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Louis Kuo finds new way to degrade pesticides

October 08, 2001

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    Louis Kuo, associate professor of chemistry and department chair, finds a new way to break down the molecular structure of two pesticides, parathion and paraoxon.

A Lewis & Clark chemistry professor has discovered a new way to degrade dangerous pesticides and possibly chemical warfare agents.

Louis Kuo, associate professor of chemistry and department chair, found a new method to break down the complex molecular structure of two pesticides, parathion and paraoxon. His approach renders the pesticides much less harmful to the environment. The chemical process, which occurs in water, is called hydrolysis.

The Environmental Protection Agency recently banned both pesticides. As organophosphates, these two pesticides are similar to chemical warfare agents.

Parathion and paraoxon are neurotoxins. They are related to the notorious sarin and VX neurotoxins, “albeit a lot less lethal,” noted Kuo.

Given that chemical similarity, Kuo’s research has potential application for the degradation of chemical warfare agents stored by the Army. The hydrolysis process that Kuo discovered may also work under the same conditions in which the Army stores its chemical warfare agents (i.e., in closed, air-free containers).

Kuo’s research could offer solutions to problems associated with storing such chemicals.

The Army’s research office has invited Kuo to submit a full proposal to study the degradation of phosphates found in chemical warfare agents.

In the past, parathion and paraoxon were used on such crops as alfalfa, wheat, barley, corn, cotton, soybean and sunflower. The Biological and Economic Analysis Division of the EPA estimates that about one percent of these crops were treated annually with the pesticides, currently classified as possible human carcinogens.

“In the process of looking into ways to degrade pesticides,” Kuo explained, “I made a chemical that can do it under benign conditions.”

Kuo used a type of organometallic compound, called a metallocene, to carry out the phosphate hydrolysis in water. This is the first known case of an organometallic compound that does this type of chemistry under benign conditions (at neutral pH and 50 degrees Celsius).

“At first, the idea of performing aqueous organometallic reactions in water might seem ridiculous,” writes a journalist for Chemical and Engineering News, “since it goes against the traditional belief that most organometallics are extremely sensitive to traces of air and moisture and rapidly decompose in water.”

Kuo’s research shows that not only are some organometallics stable in water, but they may yield chemical transformations that have environmental benefits in terms of pesticide degradation and benign chemical syntheses.

Last May, as a result of these findings, Kuo received a $34,800 grant from Research Corporation for work at Lewis & Clark with students. The funds cover the costs of his research, student research and all supplies associated with his current study.

In 1994 and 1998, the Petroleum Research Foundation of the American Chemical Society funded two grants—$20,000 and $30,000, respectively—for Kuo’s research project with organometallic reagents.

In the future, Kuo hopes to find a way to modify the parent metallocene so that it works more quickly and can degrade other pesticides and organophosphates.

—by Kathy Carlson ’00

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