Ethylene is the first organic compound produced worldwide, with nearly 100 million tons per year
VALENCIA, 3 Abr. (EUROPA PRESS) –
The Institute of Chemical Technology – Severo Ochoa center of excellence of the Higher Council for Scientific Research (CSIC) and the Polytechnic University of Valencia (UPV) – has patented a new catalyst to purify ethylene that allows better control of the temperature range of the reaction and stops any secondary reaction, allowing the industrial process to be carried out in a safer and more efficient way. The work is published in the prestigious journal ‘Nature Catalysis’.
Purified ethylene is essential to prepare the next compounds in the chemical value chain, for example polyethylene, the second most produced plastic globally. This purification requires a catalyst, a substance that favors the process, since raw ethylene contains 1% acetylene that makes polymerization impossible and, therefore, it must be hydrogenated to ethylene.
“Currently, the catalyst to purify ethylene consists of a complicated mixture of precious metals such as palladium, which results in a poorly defined material,” explains in a statement Antonio Leyva Pérez, senior scientist at the CSIC at the ITQ who leads the study. .
For this reason, the reaction must be maintained within a very strict temperature range to avoid an unexpected increase in temperature, “since the appearance of unwanted secondary reactions would uncontrollably increase the temperature, ruining the process and causing safety problems in industrial reactors.” , points out the researcher.
The purification of ethylene is the second largest reaction in organic chemistry worldwide. Bags of all types, containers or pipes are made of polyethylene, which accounts for about 15% of the almost 400 million tons of plastics produced in 2021.
Thus, in this project they have developed a well-defined palladium catalyst, inserted in a solid metal-organic network (MOF, for Metal-Organic Frameworks), “which allows much better control of the temperature range of the reaction and stops any secondary reaction, which allows the reaction to be carried out under industrial conditions in a safer and more efficient way, avoiding the safety and cost problems associated with the current industrial process,” Leyva summarizes.
As described by the CSIC researcher, the new catalyst carries out the entire purification process on a single palladium atom linked to another single gold atom, which modifies the activity of the palladium to make it more efficient and selective and thus be able to work in a range temperatures of almost 100 degrees Celsius, compared to 50 degrees for current catalysts. Furthermore, due to the small pore size of the MOF, unwanted acetylene polymerization processes are controlled.
In his opinion, “the new catalyst could be used in industrial plants for the purification of ethylene once the scale-up of the synthesis of the material is developed.” If this material is too expensive on a kilogram scale (palladium is more expensive than gold), “there are alternatives to prepare the active center of the new catalytic material in other cheaper materials.”
The Institute of Molecular Science (ICMOL) of the University of Valencia, the University of Cádiz, the Cells-Alba synchrotron and the University of Calabria (Italy) participate in the work, published today in the prestigious journal Nature Catalysis.
The new catalyst has been patented by its inventors through a patent that describes the synthesis of the new MOF material and its excellent catalytic activity in the hydrogenation reaction of acetylene in ethylene streams. The co-ownership of this patent corresponds to both the CSIC and the UPV and the UV, in an example of collaboration between different research institutions.