"Palladium" is a rare and expensive metal, of which Russia is the main global producer, followed by South Africa (Reuters)
The chemical industries - including the pharmaceutical industry - rely on a process called "catalysis", which is based on the use of a substance known as a "catalyst" to facilitate the process of a chemical reaction by reducing the activation energy required for it to occur, which makes it proceed more quickly.
The main materials used in this task are rare metals, most notably the expensive “palladium”, of which Russia is the main producer globally, followed by South Africa, where the former produced about 88 metric tons of it in 2022 (a metric ton is equivalent to 1,000 kg), while the latter’s production reached 80 metric tons, and its average price at that time reached 2178 US dollars per ounce.
Heterogeneously fabricating nickel carbide nanoparticles is the important breakthrough made by the Japanese team (Getty)
Due to the fear that any geopolitical disturbances would cause a global disruption to its supply chain, research teams around the world are working to provide a local alternative that is more abundant and cheaper.
A Japanese study published in the European Chemistry Journal claims to have found a suitable alternative, which is “heterogeneous nanoparticles of nickel carbide,” and this alternative has been tested in the production of nylon and plastic.
The critical step in nylon production
The production of nylon and some types of plastic includes multiple steps:
First:
Choosing the appropriate raw materials. The main components include diamines (organic compounds containing two amine groups), dicarboxylic acids or their derivatives.
Second:
Polymerization of these raw materials to form a polymer chain (polyamide polymer).
Third:
“Formation of nitrile precursors” by incorporating nitrile compounds (one of the organic compounds) into the polymer structure.
Fourth:
Hydrogenation of nitrile to primary amines (one of the organic compounds) using a palladium catalyst.
Fifth:
The primary amines obtained from the hydrogenation step undergo additional reactions and processing to obtain the final product of nylon or plastic.
Sixth:
Forming the resulting polymer into the final product through various manufacturing techniques, such as extrusion, spinning, or molding.
The fourth step, which is catalyzed by the imported “palladium metal,” is crucial in production, and what a Japanese research team from Osaka University did was to prepare a local chemical catalyst alternative to palladium, using a common metal, nickel carbide.
Hydrogenation of nitriles to primary amines is carried out by a palladium catalyst (Reuters)
How did the Japanese overcome the problems of cheap catalysts?
The Japanese research team was not the first to think of using nickel carbide, but they formed it in a heterogeneous nanostructure, bypassing the problems that usually arise when using such cheap catalysts.
Many cheap metal catalysts require difficult experimental conditions, such as high pressures and temperatures, to carry out the chemical transformation mentioned in the fourth step (converting nitriles to primary amines). Previous studies that produced nickel carbide catalysts in the form of simple nanoparticles did not succeed in overcoming these problems. However, The “heterogeneous” method of preparing nickel carbide nanoparticles was successful.
Sho Yamaguchi, a professor in the Department of Materials Engineering Sciences at the Graduate School of Engineering Sciences at Osaka University, said in a press release issued by the university, “The heterogeneous catalyst, when compared to simple nickel nanoparticle catalysts, showed four times greater activity, even though it works in... Under mild reaction conditions (1 bar of hydrogen pressure and a relatively low temperature of about 150 °C), the catalyst was reusable (at least three times), and reaction yields were high (up to 99%).”
Structural nickel is a microcrystalline porous nickel catalyst used in chemical processes for the hydrogenation or hydrogen reduction of organic compounds (Shutterstock)
3 reasons for excellence...and 3 questions waiting to be answered
Thus, the Japanese team's significant breakthrough appears to be the heterogeneous fabrication of nickel carbide nanoparticles for use in catalysis.
Khaled Abdel Hay, professor of materials engineering at Assiut University (southern Egypt), in a telephone interview with Al Jazeera Net, attributes the effectiveness of this heterogeneous shape to several reasons, which are:
First: Surface reactivity:
Heterogeneous nanoparticles usually have a higher surface area and more active surface sites due to their complex structure, and this can enhance their catalytic activity in various chemical reactions.
Second: Catalytic selectivity:
Heterogeneous catalysts can exhibit enhanced selectivity in catalytic reactions, as the specific arrangement of active sites on their surfaces can facilitate specific reaction pathways.
Third: Reusability:
Heterogeneous catalysts are often designed for easy separation from the reaction mixture, making them more easily recovered and reused in multiple cycles.
Illustration of the new catalyst design (European Chemistry Journal)
However, Abdel-Hay points out - despite his praise for what was achieved in the study - that its results are still in the laboratory range, explaining that there are three questions that need to be addressed in subsequent studies so that it can be recognized that nickel carbide nanoparticles in a heterogeneous form have become a suitable alternative to metal. Palladium on the applied scale, these questions are:
First:
Can the method reported in the study be scaled up to fabricate heterogeneous nickel carbide nanoparticles for industrial applications, and what challenges might arise in large-scale production?
Second:
In addition to the selective hydrogenation of nitrile, what other chemical transformations and reactions can the catalyst facilitate?
Third:
How does the use of nickel carbide nanoparticles align with sustainability goals in the chemical industry, and what are the environmental impacts and benefits associated with this catalyst compared to other catalytic systems?
A step forward
For their part, the Japanese did not exaggerate in their assessment of the breakthrough achieved in the study, and stressed that further steps are required.
“This work is an important step forward in increasing the sustainability of a class of chemical reactions required to manufacture medicines and many other everyday products,” Tomo Mizugaki, a professor in the Department of Materials Engineering Science at Osaka University’s Graduate School of Engineering Sciences and a co-author of the study, said in the press release. "Nickel catalyst is much cheaper than the noble metal, and because the experimental procedures required are simple, the possible applications for further chemical transformations should be straightforward, and that is what we will be working on."
He adds: "We are excited that our research will help reduce the use of expensive metals, and furthermore our theoretical calculations provide insights that will help us improve the catalyst for additional applications."
Source: Al Jazeera + agencies