In a paper published in a recent issue of the Journal of the American Chemical Society (Sept. 2004), Geoffrey Coates, a Cornell professor of chemistry and chemical biology, and his graduate students Chris Byrne and Scott Allen describe a way to make polymers using limonene oxide and carbon dioxide, with the help of a novel "helper molecule" -- a catalyst developed in the researchers' laboratory.
Limonene is a carbon-based compound produced in more than 300 plant species. In oranges it makes up about 95 percent of the oil in the peel.
In industry, Coates explains, the orange peel oil is extracted for various uses, such as giving household cleaners their citrus scent. The oil can be oxidized to create limonene oxide. This is the reactive compound that Coates and his collaborators used as a building block.
The other building block they used was carbon dioxide (CO2), an atmospheric gas that has been rising steadily over the past century and a half -- due largely to the combustion of fossil fuels -- becoming an environmentally harmful greenhouse gas.
By using their catalyst to combine the limonene oxide and CO2, the Coates group produced a novel polymer -- called polylimonene carbonate -- that has many of the characteristics of polystyrene, a petroleum-based plastic currently used to make many disposable plastic products."
Another thing is: If we plant a lot of orange trees to supply the limonene, they'll be inhaling and recycling a fair share of CO2 as well, in addition to what's commercially extracted directly from flue gasses and the atmosphere. Carbon Dioxide is a valuable co-product of coal power generation and coal-to-liquid conversion. We shouldn't be wasting it, and money, by pumping it all down geologic storage rat holes, we should profitably use it.