Aroma products generally contain ethyl crotonate, trans- (ethyl but-2-enoate) as one of their components. A clear, colorless liquid with a pungent odor, this organic compound is highly flammable ...

The active ingredient is stated to be 2 : 4-dinitro-6- (l-methyl-n-heptyl)phenyl crotonate, although some of the phenol is usually present in the free state.