The dimethylaniline or dimethylphenylamine is an organic compound that is formed by a benzene ring with an amino group substituted with two methyl groups. Its chemical formula is C8HelevenN.
It is also known as N, N-dimethylaniline, as it is a derivative of aniline in which the hydrogens of the amino group are replaced by two methyl groups. This makes it a tertiary amine.
N, N-Dimethylaniline is a pale yellow to brown oily liquid with the characteristic odor of amines. It is a basic compound and reacts with nitrous acid to form a nitroso compound. When exposed to air it turns brown.
It is used in the manufacture of colorants for paints. It is also used as an activator for polymerization catalysts and in mixtures used for image recording. In turn, it has been used in the synthesis of antibacterial or antibiotic compounds such as certain penicillin-derived cephalosporins. N, N-dimethylaniline is also a base to obtain other chemical compounds.
It is a combustible liquid and when heated to decomposition it emits toxic fumes. Acute human exposure to N, N-dimethylaniline can lead to negative effects such as headaches, dizziness, decreased oxygen in the blood and bluish discoloration of the skin, among other symptoms..
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The following figure shows the spatial structure of N, N-dimethylaniline:
- N, N-dimethylaniline
- Dimethylaniline
- Dimethylphenylamine
- N, N-dimethylbenzenamine
N, N is placed in the name to indicate that the two methyl groups (-CH3) are attached to nitrogen (N) and not to the benzene ring.
Pale yellow to brown liquid.
121.18 g / mol.
3 ºC.
194 ºC.
63 ºC (closed cup method). It is the minimum temperature at which it gives off vapors that can ignite if a flame is passed over it..
0.70 mm Hg at 25 ºC.
371 ° C. It is the minimum temperature at which it burns spontaneously at atmospheric pressure, without an external source of heat or flame..
0.9537 g / cm3 at 20 ºC.
1.5582 at 20 ºC.
In water it is very slightly soluble: 1,454 mg / L at 25 ºC.
Freely soluble in alcohol, chloroform and ether. Soluble in acetone, benzene, and oxygenated and chlorinated solvents.
Kb 11.7, which indicates the ease with which this compound accepts a hydrogen ion from water.
N, N-dimethylaniline is a basic compound. Reacts with acetic acid to give N, N-dimethylanilinium acetate.
The group -N (CH3)two of N, N-dimethylaniline is a powerful activator of aromatic substitution at the position in order to of the benzene ring.
Reacts with sodium nitrite (NaNOtwo) in the presence of hydrochloric acid (HCl) forming p-nitroso-N, N-dimethylaniline. Also with nitrous acid it generates the same nitrosated compound in position in order to.
When N, N-dimethylaniline reacts with benzenediazonium chloride, in a mildly acidic medium, an azo compound of the type Ar-N = N-Ar 'is produced, where Ar is an aromatic group. Molecules with azo groups are strongly colored compounds.
When heated to decomposition it emits highly toxic aniline vapors and nitrogen oxides NOx.
It is a combustible liquid.
It decomposes slowly in water exposed to sunlight. Does not biodegrade.
It volatilizes from wet soil and water surfaces. It does not evaporate from dry soil and moves through it. Does not accumulate in fish.
It can be absorbed through the skin. It is also rapidly absorbed by inhalation. Human exposure to N, N-dimethylaniline can decrease the oxygen content of the blood resulting in a bluish color of the skin..
Acute inhalation of this compound can lead to negative effects on the central nervous system and the circulatory system, with headaches, cyanosis and dizziness..
It can be produced in several ways:
- From aniline and methanol under pressure in the presence of acid catalysts, such as HtwoSW4. Sulfate is obtained which is converted to the base by adding sodium hydroxide.
- Passing an aniline vapor and dimethyl ether over activated aluminum oxide.
- Heating a mixture of aniline, anilinium chloride and methanol under pressure and then distilling.
Due to the property of reacting with benzenediazonium chloride to form azo compounds, N, N-dimethylaniline is used as an intermediate in the manufacture of colorants..
It is a raw material in the synthesis of the dyes of the methyl violet family.
N, N-dimethylaniline is part of a photocurable mixture that undergoes the curing reaction as a result of high sensitivity to visible or near infrared light, so that it can be used for image recording or photoresist materials..
N, N-dimethylaniline is one of the components of the mixture that cause sensitization to wavelengths, in such a way that the composition is cured with light of low energy wavelengths.
It is estimated that the role of N, N-dimethylaniline is likely to suppress the radical polymerization termination reaction caused by oxygen..
N, N-dimethylaniline is used as a catalytic hardener in certain fiberglass resins.
N, N-dimethylaniline participates in the synthesis of cephalosporins starting from penicillins.
Penicillin sulfoxides are converted to cepheme derivatives when heated in the presence of basic catalysts such as N, N-dimethylaniline.
These cephalosporins exhibit antibacterial activity against gram-positive and gram-negative organisms, as well as against penicillin-resistant staphylococci..
However, it should be noted that N, N-dimethylaniline remains in these antibiotics as an impurity..
N, N-dimethylaniline is used in the activation of olefin polymerization catalysts.
It is used together with pentafluorophenol (C6F5OH) with which it forms the ionic compound [HNPhMetwo]+[H (OC6F5)two]-. This ionic compound has one or two active protons that activate the catalyst based on a transition metal.
Additionally, in the manufacture of resins, N, N-dimethylaniline has been used as a polymerization accelerator or promoter for the formation of polyester resins. Its action generates a rapid curing of the resin.
It is used in the synthesis of other chemical compounds, for example, vanillin, and as an intermediate for pharmaceutical drugs.
It is also used as a solvent, as an alkylating agent, as a stabilizer, and to make paints and coatings..
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