Crystal could generate pure hydrogen fuel.The bizarre behavior of an organic crystal called calixarene could help drive a hydrogen economy, suggests a new study. Researchers describe a crystal that, when exposed to air, absorbs molecules such as carbon dioxide carbon dioxide, chemical compound, CO2, a colorless, odorless, tasteless gas that is about one and one-half times as dense as air under ordinary conditions of temperature and pressure. , carbon monoxide carbon monoxide, chemical compound, CO, a colorless, odorless, tasteless, extremely poisonous gas that is less dense than air under ordinary conditions. It is very slightly soluble in water and burns in air with a characteristic blue flame, producing carbon dioxide; , oxygen, and nitrogen. The crystal consists of two calixarene molecules joined together, resembling a pair of cups attached at a their open ends to leave a cavity inside. Chemist (jargon) chemist - (Cambridge) Someone who wastes computer time on number crunching when you'd far rather the computer were working out anagrams of your name or printing Snoopy calendars or running life patterns. May or may not refer to someone who actually studies chemistry. Jerry Atwood of the University of Missouri-Columbia and his colleagues discovered calixarene's behavior after adding a drop of nitrobenzene nitrobenzene, C6H5NO2, very poisonous, flammable, pale yellow, liquid aromatic compound with an odor like that of bitter almonds. It is sometimes called oil of mirbane or nitrobenzol. Nitrobenzene melts at 5.85°C;, boils at 210. to a layer of crystal material on a glass slide. Suddenly, the crystal began to bubble vigorously, says Atwood, indicating that molecules of nitrobenzene somehow had migrated into the crystal and forced out gas molecules. When the researchers exposed the crystals to a stream of gas containing equal amounts of hydrogen and carbon dioxide, the calixarene did something even more surprising: It selectively absorbed carbon dioxide, leaving the hydrogen behind. This separation method could be a boon Boon A general term that refers to a benefit or improvement for investors. This can include such things as increased dividends, a stock market rally and stock buybacks. Notes: for fuel cells that rely on hydrogen, such as those proposed for cars. Impurities in hydrogen, including carbon dioxide, decrease a fuel cell's efficiency and durability. Hydrogen-production plants use costly separation technologies to remove the impurities. Filtering hydrogen through calixarene crystals could offer a relatively inexpensive and more efficient alternative, says Atwood. Just how the carbon dioxide gets into the crystal's cavity remains unknown. Atwood suspects that the crystal's lattice (theory) lattice - A partially ordered set in which all finite subsets have a least upper bound and greatest lower bound. This definition has been standard at least since the 1930s and probably since Dedekind worked on lattice theory in the 19th century; though he may not structure shifts slightly upon contact with carbon dioxide and lets the molecule enter. "It's like going through a turnstile," he says. The researchers describe the crystals in the May 24 Angewandte Chemie.--A.G. |
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