The synthesis of ibuprofen from 2-methylpropylbenzene isobutylbenzene and carbon dioxide involves several steps, including Friedel-Crafts alkylation, hydrolysis, and carboxylation. Here is the detailed mechanism:1. Friedel-Crafts Alkylation:In the first step, 2-methylpropylbenzene isobutylbenzene undergoes Friedel-Crafts alkylation with propionyl chloride in the presence of a Lewis acid catalyst, such as aluminum chloride AlCl3 . The catalyst activates the carbonyl group of propionyl chloride, making it more electrophilic. The benzene ring then attacks the carbonyl carbon, forming a new carbon-carbon bond and generating a cationic intermediate. The intermediate loses a proton to regenerate the aromaticity of the benzene ring, resulting in the formation of 2- 4-isobutylphenyl propanoyl chloride.2. Hydrolysis:The 2- 4-isobutylphenyl propanoyl chloride is then hydrolyzed in the presence of water and a base, such as sodium hydroxide NaOH , to form 2- 4-isobutylphenyl propionic acid. The base deprotonates the water molecule, making it a better nucleophile. The hydroxide ion attacks the carbonyl carbon, leading to the formation of a tetrahedral intermediate. The chloride ion then leaves, and the carbonyl group is reformed, resulting in the formation of the carboxylic acid.3. Carboxylation:In the final step, 2- 4-isobutylphenyl propionic acid is treated with carbon dioxide CO2 and a base, such as sodium hydroxide NaOH , to form ibuprofen. The base deprotonates the carboxylic acid, generating a carboxylate ion. The carboxylate ion then reacts with CO2, forming a new carbon-carbon bond and generating a bicarbonate intermediate. The intermediate is then protonated by water, yielding ibuprofen.In summary, the synthesis of ibuprofen from 2-methylpropylbenzene and carbon dioxide involves Friedel-Crafts alkylation, hydrolysis, and carboxylation steps. The reagents and intermediates play crucial roles in activating electrophiles, facilitating nucleophilic attacks, and generating the desired product.