Dimethylaniline
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:
DMA is produced industrially by alkylation of aniline with methanol in the presence of an acid catalyst:
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:
Xylidine
Xylidine can refer to any of the six isomers of xylene amine, or any mixture of them. All isomers are toxic.
The chemical formula of xylidines is C8H11N, or (CH3)2C6H3NH2. They are stable and combustible and react with strong oxidizing agents. They may be light sensitive. The CAS number for the isomer mixture is 1300-73-8. They are typically yellow liquids (except 3,4-xylidine which is solid) that darken when exposed to air and light. They are miscible with ethanol and diethyl ether and slightly soluble in water.
Xylidines are produced as byproducts of fractional distillation of coal tar.
Their risk and safety phrases are R20 R22 R36 R37 R38.
Xylidines are chiefly used in production of pigments and dyestuffs, and also various antioxidants, agrochemicals, pharmaceuticals, and many other organic chemicals.
Xylidines are also used as a component of the Tonka rocket fuel.
2,3-xylidine
2,3-xylidine, also called o-xylidine, 2,3-dimethylaniline, 2,3-xylylamine, or 2,3-dimethylphenylamine, is a liquid with melting point 2.5 °C and boiling point 222 °C, and flash point at 96 °C. Its CAS number is 87-59-2 and its SMILES structure is Nc1cccc(C)c1C. It is used in production of mefenamic acid, dyes, and pesticides.
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