A new method for joining molecules can significantly reduce chemical production waste and its negative impact on the environment

(Nanowerk News) Chemical production accounts for 40% of all energy currently used in manufacturing, and the process also generates toxic waste solvents that pollute the environment and pose health risks to humans and animals. A study recently published in the journal Science (“Diels-Alder reaction acceleration with mechanical distortion”) details a new mechanochemical method that has the ability to manufacture chemicals without such deleterious effects.

Researchers with the Nanoscience Initiative at the Advanced Science Research Center at the CUNY Graduate Center (CUNY ASRC), University of Pennsylvania, and University of California-Merced took a unique approach that advances opportunities to use mechanochemicals in large-scale production. This technique uses organic chemistry and nanotechnology to bond molecules together and make chemicals without using expensive solvents that pollute the environment. The research team’s findings have major implications for various manufacturing sectors, including the production of pharmaceuticals and materials for various medical and industrial uses. The tip arrangement transfers the dienophile molecule (red) to the anthracene-modified surface (green). Upon contact, the ends form a nanoreactor, where pressure is applied which accelerates the Diels-Alder cycloaddition reaction. For their study, the authors took a monolayer of molecules placed on a silicon wafer and pushed reactive molecules into it using an array of ends, which created a new chemical. The experimental setup allows researchers to precisely control the intermolecular forces, leading to a new understanding of what happens in these reactions. (Image: Yerzhan Zholdassov)

“This is a very exciting breakthrough, because this discovery makes mechanochemistry a reliable way of producing chemicals, and allows us to do it without the harmful byproducts and huge energy requirements of current manufacturing techniques,” said the study’s lead author Adam Braunschweig, a professor of Chemistry and Biochemistry with the CUNY ASRC Nanoscience Initiative and Hunter College’s Department of Chemistry.

“When we push molecules, we find that they twist into new, more reactive forms that require less energy to combine and produce the desired chemical,” said first author Yerzhan Zholdassov, a doctoral student at the Braunschweig Lab.

The experiments allowed researchers to measure the amount of force required to make chemical reactions predictable and reliable and demonstrated that mechanochemistry is a viable and scalable technique for manufacturing chemicals in a more sustainable and cost-effective manner. The new techniques can also be used to create new drugs and materials that cannot be made using current solvent-dependent techniques.

Co-author Robert Carpick, a professor in the University of Pennsylvania’s Department of Mechanical Engineering and Applied Mechanics who collaborated on the project, added: “This discovery would not have been possible without chemists working closely with mechanical engineers in a truly cross-disciplinary way. Chemists are essential for designing and conducting experiments, but we must combine their advanced knowledge of chemistry with advanced analytical mechanics to understand – through experimentation and theory – how mechanical forces accelerate chemical reactions here. Teamwork makes the difference.”