
Reducing the
Use of Organic SolventsBy Linda McGraw April 5, 2001Agricultural Research Service (ARS)
scientists in Peoria, Ill., are coupling two environmentally friendly
techniques to reduce or eliminate the use of toxic organic solvents in the
processing of agricultural commodities. The U.S.
Environmental Protection Agency has called for a reduction in the amount of
toxic solvents released into the environment, which has impacted industrial
manufacturers. Solutions called ionic liquids, salt-like fluids at room temperature, are
safer to use than organic solvents like hexane in research laboratories,
according to ARS biochemist Joseph A. Laszlo at the
National Center for Agricultural
Utilization Research in Peoria. In the past, researchers had to use
solvents to get enzymes to act as a catalyst for chemical reactions. Now, ionic
liquids can be used in place of solvents. Laszlo and ARS chemist David L. Compton made ionic liquids in their
laboratory. They are the first researchers to perform enzymatic reactions in
ionic liquids in combination with supercritical carbon dioxide (CO2). They
tested the liquids as a solvent for the enzyme chymotrypsin with a commonly
used laboratory substrate. This enzyme may catalyze reactions needed to
manufacture important chemical ingredients in drugs and skin care products. Laszlo says that combining ionic liquids and supercritical CO2 results in a
superior processing method, which is better than either one alone. In the
technique, CO2 is heated and compressed to the point that it becomes both
liquid and gas, which is the supercritical state. Laszlo reported these findings at the 221st annual meeting of the
American Chemical Society meeting in San
Diego, April 1-5, where he participated in a 5-day symposium on the development
of ionic liquids. ARS is the chief scientific research agency for the
U.S. Department of Agriculture. Scientific contact: Joseph A. Laszlo, ARS National Center for
Agricultural Utilization Research, Peoria, Ill., phone (309) 681-6322, fax
(309) 681-6685, [email protected]. U.S. Department of Agriculture |