Diethylamine appears as a clear colorless liquid with an ammonia-like odor. Density 5.9 lb / gal. Flash point -15°F. A respiratory irritant. Corrosive to the eyes and skin. Vapors heavier than air. Toxic oxides of nitrogen produced during combustion.Diethylamine is a secondary aliphatic amine where both N-substituents are ethyl. It is a conjugate base of a diethylammonium.