下面为大家整理的是一篇科技方面的
A Chemist Comes Very Close to a Midas Touch
In a lab in Princeton University’s ultra-sleek chemistry building, researchers toil in a modern-day hunt for an elusive power: alchemy.
Throughout the centuries, alchemists tried in vain to transform common metals like iron and lead intoprecious ones like gold or platinum. Today,Paul Chirik, a professor of chemistry at Princeton, has managed a new twist on the timeworn pursuit.
Dr. Chirik, 39, has learned how to make iron function like platinum, in chemical reactions that are crucialto manufacturing scores of basic materials. While he can’t, sadly, transmute a lump of iron ore into a pile of valuable jewelry, hisversion of alchemy is far more practical, and the implications are wide-ranging.
The process could herald a new era of flexible manufacturing technologies, while enabling companies to steer clear of scarceelements as prices rise or obtaining them becomes environmentally or geopolitically risky.
“No chemist would think lithium was in short supply,” Dr. Chirik said, “but what happens if you put a lithium battery in every car? This is why chemistry needs to be ahead of the curve. We need to have adaptable solutions.”
Despite the cost and relative scarcity of precious metals — iridium, platinum, rhodium — we rely on them to manufactureproducts from denim to beer, pharmaceuticals to fuel cells. The elements are used as catalysts, substances that kick off or enablechemical reactions.
Dr. Chirik’s work involves dissolved catalysts, which are mixed into the end product. The molecules of the catalyst dissipateduring the reaction. For instance, a solution containing platinum is used to make silicone emulsifiers, compounds that in turn feed products like makeup, cookware and glue. Tiny amounts of the expensive metal are scattered in all these things; your jeans, forinstance, contain unrecoverable particles of platinum.
“We’re not about to run out of platinum,” said Matthew Hartings, a chemist at American University in Washington, “but thisprocess spends that platinum in a nonsustainable way.”
Dr. Chirik’s chemistry essentially wraps an iron molecule in another, organic molecule called a ligand. The ligand alters thenumber of electrons available to form bonds. It also serves as a scaffold, giving the molecule shape. “Geometry is really importantin chemistry,” Dr. Hartings said. Dr. Chirik’s “ligands help the iron to be in the right geometry to help these reactions along.”
In addition to iron, Dr. Chirik’s lab also works with cobalt, which sits beside iron on the periodic table. Using cobalt, Dr. Chirik said, the scientists have generated “a whole new reaction that no one has ever seen before.” It produces new types of plasticsusing very inexpensive starting materials.
But the price of cobalt has shot up since the lab first began its research, thanks to the element’s use in the flat batteries that power gadgets like iPads and iPhones.
“The iPad has completely changed the price of cobalt,” Dr. Chirik said, “so something that once was garbage is now valuable.”
While the rising cost may undermine the economic incentive to use Dr. Chirik’s cobalt-fueled materials, it seems to perfectlyunderscore his basic point about the need for flexibility.
“There’s a broad appeal and logic to focusing on more abundant elements in designing catalysts,” said Roderick Eggert, aprofessor of economics and business at the Colorado School of Mines.
A vast majority of the chemicals we manufacture and then use to make other products require catalysts. And a lot of catalysts use so-called noble metals like platinum, palladium and rhodium, which are expensive. A pound of platinum costs about $22,000. A pound of iron, meanwhile, costs about 50 cents.
As an undergraduate chemistry major, Dr. Chirik worked on reactions that used iridium as a catalyst. A pound of iridium costs about $16,000. Dr. Chirik’s boss kept the iridium-based compound locked in a desk drawer.
“You had to walk from his office to the lab holding it with two hands, and not talk to anyone,” Dr. Chirik recalled. Theexperience left him with the seed of an idea, he said. “Why can’t we do this with something cheaper?”
On a spring afternoon at the Princeton lab, a graduate student toiled away at a glovebox, a vacuum chamber that prevents the iron from rusting. Rust is a potential downside of using iron in manufacturing, and controlling it could prove challenging andexpensive. “We’re not talking about making a dish of spaghetti at home,” Dr. Chirik said, referring to the volume of chemicalsinvolved when doing reactions on an industrial scale. It remains to be seen, he said, whether concerns about the use of an “airsensitive” substance outweigh concerns about the costs and environmental impact of precious metals.
这篇关于化学家寻找点石成金的SAT阅读材料的故事，字数不是很多，但是非常完整，而且生词量也不是很大。大家完全可以在备考之余作为休息的时候进行阅读，只要能够长期积累下来就会有不同程度的收获的。