If something has mass, then it is made up of molecules, and chances are it includes carbon. Carbon is so central to the human existence that we have an entire field of science devoted specifically to understanding its chemistry- organic chemistry. Over the last 250 years, chemists have been probing chemistry to try to understand how it behaves and exploring the best strategies for synthesizing molecules. However, in this time we have operated almost exclusively on the exergonic side of things- that is to say, we perform reactions in the way that releases energy, i.e., the spontaneous direction. This is akin to water running downhill. However, in principle, it is possible to make water flow up hill. Indeed, nature accomplishes just such a feat in photosynthesis in which she converts energetically spent carbon dioxide into energy rich sugars. While no laws of thermodynamics are broken by nature (as if she could), there are many lessons to be learned about what it takes to perform contra-thermodynamic synthesis. We have been studying the lessons given to us by nature and have even begun emulating her in the lab. Recently, we have used our understanding to accomplish the synthesis of urethanes directly from carbon dioxide in a safe and compelling mild reaction that uses visible light indirectly to facilitate the process. Urethanes ($20 billion USD/year) are an important class of molecules (think polyurethane foams) and are still produced via high energy and highly toxic reagents such as phosgene. The largest chemical disaster in the history of the world occurred in 1984 in Bhophal India, in which highly toxic methyl isocyanate- used to make a methyl urethane, leaked, and injured approximately a half a million individuals, killing many. By using synthetic photosynthesis, we can drive an otherwise unfavorable reaction to completion directly from innocuous carbon dioxide, completely avoiding any toxic reagents. We will distill the essential understanding that makes this possible and share it during this Research on Tap.
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