Plastic Oranges

A catalyst developed at Cornell University can help limonene oxide derived from citrus fruits combine with the greenhouse gas carbon dioxide to produce organic polymers, according to Geoffrey Coates and his colleagues.


On the road to renewable feedstocks for the chemical industry

Coates and graduate students Chris Byrne and Scott Allen explain that limonene is found naturally in more than 300 plant species and is the main component of the oil from orange peel. Industry currently uses limonene as a scent in household cleaners but might one day be used as the raw material for making the plastic bottle itself. The Cornell catalytic reaction yields poly(limonene carbonate), which has many of the plastic properties of polystyrene, and is made from petroleum-based sources, say the researchers.

"Almost every plastic out there, from the polyester in clothing to the plastics used for food packaging and electronics, goes back to the use of petroleum as a building block," Coates says, "If you can get away from using oil and instead use readily abundant, renewable, and cheap resources, then that's something we need to investigate. What's exciting about this work is that from completely renewable resources, we were able to make a plastic with very nice qualities."


Plastics are not the only fruit

"The group is currently looking to develop more efficient routes to the plastic," Coates told Reactive Reports, "and to fully characterize the properties of this material." Since publishing the limonene oxide work, the researchers have been investigating the conversion of other natural terpenes as potential renewable chemical resources.