Carbon dioxide from exhaust fumes used to make new chemicals
To stop global warming, governments are advocating reducing the amount of greenhouse gas put into the atmosphere. But some argue that such action won’t be enough, we will need to remove CO2 already present. Reduction of CO2 is a big challenge and requires large amounts of renewable energy.
Until then, short-term solutions to remove CO₂ from fossil fuel power plants is becoming necessary, including carbon capture and storage (CCS). The other option is to use the storage part, as new research from Korea shows, and to use CO₂ directly from exhaust gases to make new chemicals.
Carbon capture involves the “capture” of CO2, either by a chemical or physical process. Often CO2 from a exhaust gas stream is captured by nitrogen containing compounds called amines. The reaction results in the formation of solid chemicals. These can be heated, allowing the CO2 to be released, which can then be compressed, transported and stored in geological features, such as depleted oil fields, or used as raw material in chemical factories.
Although trees and some microbes can capture CO2 and use it as fuel, humans have struggled to replicate the process on a large scale. Most chemical reactions involving CO2 require expensive catalysts, high temperatures, or high pressures to make it react. The most common use of CO2 as a chemical feedstock is in the formation of urea, which is found in around 90% of the world’s fertilisers.
In the new research, published in the journal Angewandte Chemie, Soon Hong and colleagues from the Institute for Basic Science in South Korea have caught CO2 from exhaust gas and used it for many reactions that make useful chemicals. One type is called alkynyl carboxylic acid, which has many uses such as making food additives. The other, cyclic carbonate, is used to make polymers for cars and electronics.
Cyclic carbonates can also be used in place of phosgene, which is a very reactive and highly toxic chemical that is used as a starting material to make a wide variety of useful products.