Dimethylamine

From Wikipedia, the free encyclopedia - View original article

Dimethylamine
Identifiers
CAS number124-40-3 YesY
PubChem674
ChemSpider654 YesY
UNIIARQ8157E0Q YesY
EC number204-697-4
UN number1032
KEGGC00543 YesY
MeSHdimethylamine
ChEBICHEBI:17170 YesY
ChEMBLCHEMBL120433 YesY
RTECS numberIP8750000
Beilstein Reference605257
Gmelin Reference849
3DMetB00125
Jmol-3D imagesImage 1
Properties[3][4]
Molecular formula(CH3)2NH
AppearanceColorless gas
OdorIchtyal, ammoniacal
Melting point

-93 °C, 180.15 K, -135 °F

Boiling point

7-9 °C, 280-282 K, 44-48 °F

Solubility in water3.540 kg L−1
log P−0.362
Vapor pressure170.3 kPa (at 20 °C)
kH310 μmol Pa−1 kg−1
Acidity (pKa)10.64[2]
Basicity (pKb)3.36
Thermochemistry
Std enthalpy of
formation
ΔfHo298
−21–−17 kJ mol−1
Hazards
GHS pictogramsThe 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 wordDANGER
GHS hazard statementsH220, H302, H315, H318, H332, H335
GHS precautionary statementsP210, P261, P280, P305+351+338
EU Index612-001-00-9
EU classificationFlammable F+ Harmful Xn
R-phrasesR12, R20, R37/38, R41
S-phrases(S2), S16, S26, S39
NFPA 704
NFPA 704.svg
4
3
0
Flash point−6 °C
Autoignition
temperature
401 °C
Explosive limits2.8–14.4%
Related compounds
Related amines
Related compounds
 YesY (verify) (what is: YesY/N?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references
 
Jump to: navigation, search
Dimethylamine
Identifiers
CAS number124-40-3 YesY
PubChem674
ChemSpider654 YesY
UNIIARQ8157E0Q YesY
EC number204-697-4
UN number1032
KEGGC00543 YesY
MeSHdimethylamine
ChEBICHEBI:17170 YesY
ChEMBLCHEMBL120433 YesY
RTECS numberIP8750000
Beilstein Reference605257
Gmelin Reference849
3DMetB00125
Jmol-3D imagesImage 1
Properties[3][4]
Molecular formula(CH3)2NH
AppearanceColorless gas
OdorIchtyal, ammoniacal
Melting point

-93 °C, 180.15 K, -135 °F

Boiling point

7-9 °C, 280-282 K, 44-48 °F

Solubility in water3.540 kg L−1
log P−0.362
Vapor pressure170.3 kPa (at 20 °C)
kH310 μmol Pa−1 kg−1
Acidity (pKa)10.64[2]
Basicity (pKb)3.36
Thermochemistry
Std enthalpy of
formation
ΔfHo298
−21–−17 kJ mol−1
Hazards
GHS pictogramsThe 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 wordDANGER
GHS hazard statementsH220, H302, H315, H318, H332, H335
GHS precautionary statementsP210, P261, P280, P305+351+338
EU Index612-001-00-9
EU classificationFlammable F+ Harmful Xn
R-phrasesR12, R20, R37/38, R41
S-phrases(S2), S16, S26, S39
NFPA 704
NFPA 704.svg
4
3
0
Flash point−6 °C
Autoignition
temperature
401 °C
Explosive limits2.8–14.4%
Related compounds
Related amines
Related compounds
 YesY (verify) (what is: YesY/N?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Dimethylamine is an organic compound with the formula (CH3)2NH. This secondary amine is a colorless, flammable gas with an ammonia-like odor. Dimethylamine is commonly encountered commercially as a solution in water at concentrations up to around 40%. In 2005, an estimated 270,000 tons were produced industrially,[5] but it is also found as a natural product.

Structure and properties[edit]

The molecule consists of a nitrogen atom with two methyl substituents and one proton. Dimethylamine is a weak base and the pKa of the ammonium salt CH3-NH2+-CH3 is 10.73, a value above methylamine (10.64) and trimethylamine (9.79).

Dimethylamine reacts with acids to form salts, such as dimethylamine hydrochloride, an odorless white solid with a melting point of 171.5 °C. Dimethylamine is produced by catalytic reaction of methanol and ammonia at elevated temperatures and high pressure:[6]

2 CH3OH + NH3 → (CH3)2NH + 2 H2O

Natural Occurrence[edit]

Dimethylamine is found quite widely distributed in animals and plants, and is present in many foods at the level of a few mg/kg.[7]

Uses[edit]

Dimethylamine is a precursor to several industrially significant compounds.[5][8] It reacts with carbon disulfide to give dimethyl dithiocarbamate, a precursor to a family of chemicals widely used in the vulcanization of rubber. The solvents dimethylformamide and dimethylacetamide are derived from dimethylamine. It is raw material for the production of many agrichemicals and pharmaceuticals, such as dimefox and diphenhydramine, respectively. The chemical weapon tabun is derived from dimethylamine. The surfactant lauryl dimethylamine oxide is found in soaps and cleaning compounds. Unsymmetrical dimethylhydrazine, a rocket fuel, is prepared from dimethylamine.

Biochemistry[edit]

The German cockroach utilizes dimethylamine as a pheromone for communication.[9]

It is an attractant for boll weevils.[10]

Dimethylamine undergoes nitrosation under weak acid conditions to give dimethylnitrosamine. This animal carcinogen has been detected and quantified in human urine samples and it may also arise from nitrosation of dimethylamine by nitrogen oxides present in acid rain in highly industrialized countries.[citation needed]

Toxicology[edit]

The toxicology of dimethylamine is discussed as part of a NIH monograph concerning dimethylamine borane. LD50: 736 mg/kg (mouse, i.p.); 316 mg/kg (mouse, p.o.); 698 mg/kg (rat, p.o.); 3900 mg/kg (rat, dermal); 240 mg/kg (guinea pig or rabbit, p.o.). [11]

The unattributed LD (lethal dose) given in the Merck index for i.v. administration to rabbits, 4000 mg/kg, is unexpectedly high, and appears to be inconsistent with values given above.[10]

See also[edit]

References[edit]

  1. ^ "dimethylamine - Compound Summary". PubChem Compound. USA: National Center for Biotechnology Information. 16 September 2004. Identification. Retrieved 21 October 2011. 
  2. ^ Hall, H.K. (1957). J. Am. Chem. Soc. 79: 5441. doi:10.1021/ja01577a030. 
  3. ^ "Dimethylamine". NIST Chemistry WebBook. USA: National Institute of Standards and Technology. Retrieved 21 October 2011. 
  4. ^ "Dimethylamine 38931 - ≥99.0%". Aldrich. Sigma-Aldrich Co. Retrieved 21 October 2011. 
  5. ^ a b A. B. van Gysel, W. Musin "Methylamines" in Ullmann's Encyclopedia of Industrial Chemistry, 2005 Wiley-VCH Verlag, Weinheim. doi:10.1002/14356007.a16 535
  6. ^ Corbin D.R.; Schwarz S.; Sonnichsen G.C. (1997). "Methylamines synthesis: A review". Catalysis Today 37 (2): 71–102. doi:10.1016/S0920-5861(97)00003-5. 
  7. ^ G. B. Neurath et al. (1977). "Primary and secondary amines in the human environment." Fd. Cosmet. Toxicol. 15 275-282.
  8. ^ Ashford's Dictionary of Industrial Chemicals, 3rd edition, 2011, pages 3284-3286
  9. ^ Zhang AQ, Mitchell SC, Smith RL (November 1998). "Dimethylamine formation in the rat from various related amine precursors". Food Chem. Toxicol. 36 (11): 923–7. doi:10.1016/S0278-6915(98)00074-X. PMID 9771553. 
  10. ^ a b The Merck Index, 10th Ed. (1983), p.470, Rahway: Merck & Co.
  11. ^ Chemical Information Profile for Dimethylamine Borane, National Toxicology Program, NIEHS, NIH (2008), p.4: http://ntp.niehs.nih.gov/ntp/htdocs/Chem_Background/ExSumPdf/DimethylamineBorane508.pdf

External links[edit]