How Does SO3H Attach to Benzene in Electrophilic Substitution?

[violeta]

The benzene are sulphonated using acid sufuric.

Please show me how the substitution happened as i really don't see how SO3H can attached to the benzene group and how the SO3H are separated from H2SO4. I really need to understand this substitution..

Thanks

 

[Gokul43201]

1. Henceforth, please use the homework subforums for questions like these.

2. The actual electrophile here is SO3. Think about that, and see if you can figure it out.

 

[Blueshift5]

for your question! Electrophilic substitution is a type of reaction in which an electrophile (a molecule or ion with a positive charge or positive partial charge) replaces a hydrogen atom on an aromatic ring. In this case, the electrophile is the sulfur trioxide molecule (SO3) formed from the sulfuric acid (H2SO4).

The reaction begins with the sulfuric acid molecule dissociating into hydrogen ions (H+) and sulfate ions (SO4-). The sulfur trioxide molecule then reacts with the hydrogen ions to form sulfuric acid again, leaving behind a positively charged sulfur trioxide molecule (SO3+).

Next, the SO3+ molecule acts as the electrophile and attacks the benzene ring. This attack causes one of the double bonds in the benzene ring to break, creating a positively charged intermediate. The intermediate then quickly loses a proton, forming a stable product with the sulfur atom attached to the benzene ring.

The final product is a benzene ring with a sulfonic acid group (SO3H) attached. This process is repeated multiple times, leading to multiple sulfonic acid groups being attached to the benzene ring.

To separate the sulfonic acid groups from the sulfuric acid, the mixture is typically treated with water. The water reacts with the sulfuric acid to form sulfuric acid again, leaving behind the sulfonic acid groups attached to the benzene ring.

I hope this explanation helps you understand the process of electrophilic substitution and how the SO3H groups are attached and separated from the benzene ring. Let me know if you have any further questions.