diamine

Diamines are organic compounds that contain two amino groups (-NH2) per molecule. They can be aliphatic or aromatic and are typically bases, with two primary amino groups attached to carbon frameworks. As bifunctional amines, they readily react with acids and with isocyanates or epoxides in polymer chemistry. Diamines often exist as colorless liquids or solids at room temperature and can vary in volatility and odor.

Common examples include ethylenediamine (H2N-CH2-CH2-NH2), 1,3-diaminopropane, 1,4-diaminobutane (putrescine), hexamethylenediamine, and phenylenediamines (o-, m-, and p-). These compounds illustrate the range from simple aliphatic diamines to more complex aromatic variants used in specialized applications.

Industrial production of diamines typically involves methods such as catalytic hydrogenation of dinitriles or amination and reduction of dihalides, with the exact route chosen to give the desired backbone and substitution pattern. Diamines are important building blocks in the manufacture of polyamides (nylons), polyurethane foam hardeners and coatings, epoxy resin curing agents, dyes, agrochemicals, and pharmaceutical intermediates.

Safety and handling considerations are important for diamines, as many are corrosive and can irritate skin, eyes, and the respiratory tract. Some diamines can act as sensitizers and pose occupational hazards; appropriate engineering controls and personal protective equipment are advised. They may also exhibit environmental toxicity if released in significant quantities.