Carbon Capture Methods Utilizing Organosulfur Compounds

The US National Academy of Sciences and The Royal Society have recently released a detailed report on the causes and effects of global climate change.1 This report states that the Earth’s climate is rapidly changing due to human activity. Specifically, the burning of fossil fuels to satisfy the energy demands of rising global population has resulted in unprecedented levels of greenhouse gasses in the atmosphere. These high levels of greenhouse gasses are serving to warm the surface of the planet resulting in extreme weather events. Thus, controlling the atmospheric CO2 level is motivating a great deal of scientific research in the area of carbon capture and storage (CCS).

Despite the great strides being made in the areas of alternative energy and solar-energy conversion, consumption of fossil fuels for energy generation will likely continue into the foreseeable future. This is primarily motivated by economic factors inasmuch as fossil fuels are a proven resource base with robust harvesting and distribution infrastructure.2 Presently, there are more than 8,000 stationary CO2 emission sources with an annual output of 13,466 megatons of CO2 per year.2 In this context, development of systems that ameliorate the output of greenhouse gasses from stationary CO2 sources, such as coal and natural gas burning power plants, is urgently needed.

In this document the utility of sulfur nucleophiles for CCS schemes is explored. The main thrust of the research has been utilizing electrogenerated sulfur nucleophiles to capture CO2, which can be electrochemically recovered from the resulting thiocarbonates while concomitantly regenerating the masked capture agent. Further, a temperature swing CO2 capture scheme that employs benzylthiolate as the CO2 sorbent is proposed and methods of manipulating the release temperature and kinetics were investigated. These reports represent the first application of organosulfur compounds toward CCS technologies and there are a number of newly reported compounds. The appendix deviates from the theme of the first four chapters to describe the functionalization of poly(2,6-dimethyl-1,4-phenylene oxide) with ferrocene moieties by the copper catalyzed azide-alkyne coupling reaction. This material is discussed within the context of anion recognition and sensing applications.