DEET or N,N-diethyl- meta -toluamide, C12H17ON, nearly odorless, colorless to clear yellow oily liquid that boils at 111°C. DEET was developed by the U.S. Army in 1946 for use as an insect repellent and is now a common ingredient in many commercial insect repellents. Extensive testing has shown that products containing DEET provide the best protection against mosquito bites and deer ticks. It is also known as diethyltoluamide.
The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2012, Columbia University Press. All rights reserved.