Structure and Uses of Phenols

Phenol is an aromatic compound. The chemical formulation of this organic compound is C₆H₆O. Phenol is likewise referred to as Carbolic acid.

It includes a hydroxyl group and a phenyl group connected to every other. It significantly dissolves in water. Earlier it turned into used as carbolic soap. It is mildly acidic and is corrosive to the respiration tract, eyes, and skin. Phenol is a crystalline solid white in colour and needs to be dealt with with care as it is able to reason chemical burns. Friedlieb Ferdinand Runge found Phenol withinside the year 1834.

It turned into extracted from coal tar. It is likewise referred to as phenolic acid. If a compound is such as a 6-membered aromatic ring and is bonded to a hydroxyl group directly, then it is able to be known as phenol.

Similar to alcohols, phenols have hydroxyl groups that could participate in intermolecular hydrogen bonding; in fact, phenols tend to form stronger hydrogen bonds than alcohols. (See chemical bonding: Intermolecular forces for extra data about hydrogen bonding.) Hydrogen bonding outcomes in higher melting factors and plenty higher boiling points for phenols than for hydrocarbons with similar molecular weights.

The potential of phenols to form strong hydrogen bonds additionally enhances their solubility in water. Phenol dissolves to provide a 9. 3 per cent solution in water, as compared with a 3.6 per cent solution for cyclohexanol in water. The association between water and phenol is surprisingly strong; while crystalline phenol is left out in a humid environment, it picks up sufficient water from the air to form liquid droplets.

 

Some of the chemical properties of the phenols are listed below:

The acidity of Phenols:

In order to form the corresponding phenoxide, phenols react with active metals which include sodium, potassium, etc. The acidic nature of the phenol is indicated via way of means of a majority of these reactions. The carbon that has SP2 hybridization is connected to the benzene ring and is likewise attached immediately to the hydroxyl group which acts as an electron-withdrawing group. Hence, it allows in reducing the electron density of the oxygen.

Hydrogen Bonding:

In carbon tetrachloride and alkyne solvents, there’s a large variety of Lewis bases like pyridine, diethyl ether, and diethyl sulfide that form a hydrogen bond with the phenol. Phenol is compatible with the C/E quantitative relation of the EWC model because it is classed as hard acid wherever Ea = 2.27 and CA = 1.07. The CB plot is employed for illustration of the relative acceptor strength of phenol towards a series of bases versus different Lewis acids

Phenoxide Anion:

The phenoxide anion is one of the strong nucleophiles in which its nucleophilicity e is corresponding to one of the carbanions or tertiary amines. It acts as an important nucleophile that reacts at each of its carbon and oxygen sites. Generally, while the oxygen attacks the phenoxide anions, it is are kinetically favoured while the carbon attacks the phenoxide anion, it is thermodynamically preferred. When the reaction rate reaches the diffusion control, a mixture of oxygen or carbon attack outcomes in a lack of selectivity.

Chirality of Phenols:

Phenols are visible to be exhibiting chirality inside their molecules for instance catechin. This chirality arises because of the absence of planar and axial symmetry withinside the phenol molecules.

Structure Of Phenols

An sp2 hybridised carbon atom is attached to the –OH group in phenols.

In phenol, the C-O bond is shorter than in methanol.

This is because of :

(i) The presence of a partial double bond due to the conjugation of unshared electron pairs of oxygen with * electrons of an aromatic ring

(ii) the hybridised state of carbon bonded to oxygen.

It has the structural formula C6H5OH and is sometimes called carbolic acid or benzenol. It has the following structure:

Uses of Phenols

Various industries use phenol for various purposes. Below is a complete list of phenol’s uses:

1. Phenol is the most usually used disinfectant since historical times. It has been given excellent antiseptic properties too. It changed into one of the most common chemical compounds used to clean household materials, particularly washrooms and ground tiles.
2. Phenol is proven to be a powerful anti-bacterial, anti-fungi, and anti-viral agent. A lot of research had been performed to discover the mechanism of action at the back of those properties. It has been hypothesized through a few research that it hinders the protein and RNA synthesis in microorganisms, thereby main to their death. Besides, some research declares that it damages the cytoplasmic membranes of the microorganisms.
3. Phenol, even though in very minor quantity, is likewise used withinside the manufacturing of mouthwashes for effective cleaning of the mouth and elimination of mouth bacteria.
4. Phenol is likewise sometimes used as an oral analgesic and slight anaesthetic. This is due to the numbing sensation it gives because of its astringent properties since it is an alcohol. However, precautions have to be taken at the same time as using it orally due to the fact the concentrated solution of phenol may be toxic to human pores and skin and might motive harm to the mucosal membrane.

Conclusion

Phenol is any of a family of natural compounds characterised via way of means of a hydroxyl (―OH) group connected to a carbon atom this is a part of an aromatic ring. Besides serving because the generic call for the entire family, the term phenol is likewise the particular name for its most effective member, monohydroxybenzene (C6H5OH), additionally called benzenol or carbolic acid. Phenols are just like alcohols however form stronger hydrogen bonds. Thus, they may be greater soluble in water than are alcohols and have higher boiling points. Phenols occur both as colourless liquids or white solids at room temperature and are perhaps highly poisonous and caustic.

FAQs

Is phenol acidic or basic?

Phenol can be taken into consideration as a vulnerable acid. It is in equilibrium with the phenolate anion C6H5O− (additionally referred to as phenoxide) in aqueous solutions which are in the pH range 5-6. One purpose why phenol is more acidic than aliphatic compounds is that it consists of an OH group and the aromatic ring resonance stabilizes the phenoxide anion.

What is the pH of phenol?

The pH of an average dilute solution of phenol in water is possible to be around 5 - 6 (depending on its concentration). That means that a totally dilute solution isn't always certainly acidic sufficient to show litmus paper absolutely red.