1,2-Diaminopropane

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1,2-Diaminopropane
Skeletal formula of 1,2-diaminopropane with some implicit hydrogens shown
Identifiers
CAS number 78-90-0 N
PubChem 6567, 447820 R, 642322 S
ChemSpider 13849260 YesY, 394801 R YesY, 557530 S YesY
EC number 201-155-9
UN number 2258
MeSH 1,2-diaminopropane
ChEBI CHEBI:30630 YesY
RTECS number TX6650000
Beilstein Reference 605274
Gmelin Reference 25709
Jmol-3D images Image 1
Properties
Molecular formula C3H10N2
Molar mass 74.12 g mol−1
Appearance Colourless liquid
Odor Fishy, ammoniacal
Density 870 mg mL−1
Melting point −37.1 °C; −34.9 °F; 236.0 K
Boiling point 119.6 °C; 247.2 °F; 392.7 K
Vapor pressure 1.9 Pa (at 20 °C)
Refractive index (nD) 1.446
Thermochemistry
Specific
heat capacity
C
205.64 J K−1 mol−1
Std molar
entropy
So298
247.27 J K−1 mol−1
Std enthalpy of
formation
ΔfHo298
−98.2–−97.4 kJ mol−1
Std enthalpy of
combustion
ΔcHo298
−2.5122–−2.5116 MJ mol−1
Hazards
GHS pictograms The flame pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) The corrosion pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) The exclamation-mark pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS)
GHS signal word DANGER
GHS hazard statements H226, H302, H312, H314
GHS precautionary statements P280, P305+351+338, P310
EU Index 612-100-00-7
EU classification Corrosive C
R-phrases R10, R21/22, R35
S-phrases S26, S37/39, S45
Flash point 34 °C (93 °F; 307 K)
Explosive limits 1.9–11.1%
LD50
  • 434 mg kg−1 (dermal, rabbit)
  • 2.23 g kg−1 (oral, rat)
Related compounds
Related alkanamines
Related compounds 2-Methyl-2-nitrosopropane
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
 N (verify) (what is: YesY/N?)
Infobox references

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

Preparation[edit]

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

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

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.[2] Alternate reagents for chiral resolution include N-p-toluenesulfonylaspartic acid, N-benzenesulfonylaspartic acid, or N-benzoylglutamic acid.[3]

N,N-Disalicylidene-1,2-propanediamine[edit]

Salpn is a typical metal deactivator.

1,2-Diaminopropane can be converted to N,N′-disalicylidene-1,2-propanediamine, a useful salen-type ligand that is abbreviated salpn. The synthesis is achieved by a condensation reaction of the diamine with salicylaldehyde:

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

Salpn is used as a fuel additive as a metal deactivator in motor oils. Trace metals degrade the fuels by catalyzing oxidation processes that lead to gums and solids. Metal deactivators like salpn form stable complexes with the metals, suppressing their catalytic activity.[4] While salpn 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 salpn forms a highly stable square-planar complex with the metal. This complex is especially stable because salpn is a tetra-dentate ligand with a -2 charge (after deprotonation of the two phenolic groups).[5]

The use of salpn is preferred over the use of ethylenediamine (producing salen), possibly because the propane derivatives has higher solubility.

References[edit]

  1. ^ a b 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. 
  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. 
  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. (2005), "Automotive Fuels", Ullmann's Encyclopedia of Industrial Chemistry, Weinheim: Wiley-VCH 
  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.