Eco-friendly method to make chemicals developed

Chinese scientists have developed a new, eco-friendly method for carbonylation — a century-old chemical reaction essential for manufacturing everyday products like medicines, food preservatives and cosmetics.

The breakthrough, published in the journal Nature on Oct 21, offers a cleaner, cheaper and more efficient way to transform basic chemicals into high-value products without relying on costly precious metals or producing acidic wastewater.

Carbonylation is a fundamental process in the modern chemical industry. It works by attaching carbon monoxide to hydrocarbons — compounds made of hydrogen and carbon — to create building blocks for bulk and fine chemicals, including acetic acid, plasticizers and fragrances.

In the new study, a research team led by Liu Zhongmin, an academician at the Chinese Academy of Engineering and director of the Dalian Institute of Chemical Physics under the Chinese Academy of Sciences, used zeolites as standalone catalysts to drive the reaction.

Zeolites are solid crystalline materials packed with microscopic, uniform pores and channels. Acting like tiny sieves, they selectively allow certain molecules to pass through while blocking others based on their size and shape.

Building on two decades of research into zeolite catalysis — which previously enabled large-scale ethanol production without precious metals — the team spent nearly three years exploring whether zeolites could catalyze a wider range of carbonylation reactions.

They successfully established two new reaction routes using zeolites and water to produce widely used chemical compounds. By reacting water with propylene, a basic hydrocarbon gas, the team produced isobutyric acid, a key ingredient in cosmetics. Through a similar process using ethylene, another common hydrocarbon gas, they generated propionic acid, a widely used food preservative.

The researchers discovered that the tight space inside the zeolite pores acts like a protective cage. It encourages the desired chemical reaction while physically preventing molecules from clustering together to form unwanted byproducts, a process known as polymerization.

Furthermore, because zeolites are solid, they can be easily separated from liquid products. This avoids the complex separation steps and toxic liquid waste common in conventional liquid phase manufacturing.

The team also found that changing the shape and size of the zeolite pores acts as a "molecular switch", directing different raw materials into specific chemical outcomes. This shifts catalyst design away from traditional trial-and-error metal testing toward predictable, tailor-made catalyst engineering.

"The modern chemical industry is already mature, leaving very little room to discover entirely new reactions," Liu said. "Yet, by using zeolites, our team found that olefins — a class of unsaturated hydrocarbons — can react directly with carbon monoxide and water to produce acids. This pathway is fundamentally different from the conventional method of obtaining acids through oxidation."

Liu emphasized that the process is broadly applicable, noting that in principle, any olefin can undergo carbonylation using this route.

By replacing expensive metal catalysts with solid zeolite structures, the innovation lays the groundwork for greener, lower-energy chemical manufacturing. Liu added that the team will selectively advance the technology toward industrial application.

limenghan@chinadaily.com.cn