1,2-Diaminopropane

Preparation

Industrially, this compound is synthesized by the ammonolysis of 1,2-dichloropropane:

:CHCHClCHCl + 4 NH → CHCH(NH)CHNH + 2 NHCl

This preparation allows for the use of waste chloro-organic compounds to form useful amines using inexpensive and readily available ammonia.

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-Diaminopropane is used in the synthesis of N,N-disalicylidene-1,2-propanediamine, a salen-type ligand, usually abbreviated as salpn, that is used as a metal deactivating additive in motor oils.

Related compounds and derivatives

1,2-Diaminopropane forms coordination complexes similar to tris(ethylenediamine)cobalt(III). Owing to the presence of the methyl groups, [Co(pn)3]3+ can exist as 24 stereoisomers.

Two chiral 1,2-diamines are 1,2-diaminocyclohexane and 2,3-diaminobutane. The chiral diastereomers of those diamines are C2-symmetric.

References

References

1. (2006). "Optimization of 1,2-Diaminopropane Preparation by the Ammonolysis of Waste 1,2-Dichloropropane". Ind. Eng. Chem. Res..
2. (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.
3. "Production of Optically Active 1,2-propanediamine".
4. "Automotive Fuels".
5. (1974). "The Tris[(+-)-1,2-propanediamine]cobalt(III) System". Acta Chemica Scandinavica.