Ionic liquids could be used to herald the era of plastics recycling, according to work being undertaken in Japan. Akio Kamimura and Shigehiro Yamamoto of Yamaguchi University have found that they can depolymerize polyamide plastics, such as nylon and Kevlar, using an ionic liquid at 300 Celsius, and releasing the original chemical building blocks. The ionic liquid could itself be used five times in processing new batches of polymer. Such a breakthrough could revolutionize plastics recycling and make it as viable commercially and environmentally in the future as scrap steel and glass recycling is today. Writing in the July 5 issue of Organic Letters, the team describes how their lab-scale preliminary experiments could break down nylon-6 into raw caprolactam. "This is the first example of the use of ionic liquids for effective depolymerization of polymeric materials and will open a new field in ionic liquid chemistry as well as plastic recycling," the researchers say.
Recycling ionic liquids