This week's In The News highlights the discovery of a new process that could separate problematic chemicals from ionic liquids. In industry, chemical reactions are performed in toxic organic solvents and some can form carbon dioxide and other greenhouse gases. Specifically, the vapor pressure of these organic solvents is hazardous because these "solvents evaporate easily into the air." The effects of such a reaction are that factory workers may inhale them and "the solvents add to damage of the earth's atmosphere, because organic solvents eventually will oxidize and create carbon dioxide, a greenhouse gas with potential impact on global warming". Published in the May 6, 1999 issue of Nature, scientists Joan Brennecke, Eric Beckman and other team members discuss how two "benign compounds together can perform certain chemical separations now done only by noxious organics." In the process discussed in Nature these scientists enforced supercritical (high pressure that causes liquid and gas to combine into one fluid phase) carbon dioxide into a solution of naphthalene (an organic chemical) dissolved in an ionic liquid (liquid salts at room temperature made of organic cations and inorganic anions). This pulled the naphthalene out with it while leaving behind the ionic liquid. As this mixture was depressurized, the "carbon dioxide returned to its gaseous form, leaving pure solid naphthalene." Ionic liquids and carbon dioxide are not considered perilous because ionic liquids do not evaporate and carbon dioxide is "considered to be an environmentally benign solvent because it is nontoxic and nonflammable and isn't being created in the process; what already exists is simply being used." Scientists Brennecke and Beckman believe this process could be useful for other chemicals. The ten resources listed provide news summaries, background information, and resources related to this recent discovery.
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