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Amine is a chemical compound obtained from ammonia (NH3), often called a derivative of ammonia. These derivatives form weak bases as defined in organic chemistry. The amines in organ nitrogen compounds contain nitrogen atoms in a lone pair. The alkyl group substitutes the amines present in hydrogen atoms. The nitrogen compound derivative contains alkaloids present in specific plant systems.
Some examples of amines are aniline, trimethylamine, amino acids, and biogenic amines. Also, inorganic ammonia compounds like ammonium chloride (NH4Cl) are called amines. Let us briefly discuss the nitrogen compound, its properties, and types of amines.
Classification of amines
An amine is a derivative compound of ammonia. Its performance is based on how the ammonia molecules replace the hydrogen atoms present in the compound. The classification is as follows-
Primary amine
Secondary amine
Tertiary amine
Cyclic amine
Primary amine – Primary amines are obtained when an alkyl or aromatic group replaces any one hydrogen out of the three hydrogen atoms of ammonia. Some names of primary alkylamines are amino acids, methylamine, and buffering agent tris. Examples of primary amine are Methylamine CH3NH2, Aniline C6H5NH2.
Secondary amine – consists of two organic substituent, namely alkyl or aryl. Both the organic compounds are bound with nitrogen and one hydrogen. For instance, aromatic amine and dimethylamine are comparable with diphenylamine.
Example of Secondary type of amine – Dimethylamine (CH3)2NH, Diphenylamine (C6H5)2NH.
Tertiary amine – When three nitrogen compounds contain three substituent, it is known as a tertiary type of amine. Although, the substituent which link with nitrogen determines the fourth sub-category of tertiary amines. Trimethylamine C3H9N and Ethylenediamine tetra-acetic acid (EDTA) are examples of tertiary amines.
Cyclic amine – A cyclic amine type is either a secondary or tertiary type of amine of an aromatic ring structure. The cyclic amines examples are a 3-membered ring aziridine (C2H5N) and 6-membered ring piperidine (C5H11N). Meanwhile, the N-methylpiperidine (C6H13N) is an example of cyclic tertiary amine.
Properties of amines
Amines are liquid at room temperature and contain 3-4 carbons. On the other hand, primary amines at higher temperatures are solid.
The lower aliphatic amines can obtain water molecule hydrogen bonds resulting in a water-soluble compound.
Lower aliphatic amines are gasses with a fishy odor.
When aniline and arylamines are stored in an open place, they develop color, otherwise, they are colorless.
An increase in the size of hydrophobic alkyl leads to a reduction in amine molar weight, decreasing water solubility.
Generally, the soil remains insoluble because of the lower amine nitrogen compound. Organic solvents like benzene, ether, and ethanol dissolve the nitrogen compound in one go.
Primary and secondary types of amines also participate in bonding nitrogen and hydrogen of other atoms in molecular interaction.
Boiling point of amine is usually 48.60C > 37.00C > 3.5 0C.
Aromatic amines are less likely to use acids following their lone pair of electrons in a nitrogen compound. Thus, they are less basic than aliphatic amines.
Following the presence of two hydrogen atoms at the same place, an intermolecular interaction is more likely to be eminent with the primary amines than that of the second amines.
Due to the absence of hydrogen atoms, the tertiary type of amines cannot have an intermolecular association for bonding.
Lastly, an increase in molecular mass leads to an increase in the boiling point of amine. However, it depends on intermolecular hydrogen bonding.
How to prepare primary types of amines?
Primary amines use a large amount of ammonia derivatives. Subsequently, haloalkanes form a reaction with amines to provide a composite alkyl substitute by releasing halogen acid. When the halogenoalkanes heats with primary amines, it forms a complex series of reactions. The reaction series consists of secondary and tertiary amines and their quaternary ammonium salts.
The steps that lead to the preparation of primary amine are:
The reaction of amines with halogenoalkanes
Reducing nitriles
Gabriel-phthalimide synthesis
The process must be used efficiently to obtain an accurate primary amine reaction.
Conclusion
Amines are derivatives of ammonia compounds that perform various metabolic and physiological functions in living organisms. Amines are commonly found in primary, secondary, tertiary, and cyclic types. All these classified amines react with certain compounds at room or high temperatures. Amines note the molecular interaction in a specific structure while bonding in the presence of hydrogen atoms. Furthermore, all the amine types are set according to their preference at the boiling point, i.e. primary>secondary>tertiary. The process continues until the ammonia replaces the hydrogen atoms while forming a reaction.
