At room temperature, the lower aliphatic amine is the gas, and more than the amine is liquid, and the high fat amine is solid. The lower amines have unpleasant or unpleasant smells. For example, there is a fishy odor of trimethylamine, ethylenediamine (Humic Amine) and glutaraldehyde (amine) have the stench of rotting animal carcasses. The high amine is not easy to evaporate, the smell is very small. Aromatic amine is a high boiling point liquid or low melting point solid, although the odor is smaller than the fat amine, but the toxicity is relatively large, whether inhaled their vapor or skin contact will cause poisoning. Some aromatic amines, such as β-naphthalene amine, and benzidine have carcinogenic effects.

Because the nitrogen atoms in the amine molecule form hydrogen bonds with water, the solubility of low fat amine in water is relatively large. The hydrogen bond between the amines and the secondary amines can be formed, but because the electronegativity of the nitrogen atom is less than that of the oxygen atom, the hydrogen bonding capacity of the amine is weaker than that of the relative molecular mass.

Amine is similar to ammonia, the nitrogen atoms in the molecule contain an electronic pair that is not common, and can be combined with H to show alkalinity.

R-nh2+hcl≒r-nh3cl

Alkaline Ionization constant KB or other negative pair value PKB indicates that the larger the KB value or the smaller the PKB value, the stronger the amine alkalinity.