Carbon dioxide (CO2), the primary greenhouse gas emitted primarily through the burning of fossil fuels, is one of the primary causes of climate change. Using CO2 directly from impure sources could be beneficial for the green economy.
A team of researchers led by an Oregon State University has developed a novel compound that allowed them to harvest carbon dioxide from smokestacks and use it to create commercially valuable chemicals. The new metal-organic framework, loaded with a common industrial chemical, propylene oxide, can catalyze the production of cyclic carbonates while scrubbing CO2 from factory flue gases.
This is important as cyclic carbonates are a class of compounds that is receiving growing interest both at the academic and industrial levels. The cyclic carbonates can be prepared using the greenhouse gas carbon dioxide as a building block. This odorless, colorless, and biodegradable liquid can be utilized as an aprotic polar solvent.
The new findings reveal that useful products such as battery electrolytes and pharmaceutical precursors can be derived from the same process that is deployed to clean emissions from manufacturing facilities, bolstering green-economy initiatives.
Researchers developed the new, three-dimensional, lanthanide-based metal-organic framework (MOF). The lanthanides are a group of soft, silvery-white metals whose applications range from night vision goggles to flints for cigarette lighters. The MOF can also be used to catalyze cyclic carbonate production from biogas, which is a mix of carbon dioxide, methane, and other gases arising from the decomposition of organic matter.
“We’ve taken a big step toward solving a crucial challenge associated with the hoped-for circular carbon economy by developing an effective catalyst,” said chemistry researcher Kyriakos Stylianou of the OSU College of Science, who led the study. “A key to that is understanding the molecular interactions between the active sites in MOFs with potentially reactive molecules.”
A MOF is an inorganic-organic hybrid, a crystalline porous material made up of positively charged metal ions surrounded by organic “linker” molecules, in this case, lanthanide metals and tetracarboxylate linkers. The lanthanide MOFs are also selective for carbon dioxide, meaning they’re not bothered by the presence of the other gases contained by industrial emissions and biogas.
Cyclic carbonates have a broad range of industrial applications, including polar solvents, precursors for polycarbonate materials such as eyeglass lenses and digital discs, electrolytes in lithium batteries, and precursors for pharmaceuticals.
“These are very exciting findings,” Stylianou said. “And being able to directly use carbon dioxide from impure sources saves the cost and energy of separating it before it can be used to make cyclic carbonates, which will be a boon for the green economy.”