SAPS: Stanford scientists use novel approach to get ‘green’ plastics from CO2, ag-waste mix

Number 6 in the Sustainable Agricultural Practices Series.

Researchers at Stanford University are working their magic: For example, turning inedible plant waste in conjunction with carbon dioxide into usable, sustainable plastic.

Typically needed in the production of plastics and other products is petroleum. What makes this development so special and promising is that, by utilizing this new plastic-making method, the need for petroleum is now less. Not just this, but the carbon dioxide used here isn’t released into the atmosphere and instead goes into the plastic-making process and, what’s more, that plastic is, itself, renewable.

So, what’s behind – or driving – this research?

As many of today’s products are petroleum-based (that is, made using petroleum or petroleum byproducts), as this relates to the ongoing research in question, Stanford Assistant Professor of Chemistry Matthew Kanan and graduate student Aanindeeta Banerjee, are in search of finding ways to manufacture plastic and other products such as polyester that are more renewable.

Mark Shwartz writes in: “Stanford scientists make renewable plastic from carbon dioxide and plants: The new technology could provide a green alternative to petroleum-based plastic bottles and other polyester products,” a Mar. 9, 2016 Stanford University press release, “Stanford scientists have discovered a novel way to make plastic from carbon dioxide (CO2) and inedible plant material, such as agricultural waste and grasses. Researchers say the new technology could provide a low-carbon alternative to plastic bottles and other items currently made from petroleum.”

“Instead of using sugar from corn to make FDCA [2-5-Furandicarboxylic acid], the Stanford team has been experimenting with furfural, a compound made from agricultural waste that has been widely used for decades,” Shwartz continues. “About 400,000 tons are produced annually for use in resins, solvents and other products.

“But making FDCA from furfural and CO2 typically requires hazardous chemicals that are expensive and energy-intensive to make.”

As a means to get around this, carbonate is substituted with the resulting compound being a far more benign one, according to Shwartz.

Specifics

In the approach taken here, “… Banerjee … combined carbonate with CO2 and furoic acid, a derivative of furfural. She then heated the mixture to about 290 degrees Fahrenheit (200 degrees Celsius) to form a molten salt.

“The results were dramatic. After five hours, 89 percent of the molten-salt mixture had been converted to FDCA. The next step, transforming FDCA into PEF plastic, is a straightforward process that has been worked out by other researchers, Kanan said,” Shwartz wrote.

And, as for PEF or polyethylene furandicarboxylate, this is formulated by combining ethylene glycol and the FDCA compound.

PET (polyethylene terephthalate), on the other hand, is a polymer, known more commonly as polyester, according to Shwartz, and a healthy 50 million tons of it annually is used in electronics, fabrics, personal-care-products and recyclable-beverage-container manufacturing.

“PET is made from two components, terephthalic acid and ethylene glycol, which are derived from refined petroleum and natural gas. Manufacturing PET produces significant amounts of CO2, a greenhouse gas that contributes to global warming,” Shwartz, of Stanford University’s Precourt Institute for Energy, adds.

Because carbon dioxide is needed to produce PEF, the real beauty of this is that with this substance exists the potential for a significant reduction in the production and release into the atmosphere of GHG. And, perhaps, the icing on the cake is the notion that carbon dioxide needed in PEF production, could come from industry or the energy-producing sector as Shwartz offers, or both.

The press release in question author further notes: “Kanan and colleagues have also begun to apply their new chemistry to the production of renewable fuels and other compounds from hydrogen and CO2.”

Expect more promising developments ahead.

Leave a Comment