Phenyl Group – Structure, Properties, and Uses

A phenyl group is generated whenever an atom of hydrogen detaches from the benzene ring. The sign Ph is sometimes used to denote compounds. Ar represents any functional group, including aromatic and aryl groups.

This is closely related to benzene. It can be described as a benzene ring without hydrogen, which can be replaced as a functional group by other elements or compounds. This group has six carbon atoms in a hexagonal planar structure, 5 of which are attached to hydrogen atoms.

When it comes to explaining what it is, there wouldn’t be a better definition than this one- a cyclic group of atoms with the formula C₆H₅. The group is closely related to a benzene ring in organic chemistry that does not contain any hydrogen atoms and can be replaced by any other functional group or element. 

Phenyl Structure– C6H5 

Five out of its six carbon atoms are attached to the individual hydrogen atoms in a hexagonal planar ring. The remaining ones are attached to substituent groups. This is aromatic despite having alternate double and single bonds. It also has the same bond length between carbon atoms. 

Name for the moiety of an organic molecule obtained by removing a hydrogen atom (-C₆H₅ ) from a benzene ring, used when the benzene ring is attached to a chain of 6 or more carbon atoms. 

Here R is any alkane group.

As a Compound

A compound in which a chain of carbon atoms is attached to this group is called an arena. Arenes are named using two different methods, depending on the length and complexity of the carbon atom chain. If the chain of carbon atoms contains six or fewer carbon atoms, the arena is called a benzene ring with the corresponding alkyl group.

For example, a benzene ring connected in a chain of two carbon atoms is called ethylbenzene. However, when the carbon chain is longer than six carbons or very complex, arenes are referred to as the groups attached to an alkane chain. 

Eight carbon atoms make up the chain of the chemical 3-phenylacetate, with the third carbon atom joined to the benzene ring. Whatever the length of the carbon chain. Phenylalanine is a chemical compound with two or more benzene rings. Many naturally occurring and artificially created compounds have these groups as crucial structural components.

It is a crucial component in the molecular framework of numerous medications, pesticides, dyes, polymers, fragrances, and food flavors. Many people mistake phenol for phenyl. It has no connected oxygen atoms, whereas phenol is made up of one oxygen atom. 

It is an unstable compound because the benzene ring does not include a hydrogen atom. These groups are extremely reactive substances. With the chemical formula C₆H₅ OH, phenol is the most straightforward aromatic alcohol and a stable substance. Its chemical structure is stable, and it is significantly less reactive.

The benzene ring, commonly known as this group, is a chemical compound related to benzene. Five of the six carbon atoms that make up these are connected to different hydrogen atoms to form one hexagonal planar ring. The unused carbon is used as a replacement.

Representative phenyl group-containing compounds 

• A common medication called atorvastatin (Lipitor) has these two groups and one p-fluorophenyl group. It assists those with hypercholesterolemia in lowering their cholesterol levels.
• Another popular drug, fexofenadine (Allegra, Telfast), has p-phenylene and diphenyl methyl C₆H₄ groups. Allergies are treated with antihistamines.
• A typical amino acid is known as phenylalanine. It is beneficial as a supplementary dietary supplement in meals and beverages due to its purported analgesic and depressive benefits.
• These two groups create biphenyl. The two circles are not always parallel. Specifically, when combined with diphenyl ethers, biphenyl acts like a heat transfer medium.
• Solvent: chlorobenzene, also known as phenyl chloride. It is an intermediary in manufacturing basic materials like rubber, dyes, and herbicides.

Synthesis of Phenyl Groups

• Some chemicals which serve as sources of phenyl anions or phenyl cations are frequently used to introduce them. Phenyl lithium(C₆H₅ Li) and phenyl magnesium bromide are examples of common reagents (C6H5MgBr). Benzene reacts with electrophiles to form its derivatives.

C₆H₆  + E+ → C₆H₅ E + H+ 

             where E+ (“electrophile”) = Cl+, NO2+, SO3. Electrophilic aromatic compounds are what are produced in these reactions.

Properties of Phenyl Group C₆H₅

Physical Properties of C₆H₅

• This functional group has a phenyl-like odor. 
• They have a white crystalline solid appearance. 
• C₆H₅ structure has one covalently-bonded unit.
• C₆H₅ structure ph has a heavy atom count of 6.
• C₆H₅ structure has a complexity of 27.
•  It compounds are derived, at least conceptually, from benzene (C₆H₆),  often from a production engineering point of view. These groups are insoluble in water.

Chemical Properties of Phenyl functional group

• One of the group as a phenol reacts with a bromine solution to form a Bromo-substituted phenol and hydrogen bromide. The chemical formula is shown below.

           2C₆H₅OH + 6Br₂ → 2C₆H₂Br₂OH + 6HBr

• This group as a phenol reacts with a bromine solution to form a Bromo-substituted phenol molecule and a hydrogen bromide molecule. The chemical formula found is illustrated below.
• At room temperature, this group has a 1.248 g/mol density.
• The molecular mass of the C₆H₅ structure is approximately 77.106 g/mol.
• The boiling point is found to be 232.2±7.0 °C at 70mmHg.
• The melting point is found to be -30°C.
• Its nature is hydrophobic for this group. It doesn’t get reduced or oxidized. As with other aromatic compounds, these groups are more stable than similar bonds in aliphatic or non-aromatic groups. The distinctive qualities of those aromatic molecular orbitals are responsible for this improved stability.
• This group’s carbon atoms are connected by a bond that is around 1.4 long.
• This group of protons in 1H NMR spectroscopy typically shows a chemical shift of about 7.27 ppm. Such chemical shifts can change with substituents and are driven by aromatic ring currents. 

Nomenclature of C₆H₅ Phenyl Functional Group

• This group can be typically represented by the symbol ‘Ph’ or the archaic Φ and is synonymous with C₆H₅ –. The name ‘benzene’ is sometimes used. These groups are commonly linked to other kinds of atoms or groups. For instance, the carbon core of triphenylmethane (Ph3CH) contains These three groups bonded to it. The name ‘phenyl’ does not accurately describe most of these compounds. For instance, the chloro derivative-C₆H₅ Cl is also known as phenyl chloride and is also referred to as chlorobenzene. Lone these groups, such as phenyl anions (C₆H₅ ), phenyl cations (C₆H₅ +), and phenyl radicals (C₆H₅ ), are occasionally seen.

• Ph and phenyl represent C6H–, but their derivatives are described by using the phenyl terminologies. For instance, C₆H₄ NO2– is nitrophenyl, and C₆F₅ – is pentafluorophenyl. Mono-substituted groups participate in electrophilic reactions, although the products follow the arene substitution pattern. Therefore, a substituted compound has three kinds of isomers: ortho (1,2-disubstituted), meta (1,3-disubstituted), and para (1,4-disubstituted).
• For example, a disubstituted phenyl compound can be 1,2,3-trisubstituted or 1,3,5-trisubstituted. A high degree of substitution, represented by the pentafluorophenyl group, exists and is named according to the IUPAC nomenclature.

Uses of Phenyl functional group 

• These groups are present in various organic compounds in synthetic and natural items. The most common natural product is the amino acid phenylalanine.
• Polymer polystyrene is made from phenyl-containing monomers, and its properties are because of the rigidity and hydrophobia of those groups. 
• The most important product of the petrochemical industries is BTX, consisting of benzene and xylene, which form the building rocks of these compounds. 
• Drugs and contaminants contain these rings. Phenol (C₆H₅ OH) is the simplest phenyl-included compound. 
• The resonance stability of certain phenols is often said to make them stronger acids than aliphatic alcohols(pKa = 10 vs. 16-18). However, the main factor is that it is more electronegative of the sp2 α-carbons of phenol compared to the sp3 α-carbons of aliphatic alcohols. 
• It is used to eliminate odors and promote hygiene. 
•  It is used as a disinfectant in certain social places such as schools, hospitals, malls, and companies.
•  It has pharmaceutical properties; hence, it is used as an antioxidant, analgesic, choleretic, etc.

Key Points to Remember

• This group is related to benzene and is described as a benzene ring without hydrogen.
• The most common natural product of this group is phenylalanine.
• These groups are commonly introduced using reagents as a source of phenyl anions or phenyl cations.

Frequently asked questions

1. Do phenyl groups undergo oxidation and reduction reactions?

Answer: These groups resist both reduction and oxidation reactions. These groups have greater stability than other aliphatic groups. The increased stabilities are due to the certain properties of aromatic-type molecular orbitals.

2.  How many carbon atoms are present in the phenyl group?

Answer: These groups’ nature is more or less related to benzene. This group has six carbon atoms joined together to produce a hexagonal planar ring, of which five are attached to each hydrogen atom. The rest of the carbon atoms will be used as a substitute.

3. What is the purpose of phenyl?

Answer: It is a powerful deodorant and disinfectant and is widely used for sanitary purposes in hospitals, nursing homes, sewers, toilets, restrooms, and barns.

4. Why is it called a phenyl group?

Answer: This group is named after the Greek word phaino, which means “shining.” The name derives from the fact that phenyls were first isolated from gases used in lamps.

5. What is phenyl used for?

Answer: It is commonly used in the production of plastics such as polystyrene. However, it is also used in the synthesis of drugs such as analgesics and biological molecules such as certain amino acids.