Qualitative test
Carbylamine test
Tests using isocyanide are also called isocyanide tests. There is the formation of isocyanide as well as carbylamine when the solution is heated with an alcoholic solution as well as chloroform that then possess an unpleasant odor.R-NH2 + CHCl3 + 3KOH (alc.) —> R-NC + 3KCL + 3H2O
A second and tertiary amine cannot be tested with this test. Only primary amines can be tested. This can be used to show when primary amines arise from secondary amines or tertiary amines.
Liberman's nitroso reaction
Nitrous acid slowly reacts with secondary aliphatic and aromatic amines to produce yellow oily nitroso amines in the cold. When you warm conc. sulphuric acid and phenol, a yellow oily nitrosamine solution turns into green solution. Sodium hydroxide changes the colour from greenish-blue to violet when diluted with water. So, this reaction is ultimately called as Liberman’s nitroso reaction. Usually, this test is used in secondary amines.Reaction with aryl sulphonyl chloride
Sulphonamides can be synthesized by using Hinsberg's reagent, which is also known as benzene sulphonyl chloride.- Benzene sulphonyl chloride reacts with primary amines to form N-alkyl benzene sulphonamide. Since the nitrogen atom in sulphonamide has an electron-withdrawing sulphonyl group, its hydrogen is highly acidic, therefore, its solubility in alkali. But it gives an insoluble material on acidification.
- For the formation of N, N-dialkyl benzene sulphonamide, secondary amines are the ones that react with benzene sulphonamide. It is not considered as acidic because there is no presence of hydrogen atom that is attached to nitrogen atom. And hence it is insoluble in alkali.
- Benzene sulphonyl chloride does not react with tertiary amines.
Reaction with carbon disulphide
To give alkyl isothiocyanates as the final products, primary amines reacts with carbon disulphide which then helps to form dithioalkyl carbamic acids and then it decomposes with mercuric chloride on heating. Hoffmann mustard oil reaction smells like mustard oil and is widely used as a test for the presence of primary amines, hence its name.Azo dye test for amines
There is a reaction between diazonium salts and aromatic amines due to which there is the formation of azo compounds in an acidic medium known as dyes. This reaction is commonly known as coupling or diazo reaction and this test is known to be azo dye test.Oxidation with Caro’s acid or H2O2
A common test for testing aromatic amino groups. Du to the high electron density on the benzene rings of the aromatic amines, they get readily oxidized on exposure to air and even the exposure to oxidizing agents forms a complex coloured product.C6H5NH2 + K2Cr2O7 + H2SO4 —> aniline black (it is the black product formed as the end product)
To yield p-benzoquinone, however, potassium dichromate and sulphuric acid must be utilized for oxidizing aniline.
Halogenation tests
To test an aromatic amino group, this test is highly used. To give the white precipitate of 2,4,6-tribromoaniline, an aniline readily reacts with the bromine water.Solubility test
Amines are considered polar organic compounds because they have only one lone pair. Mineral acids dissolve them easily due to their basic nature. The presence of the lone pair in amines plays a key role in the basic nature of these molecules. Through this test, amines are not confirmed.The reaction given below shows the basic nature of amines.
C6H5NH2 + HCl —> C6H5NH3 + Cl-
Litmus test
Amines have the tendency to turn litmus paper in blue colour due to its basic nature. However, this test is not enough to confirm the presence of amine group. This test helps in the confirmation of the litmus test.Ethanolamine
Structure
Ethanolamine is a colorless and clear liquid with a smell akin to ammonia. Flammable at 185°F. Can attack rubber, copper, and brass. May corrode tissue. Toxic to moderate levels. During combustion, releases nitrogen oxides that are toxic.In the class of ethanolamine, ethanolamine is ethane with hydroxy substituents at C-1 and C-2, thus being a primary alcohol as well as a primary amine. As a human metabolite, a metabolite of Escherichia coli, and a metabolite of mice, it has several roles. As a primary amine, primary alcohol, and ethanolamine, it belongs to the group of primary amines. Based on ethanolamine (1+), it is a conjugate base.
Uses
- Detergents, emulsifiers, polishes, pharmaceutics, corrosion inhibitors, and chemicals are made with it.
- Cosmetics use it as a pH regulator.
Ethylenediamine
Structure
The compound with the formula C2H4(NH2)2 is ethylenediamine (abbreviated as en when it is a ligand). Despite its colorless appearance, amines have an ammonia-like smell. Ethylenediamine is widely used in chemical synthesis, generating approximately 500,000 tonnes in 1998[6]. Contact with moisture in humid air produces a corrosive, toxic and irritating mist, which can be harmful even at short exposures. A polyethylene amine is the first ethylenediamine.
Uses
- Chelating agents such as EDTA are primarily derived from ethylenediamine.
- Piperoxan, first-generation antihistamine, is synthesized from ethylenediamine.
Amphetamine
Structure
Schedule II drugs are amphetamines according to the DEA. There is a high potential for abuse of Schedule II substances, which may result in psychological dependence or physical dependence.The structure of amphetamines resembles that of adrenaline and norepinephrine. Therefore, these chemicals can produce similar biological effects, such as stimulating the central nervous system and creating a feeling of prowess and alertness. Modelling these chemicals after amphetamine, Benzedrine used to be a common name for this substance, the difference is that there are fewer -OH groups and an extra methyl on the side chain, similar to norepinephrine. Benzedrine creates a feeling of buoyancy and well-being, however, and was soon discovered to be a euphoriant.
Uses
- The drug is also used for treating obesity and narcolepsy (a sleeping disorder) in addition to treating ADHD.
- Amphetamine enhances athletic performance and mental alertness in some athletes through its psychological and physiological effects.
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