold catalysts to recycle one of the main by-products of biofuel production, glycerol. The chemical products obtained from the process are valuable to medicine, agriculture, the cosmetics industry and other sectors.

Published in the journal Current Organic Synthesis, the study was completed by scientists from the University of Milano, the National Autonomous University of Mexico, Tomsk Polytechnic University, the Institute of Catalysis and Petrochemistry of Mardrid and the University of Porto.

"Today the production of biofuels is an important area in many countries. They can be obtained from a great variety of biomasses. In Latin America, sources include orange and tangerine peel as well as banana skin. In the US, biofuels are produced from corn; in the central part of Russia and Europe, sources are derived from rape (Brassica napus). When processing these plants into biofuels, a large amount of glycerol is formed. Its esters constitute the basis of oils and fats. Glycerol is widely used in the cosmetics industry as an individual product.” Alexey Pestryakov from Tomsk Polytechnic University told Phys.org.

“However, much more glycerol is obtained in the production of biofuels – many thousands of tons a year. As a result, unused glycerol merely becomes waste. Now, a lot of research groups are engaged in this issue as to how to transform excess glycerol into other useful products. Along with our foreign colleagues, we offered catalysts based on gold nanoparticles."

Using gold as a catalyst is one of the most effective techniques for obtaining useful products such as aldehydes, carboxylic acids and esters from glycerol. However, the metal’s high reactivity means it can only really be used on a nanolevel, according to Phys.org.

"In a piece of gold, there will be no chemical reaction. In order to make gold become chemically active, the size of the particles should be less than two nanometers. At that scale, it has amazing properties," says the scientist.

"A great challenge in this area is that gold catalysts are very rapidly deactivated, not only during work, but even during storage. Our objective is to ensure their longer shelf life. It is also important to use oxygen as an oxidizer, since toxic and corrosive peroxide compounds are often used for such purposes," said Alexey Petryakov.