Each year, polymer makers around the world produce roughly 4 billion kilograms of nylon-6, a type of nylon used to make items ranging from clothing to carpets to car parts. Now, researchers have devised a one-step process for making the primary ingredient of nylon-6, a simplification that could eliminate an abundant by-product of the industry's current two-step process.
As its name implies, nylon-6 has six carbon atoms in its basic molecular unit, or monomer, which is called caprolactam. This monomer polymerizes into long chains to form nylon-6. The chemical reactions that produce caprolactam are cumbersome, says John Meurig Thomas, a solid-state chemist at the University of Cambridge in England.
The widely used two-step process requires large amounts of sulfuric acid, which is corrosive. What's more, for every kilogram of caprolactam manufactured, says chemist Robert Raja, also of the University of Cambridge, 4 kg of ammonium sulfate are generated. Although this by-pro