CHAPEL HILL -- An "exciting" new industrial process for separating liquid chemicals from one another -- a technique that promises to cut release of toxic substances into the environment -- has been developed by chemists at the University of North Carolina at Chapel Hill and colleagues.
"Liquid-liquid separations are an important process in many manufacturing industries -- pharmaceuticals, textiles, fine chemicals and natural products such as taxol, an extract from the yew tree that helps fight cancer," said Dr. Joseph M. DeSimone, Mary Ann Smith professor of chemistry at UNC-CH. "Very often these processes need to use organic solvents which are not good for our environment. That's because the solvents are either toxic or flammable or both, and they are expensive.
"What we invented was a process that allows carbon dioxide to be used to replace these organic solvents in liquid-liquid extractions."
A report on the chemical process appears in the Sept. 25 issue of Nature, a scientific journal.
Besides DeSimone, UNC-CH authors are Dr. Andrew I. Cooper, a former postdoctoral fellow; graduate student Jim McLain; Edward T. Samulski, professor and chair of chemistry; Dr. Andrey Dobrynin, postdoctoral research associate; Dr. Michael Rubenstein, professor of chemistry; and graduate student Amy Burke. Other authors include Drs. David Londono and George Wignall of Oak Ridge National Laboratory and John Frechet of the University of California at Berkeley.
The new work employs carbon dioxide, or CO2, because it is a common, inexpensive and harmless gas, DeSimone said. It is the gas humans and animals exhale and also that forms the bubbles in soda and champagne.
The process involves introducing soap-like surfactants into pressurized,
or liquid, carbon dioxide that form a 'microenvironment' which allows substances
normally not soluble in the gas to become soluble. After pulling the desired
compound away from
Contact: David L. Williamson
University of North Carolina at Chapel Hill