Ethylenediamine

Ethylenediamine 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 500,000,000 kg being produced in 1998.^[1]

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Synthesis

Ethylenediamine is manufactured by reacting ammonia and 1,2-dichloroethane. The reaction yields the mixture of ethylenediamine and the linear polyamines. A simplified equation would be:

ClCH₂CH₂Cl + 4 NH₃ → H₂NCH₂CH₂NH₂ + 2 NH₄Cl

Applications

Ethylenediamine is used in large quantities for production of many industrial chemicals. It forms derivatives with carboxylic acids (including fatty acids), nitriles, alcohols (at elevated temperatures), alkylating agents, carbon disulfide, and aldehydes and ketones. Because of its bifunctional nature, having two amines, it readily forms heterocycles such as imidazolidines.

Precursor to chelating agents

The most prominent derivative of ethylenediamine is EDTA, which is derived from ethylenediamine via a Strecker synthesis involving cyanide and formaldehyde. Hydroxyethylethyelenediamine is another commercially significant chelating agent. The salen ligands, derived from the condensation of salicaldehydes and ethylenediamine, are popular chelating agents in the research laboratory although not commercially significant.^[1]

Precursor to pharmaceuticals and agrichemicals

Numerous bio-active compounds contain the N-CH₂-CH₂-N linkage, including aminophylline and some antihistamines.^[2] Salts of ethylenebisdithiocarbamate are commercially significant fungicides under the brandnames Maneb, Mancozeb, Zineb, and Metiram. Some imidazoline-containing fungicides are derived from ethylenediamine.^[1]

Role in polymers

Ethylenediamine, by virtue of its bifunctionality (i.e. it contains two reactive amines) is widely used in diverse polyester formulations. Condensates derived from formaldehyde are plasticizers. It is widely used in the production of polyurethane fibers. The PAMAM class of dendrimers are derived from ethylenediamine.^[1]

Tetraacetylethylenediamine

The bleaching activator tetraacetylethylenediamine is generated from ethylenediamine. The derivative N,N-ethylenebis(stearamide) (EBS) is a commercially significant mold-release agent and a surfactant in gasoline and motor oil.

Specialized applications

• as a solvent, it is miscible with polar solvents and is used to solubilize proteins such as albumins and casein. It is also used in certain electroplating baths
• as a corrosion inhibitor in paints and coolants.
• ethylenediamine dihydroiodide (EDDI) is added to animal feeds as a source of iodide.
• chemicals for color photography developing, binders, adhesives, fabric softeners, curing agents for epoxys, and dyes.

Coordination chemistry

Ethylenediamine is the prototypical chelating ligand for coordination compounds, such as [Co(ethylenediamine)₃]³⁺.

Ethylenamines

Ethylenediamine is the first member of the so-called polyethylene amines, other members being:

• Diethylenetriamine, abbreviated dien or DETA, (H₂N-CH₂CH₂-NH-CH₂CH₂-NH₂, an analog of diethylene glycol)
• Triethylenetetramine, abbreviated trien or TETA, (H₂N-CH₂CH₂-NH-CH₂CH₂-NH-CH₂CH₂-NH₂)
• Tetraethylenepentamine, abbreviated TEPA, (H₂N-CH₂CH₂-NH-CH₂CH₂-NH-CH₂CH₂-NH-CH₂CH₂-NH₂),
• Pentaethylenehexamine, abbreviated PEHA, (H₂N-CH₂CH₂-NH-CH₂CH₂-NH-CH₂CH₂-NH-CH₂CH₂-NH-CH₂CH₂-NH₂), up to polyethylene amine. Similarly piperazine is an analogue of dioxane.

Related diamines

In terms of quantities produced, ethylenediamine is the most significant diamine (aside from diaminohexane, which is a precursor to Nylon 66). Related derivatives of ethylenediamine include tetramethylethylenediamine, abbreviated (TMEDA), (CH₃)₂N-CH₂CH₂-N(CH₃)₂

and tetraethylethylenediamine, abbreviated (TEEDA), (C2H5)2N-CH2CH2-N(C2H5)2

Safety

Ethylenediamine exposure can cause the skin to become irritated. It was used in commercially available skin products including Mycolog cream.^[3] Ethylenediamine has a half-life of about 30 minutes and a small volume of distribution of 0.133 liters/kg. After oral administration its bioavailability is about 0.34, due to a substantial first-pass effect. Less than 20% is eliminated by renal excretion.^[4]

See also

• Diethylenetriamine
• Triethylenetetramine
• Polyethylene amine

References