Researchers from University of Chicago developed a new method to break certain carbon-to-carbon bonds to create chemicals from plants
Majority of chemicals that are found naturally or created synthetically contain carbon-on-carbon bond as the primary structure. These bonds are modified during processes to create new useful molecules. However, a particular subset of these bonds is very stable and challenging to break open. New approaches to cut and rearrange such bonds is a key to find valuable new chemicals or more efficient or greener methods to create these chemicals. Lignin is a molecule found in plants and trees and is considered as an alternate source of the chemicals made from crude oil that are utilized to produce plastics and fertilizers. However, lignin is composed of several tough carbon-carbon bonds.
Now, a team of researchers from University of Chicago devised a new method to split certain carbon-carbon bonds to create chemicals from plants. According to Guangbin Dong, professor of chemistry at UChicago and coauthor of the study, an efficient approach to cleave carbon-carbon bonds can facilitate maximum use of lignin as a sustainable alternative to petroleum. However, these carbon-carbon bonds are often connected with particularly strong non-polar links. Subjecting these bonds into certain configurations that enable a close interaction with a metal catalyst can lead to splitting of bonds. However, no catalyst was known to break such unstrained, non-polar bonds in lignin.
The researchers developed a new method to use a metal hydride catalyst to break the bonds. The metal hydride functions as an active intermediate and enters into the carbon bonds and later sticks to hydrogen molecules. According to the researchers, although the approach is not suitable for commercial use, it offers proof of concept for further research in the near future. “This provides an opening for further study of such methods,” said Dong. “Fundamentally, we want to know the limits of what kind of carbon-carbon bonds could be activated.” The research was published in the journal Nature Chemistry on November 05, 2018.