Question

Carbonation of methylmagnesium bromide gives an organic compound. This compound is also obtained by (a) Hydrolysis of methyl formate with dilute mineral acid (b) Oxidation of methyl alcohol (c) Hydrolysis of methyl formate with dilute mineral acid (d) Hydrolysis of acetonitrile by a mineral acid

Short answer

The answer is (d), Hydrolysis of acetonitrile by a mineral acid.

Step-by-step solution

Understand the Reaction

When methylmagnesium bromide, a Grignard reagent, reacts with carbon dioxide, it forms a carboxylate salt which, upon acidification, gives acetic acid (00-CH₃).

Analyze Option (a)

Hydrolysis of methyl formate (HCOOCH₃) using a dilute mineral acid yields formic acid (HCOOH) and methanol (CH₃OH). This reaction does not produce acetic acid.

Analyze Option (b)

Oxidation of methyl alcohol (CH₃OH) first leads to the formation of formaldehyde (HCHO), and upon further oxidation, it does formic acid, not acetic acid.

Analyze Option (c)

This option appears to be miswritten since it is identical to (a). Neither are related to the production of acetic acid specifically.

Analyze Option (d)

Hydrolysis of acetonitrile (CH₃CN) by a mineral acid produces acetic acid (00-CH₃), as the nitrile group converts to a carboxylic acid group in the process.

Conclusion

Only the hydrolysis of acetonitrile by a mineral acid corresponds to the formation of the same final product as carbonation of methylmagnesium bromide, acetic acid.

Key concepts

Methylmagnesium Bromide

Methylmagnesium bromide, a popular Grignard reagent, is a compound where a magnesium atom is bonded to a methyl group and a bromine atom. It’s usually represented as CH₃MgBr. The compound is crucial in organic chemistry for forming Grignard reactions, which create carbon-carbon bonds. Grignard reagents react with a variety of electrophilic compounds, allowing for the synthesis of a wide array of organic molecules. In this specific context, when methylmagnesium bromide reacts with carbon dioxide, it undergoes a carboxylation reaction. One of the carbon dioxide’s oxygen double bonds breaks, and the Grignard reagent adds to it. This results in a carboxylic acid salt. When this salt is acidified, it turns into a carboxylic acid, here resulting in acetic acid. The cleverness in using Grignard reagents lies in their versatility for synthesizing complex molecules through simple reactions. Whether making alcohols, acids, or other functional groups, Grignard reactions remain a staple in the chemist's toolkit.

Carboxylic Acid Formation

Carboxylic acids are critical in organic chemistry due to their ability to participate in various chemical reactions. They are characterized by the presence of a carboxyl group (-COOH). In this context, the formation of acetic acid showcases a straightforward process of carboxylic acid production through the carbonation of methylmagnesium bromide. When introducing carbon dioxide to the Grignard reagent methylmagnesium bromide, a carboxylation reaction occurs. This transforms the carbon dioxide into a carboxylate ion, which subsequently forms the carboxylic acid upon acidification. This process highlights a common method in organic synthesis to create carboxylic acids. Besides being formed from reactions involving Grignard reagents, carboxylic acids can also emerge from other processes like hydrolysis. The reaction mechanisms involved ensure that carboxylic acids remain versatile intermediates in producing numerous complex molecules.

Hydrolysis of Nitriles

Hydrolysis is a chemical process in which water breaks chemical bonds, and in organic chemistry, nitriles can be transformed into carboxylic acids via hydrolysis. Hydrolosis of nitriles involves breaking the nitrogen-carbon triple bond with a water molecule. In the exercise, acetonitrile (CH₃CN), a simple nitrile, undergoes hydrolysis in the presence of a mineral acid. When hydrolyzed, the nitrile group in acetonitrile converts into a carboxylic acid group, producing acetic acid. This transformation aligns with the final product formed in the carbonation of methylmagnesium bromide. The capability of converting nitriles to carboxylic acids is not only practical but also environmentally beneficial as it allows for the creation of essential organic acids without extensive resources. This method provides a robust route for synthesizing necessary compounds in both laboratory settings and industrial production.