Ethylenediamine
Ethylenediamine (abbreviated as en when a ligand) is the organic compound with the formula C2H4(NH2)2. This colorless liquid with an ammonia-like odor is a strongly basic amine. It is a widely used building block in chemical synthesis, with approximately 500,000 tonnes produced in 1998. Ethylenediamine readily reacts with moisture in humid air to produce a corrosive, toxic and irritating mist, to which even short exposures can cause serious damage to health (see safety).
Synthesis
Ethylenediamine is manufactured industrially from 1,2-dichloroethane and ammonia under pressure at 180 °C in an aqueous medium:
In this reaction hydrogen chloride is generated, which forms a salt with the amine. The amine is liberated by addition of sodium hydroxide and can then be recovered by rectification. Diethylenetriamine (DETA) and triethylenetetramine (TETA) are formed as by-products.
Another industrial route to ethylenediamine involves the reaction of ethanolamine and ammonia:
This process involves passing the gaseous reactants over a bed of nickel heterogeneous catalysts.
