Dimethylaniline

This article is about N,N-dimethylaniline. For other constitutional isomers, see xylidine.

N,N-Dimethylaniline
IUPAC name N,N-Dimethylaniline
Other names DMA
Identifiers
CAS number	121-69-7 Y
PubChem	949
ChemSpider	924 Y
KEGG	C02846 Y
ChEBI	CHEBI:16269 Y
ChEMBL	CHEMBL371654 Y
Jmol-3D images	Image 1
SMILES CN(C)c1ccccc1
InChI InChI=1S/C8H11N/c1-9(2)8-6-4-3-5-7-8/h3-7H,1-2H3 Y Key: JLTDJTHDQAWBAV-UHFFFAOYSA-N Y
Properties
Molecular formula	C8H11N
Molar mass	121.19 g/mol
Appearance	colourless liquid
Density	0.956 g/mL
Melting point	2 °C
Boiling point	194 °C
Hazards
MSDS	External MSDS
Flash point	63 °C
Y (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

N,N-Dimethylaniline (DMA) is an organic chemical compound, a substituted derivative of aniline. It consists of a tertiary amine, featuring dimethylamino group attached to a phenyl group. This oily liquid is colourless when pure, but commercial samples are often yellow. It is an important precursor to dyes such as Crystal violet.

Preparation and reactions

DMA was first reported in 1850 by A. W. Hofmann, who prepared it by heating aniline and iodomethane:^{[citation needed]}

C₆H₅NH₂ + 2 CH₃I → C₆H₅N(CH₃)₂ + 2 HI

DMA is produced industrially by alkylation of aniline with methanol in the presence of an acid catalyst:^[1]

C₆H₅NH₂ + 2 CH₃OH → C₆H₅N(CH₃)₂ + 2 H₂O

Similarly, it is also prepared using dimethyl ether as the methylating agent.

Dimethylaniline undergoes many of the reactions expected for an aniline, being weakly basic and reactive toward electrophiles. For example, it is nitrated to produce tetryl, a derivative with four nitro groups which was once used as explosive. It is lithiated with butyllithium. Methylating agents attack the amine to give the quaternary ammonium salt:^[2]

C₆H₅N(CH₃)₂ + (CH₃O)₂SO₂ → C₆H₅N(CH₃)₃CH₃OSO₃

Applications

DMA is a key precursor to commercially important triarylmethane dyes such as Malachite green and Crystal violet.^[3] DMA serves as a promoter in the curing of polyester and vinyl ester resins.^[4] DMA is also used as a precursor to other organic compounds.

References

1. ^ Thomas Kahl, Kai-Wilfrid Schröder, F. R. Lawrence, W. J. Marshall, Hartmut Höke, Rudolf Jäckh "Aniline" in Ullmann's Encyclopedia of Industrial Chemistry 2007; John Wiley & Sons: New York.doi:10.1002/14356007.a02_303
2. ^ J. Jacques and A. Marquet (1988), "Selective α-Bromination of an Aralkyl Ketone with Phenyltrimethylammonium Tribromide: 2-Bromoacetyl-6-methoxynaphthalene and 2,2-Dibromoacetyl-6-Methoxynaphthalene", Org. Synth., http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=CV6P0175 ; Coll. Vol. 6: 175 
3. ^ Thomas Gessner and Udo Mayer "Triarylmethane and Diarylmethane Dyes" in Ullmann's Encyclopedia of Industrial Chemistry 2002, Wiley-VCH, Weinheim.doi:10.1002/14356007.a27_179
4. ^ General Info on DMA (N,N-Dimethylaniline), Composites Australia