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Alicyclic Compound

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Introduction to Alicyclic Compound

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Given the Alicyclic Compounds Definition odour colour chemistry, an alicyclic compound is defined as any of a large class of organic compounds in which either three or more atoms of the carbon element are linked together in a ring. The bonds between the pairs of adjacent atoms can all be of the type designated single bonds (involving the two electrons), or a few of them may be either double or triple bonds (with either four or six electrons, respectively).


About Alicyclic Compounds

The six-membered rings, where a system of alternating single and double bonds can be envisioned, however, belong to another important class (which are aromatic compounds) and distinguished from the alicyclic compounds by a characteristically various pattern of chemical reactivity. Such alicyclic compounds, where the ring has either three or four carbon atoms, are less stable compared to the compounds having larger rings due to the angles formed by adjacent covalent bonds are smaller compared to is necessary for maximum effectiveness.

In the larger rings, all the bond angles contain the preferred value (up to 109.5°); consequently, the atoms present in the ring do not lie in one plane. The same restrictions on the angles in both double and triple bonds affect the alicyclic compound’s stability containing such bonds.


Types of Cyclic Organic Compounds:

Alicyclic Compounds

An organic compound is the one where the carbon atoms are linked to form either one or more rings. Aromatic compounds are excluded due to their special properties. Generally,  alicyclic compounds resemble analogous aliphatic compounds.

An example of an alicyclic compound is: Cyclohexane (C6H12) and so are many terpenes, like menthol.


Aromatic Compounds

A compound that contains at least one aromatic ring is defined as Aromatic compounds. The aromatic ring is a highly stable planar ring of atoms with resonance structures that consist of both alternating double and single bonds, for example, benzene. Aromatic compounds are so-called due to their special and strong characteristic odours.


Examples of Aliphatic Compounds

Some of the examples of aliphatic compounds can be given as methane (CH4, which is the simplest aliphatic compound, which is often used as fuel in Bunsen burners), LNG (Liquified Natural Gas), isotane, propane (which is used in home heating), and acetylene (flammable, explosive, which is used in welding). Also, polyethylene can be used in plastic form, but do not breathe the fumes of burning polyethylene because it is very toxic.

A few of the aliphatic compounds are cyclic in nature, but they can form unstable rings. However, their rings are not as stable as similar aromatic compounds.

Also, there are aliphatic acids that react with any of the base compounds; some examples of aliphatic acids are given as propionic acid, acetic acid (in vinegar), and butyric acid. Even vinegar can be dangerous and harmful in strong concentration.


Characteristics of Aromatic Compounds

Usually, a compound is said to be aromatic, or it has aromatic characteristics when there is a planar, fully conjugated ring having 4n+2 electrons in the conjugated system, where n is an integer.

Aromatic compounds are more special and are more stable than expected. For example, benzene vs. 1, 3, 5-hexatriene. They both contain six carbons and three double bonds, and both have all their double bonds conjugated. From these particular similarities, one might expect they have the same heat of hydrogenation, or they have the same absolute energy. However, what we find is that, significantly, benzene is more stable compared to its linear counterpart.

The other characteristic of aromatic compounds can be given as their absorption spectra. Conjugation lowers the energy that is necessary for electrons to jump from HOMO to LUMO. This process results in aromatic compounds by absorbing light in the UV spectra. Often, this characteristic is used to aid in calculating the reaction rates or identifying the unknowns.

Also, there are several nuances and cute things concerning the aromatic compounds, such as how reactions work with aromatic compounds through the nucleophilic or electrophilic substitution or how the potential for aromaticity affects acidity (think cyclopentadiene).


Aliphatic Hydrocarbons

Aliphatic hydrocarbon solvents can be described as organic compounds whose carbon atoms are linked in the open chains, either branched or straight, rather than having a benzene ring. These solvents do not contain a benzene ring, but they are the mixtures of saturated, branched-chain (Iso-paraffin), long straight chain (normal-paraffin), or cyclic paraffin.

They can be produced by the crude oil distillation with a proper boiling point range fraction, and after that, they are treated to improve their odour and colour. Also, aliphatic hydrocarbon solvents are considered aliphatic compounds, and they contain hydrogen and carbon that are joined together in branched trains, straight chains, or non-aromatic rings.

The alicyclic hydrocarbons of the type of alkene, alkane, and alkyne series are given as the aliphatic compounds, same as the fatty acids and several other compounds; thus, aliphatic compounds are used as the opposite of aromatic compounds. In addition to their use as diluents or solvents in thinners and paints, they can be widely used in degreasing, oil extraction, rubber manufacturing, and also as carriers for disinfectants and aerosols.

FAQ (Frequently Asked Questions)

1. Explain if Alicyclic Compounds are Saturated Compounds?

Answer: Alicyclic compounds need not always be saturated. The cyclic organic compounds, where generally do not possess anti aromaticity or aromaticity, are called alicyclic compounds. As it is quite clear from the name itself that it is cyclic and aliphatic. Since the aliphatic compounds may be unsaturated, thus the alicyclic compounds may also be unsaturated.

2. What are Alicyclic Compounds?

Answer: An alicyclic compound is defined as an organic compound, which is both cyclic and aliphatic. They either have one or more all-carbon rings that may be either saturated or unsaturated, but they do not hold aromatic character. Alicyclic compounds can have either one or more aliphatic side chains attached.

3. Explain if Aliphatic Hydrocarbons are Dangerous?

Answer: No, the aliphatic hydrocarbons are inert; that means they do not readily react with anything else. For this particular reason, aliphatic hydrocarbons may be considered very safe in any chemical environment.


The major “danger” associated with aliphatic hydrocarbons is that all are flammable; it means that they may easily burn if there is an ignition source (a flame, a spark, and so on) and plenty of air (oxygen) as well.

4. Give Examples of Aliphatic Hydrocarbons?

Answer: Kerosene and gasoline are examples of aliphatic hydrocarbon solvents. Common aliphatic hydrocarbon solvents that are used in coatings and paints are hexanes, mineral spirits, and heptanes.