You’re likely touching something right now that had its roots in propylene oxide.
The compound is used to produce plastics, and thanks to University researchers, its production may be revolutionized.
A paper published in the March 29 issue of Science Magazine reveals that the addition of copper and intense light — nearly 140 times more intense than an average sunny day — provides a more environmentally friendly way to bond propylene and oxygen.
Suljo Linic, an Engineering associate professor, who led the research, said the substance that could catalyze propylene oxide would be the “holy grail” of the chemical engineering discipline because the highly versatile compound has an intricate synthesis. Engineering graduate student Andiappan Marimuthu and University alum Jianwen Zhang also authored the article.
“It’s a gateway chemical, and, ideally, you would just be able to use it by just combining propylene and oxygen,” Linic said.
Currently, producing propylene oxide requires or yields hazardous compounds, such as chlorine or isobutane. Linic said copper can be used in the process of catalyzing propylene and oxygen if in its pure metallic form. However, when oxygen bonds with copper on the surface of the copper nanoparticle, it negates its catalytic abilities.
Though copper remains metallic in the core, the reaction between the substances occurs at the surface of copper, so its core is insignificant. The addition of a light source, though, retains copper’s catalytic function.
Linic said light removes oxygen and reduces the copper oxide coating on copper nanoparticles, revealing the metallic copper core. This core allows the catalysis of propylene oxide.
“As you shine light, the electrons from copper start hopping into an anti-bonding state,” Linic said. “The oxygen just starts breaking bonds with copper.”
While Linic and his team have discovered a way to halt oxidation, he said it’s unreasonable that this technique could be used to reverse the effects of rusting on an old nail.
“I would never use this to prevent rusting,” Linic said. “This happens at 200 degrees Celsius; it happens in presence of propylene. It’s not just as simple as shining light.”
Additionally, the compound’s commercial possibilities remain uncertain. Fifty percent of the propylene and oxygen in the reaction using light combined to form propylene oxide. Though this is an improvement from the 20-percent yield rate of a light-free reaction, Linic said the commercial sector would likely prefer a rate above 80 percent.
Commercialization of the compound would also entail designing a special reactor to ensure the light reaches each particle of copper. However, Linic said the research’s bottom line was its development of a theory.
“The most important thing here is that you can shine light and change the outcome of a reaction fundamentally.”
—Follow Rachel Premack on Twitter at @rr_premack.