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1,2-Diaminopropane

Identifiers
3D model (JSmol)	Interactive image
ChEBI	CHEBI:30630
ChemSpider	13849260
ECHA InfoCard	100.001.051
CompTox Dashboard (EPA)	DTXSID4021761
InChI InChI=1S/C3H10N2/c1-3(5)2-4/h3H,2,4-5H2,1H3Key: AOHJOMMDDJHIJH-UHFFFAOYSA-N InChI=1/C3H10N2/c1-3(5)2-4/h3H,2,4-5H2,1H3Key: AOHJOMMDDJHIJH-UHFFFAOYAH
SMILES CC(N)CN
Properties
Chemical formula	C3H10N2
Molar mass	74.127 g·mol
Except where otherwise noted, data are given for materials in their standard state (at 25 °C , 100 kPa). Infobox references

1,2-propanediamine is a diamine commonly used as a bidentate ligand in coordination chemistry. Pn is the simplest chiral diammine. The molecules exists as a colorless liquid at room temperature.

Preparation

Industrially, this compound is synthesized by the ammonolysis of 1,2-dichloropropane: This preparation allows for the use of waste chloro-organic compounds to form useful amines using inexpensive and readily available ammonia:

CH₃CHClCH₂Cl + 4NH₃ → CH₃CH(NH₂)CH₂NH₂ + 2NH₄Cl

The racemic mixture of this chiral compound may be separated into enantiomers by conversion into the diastereomeric tartaric acid ammonium salt. After purification of the diastereomer, the diamine can be regenerated by treatment of the ammonium salt with sodium hydroxide. Alternate reagents for chiral resolution include N-p-toluenesulfonylaspartic acid, N-benzenesulfonylaspartic acid, or N-benzoylglutamic acid.

Uses

1,2-propanediamine can be converted to N,N'-disalicylidene-1,2-propanediamine, a useful salen-type ligand. This can be achieved by a condensation reaction of the diamine with salicylaldehyde as follows:

2C₆H₄(OH)CHO + CH₃CH(NH₂)CH₂NH₂ → ₂CH₃CHNCH₂N + 2H₂O

N,N’-Disalicylidene-1,2-propanediamine

N,N’-Disalicylidene-1,2-propanediamine is an important derivative of 1,2-diaminopropane that is used as a fuel additive as a “metal deactivating compound” in motor oils. Trace metals in fuels catalyze oxidation reactions, which degrade the fuels. Metal deactivators form stable complexes with the metals, so their catalytic activity is lost. While N,N-disalicylidene-1,2-propanediamine forms stable chelate complexes with many metals including copper, iron, chromium, and nickel, it is the coordination with copper that makes it a popular choice as a fuel additive. Copper has the highest catalytic activity in fuel, and N,N-disalicylidene-1,2-propanediamine forms a highly stable square-planar complex with the metal. This complex is especially stable because N,N’-disalicylidene-1,2-propanediamine is a tetra-dentate ligand with a -2 charge which forces a square-planar geometry, and copper(II) complexes prefer this orientation.

The use of the 1,2-propanediamine ligand in producing the N,N'-disalicylidene is preferred over the use of ethylenediamine (producing salen) possibly due to the electron donating nature of the extra methyl group, causing greater electron density on the main chain of the molecule and increasing the complexation of the molecule with copper.

References

1. ^ Bartkowiak, M.; Lewandowski, G.; Milchert, E.; Pelech, R. (2006). "Optimization of 1,2-Diaminopropane Preparation by the Ammonolysis of Waste 1,2-Dichloropropane". Ind. Eng. Chem. Res. 45: 5681–5687. doi:10.1021/ie051134u.{{cite journal}}: CS1 maint: multiple names: authors list (link)
2. Romanowski, G.; Wera, M. (2010). "Mononuclear and dinuclear chiral vanadium(V) complexes with tridentate Schiff bases derived from R(-)-1,2-diaminopropane: Synthesis, structure, characterization and catalytic properties". Polyhedron. 29: 2747–2754. doi:10.1016/j.poly.2010.06.030.{{cite journal}}: CS1 maint: multiple names: authors list (link)
3. JP application 04-018057, Sakie, N. & Haruyo, S., "Production of Optically Active 1,2-propanediamine" 
4. ^ Dabelstein, W.; Reglitzky A.; Schutze A.; Reders, K. "Automotive Fuels". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. ISBN 978-3-527-30673-2.{{cite encyclopedia}}: CS1 maint: multiple names: authors list (link)
5. Evans, D. A.; Miller, S. J.; Lectka, T.; von Matt. P. (1999). "Chiral Bis(oxazoline)copper(II) Complexes as Lewis Acid Catalysts for Enantioselective Diels-Alder Reaction". J. Am. Chem. Soc. 121: 7559–7573. doi:10.1021/ja991190k.{{cite journal}}: CS1 maint: multiple names: authors list (link)

• Polyamines
• Chelating agents
• Fuel antioxidants
• Corrosion inhibitors