Question

Draw the condensed structural formula of the ester formed when each of the following reacts with methyl alcohol: a. acetic acid b. butyric acid c. benzoic acid

Short answer

(a) CH₃COOCH₃(b) C₃H₇COOCH₃(c) C₆H₅COOCH₃

Step-by-step solution

Write the Reactants

For each reaction, write the reactants involved. Remember that the general reaction for forming an ester is an acid reacting with an alcohol.(a) Acetic Acid (CH₃COOH) + Methyl Alcohol (CH₃OH)(b) Butyric Acid (C₃H₇COOH) + Methyl Alcohol (CH₃OH)(c) Benzoic Acid (C₆H₅COOH) + Methyl Alcohol (CH₃OH)

Combine the Reactants to Form Ester and Water

The general formula for esterification is:Acid + Alcohol → Ester + Water.So for each reaction, combine the reactants to form the products.

Write the Condensed Structural Formulas

Write the condensed structural formulas for the esters formed.(a) Acetic Acid + Methyl Alcohol → Methyl Acetate (CH₃COOCH₃)(b) Butyric Acid + Methyl Alcohol → Methyl Butyrate (C₃H₇COOCH₃)(c) Benzoic Acid + Methyl Alcohol → Methyl Benzoate (C₆H₅COOCH₃)

Key concepts

Acetic Acid

Acetic acid, also known as ethanoic acid, is a simple carboxylic acid with the formula CH₃COOH. It has a distinct sour taste and is the main component of vinegar. In esterification reactions, acetic acid often reacts with alcohols to form esters, compounds with pleasant, often fruity odors. When acetic acid reacts with methyl alcohol (methanol), the ester formed is methyl acetate (CH₃COOCH₃).
In this reaction:
- The carboxyl group (COOH) of the acetic acid reacts with the hydroxyl group (OH) of the methyl alcohol.
- This results in the release of water (H₂O) and the formation of the ester, methyl acetate.

Butyric Acid

Butyric acid, also called butanoic acid, has the chemical formula C₃H₇COOH. It is known for its strong smell, often compared to rancid butter. Like acetic acid, butyric acid participates in esterification reactions with alcohols to form esters.
When butyric acid reacts with methyl alcohol, the resultant ester is methyl butyrate (C₃H₇COOCH₃).
In this reaction:

• The carboxyl group (COOH) of the butyric acid interacts with the hydroxyl group (OH) of the methyl alcohol.
• This leads to the formation of water (H₂O) and the ester, methyl butyrate.

Benzoic Acid

Benzoic acid, with the formula C₆H₅COOH, is a common carboxylic acid that contains a benzene ring. It is widely used as a food preservative and in the manufacture of various chemicals. When benzoic acid reacts with methyl alcohol, it forms methyl benzoate (C₆H₅COOCH₃), an ester with a pleasant aroma often used in perfumery.
In this reaction:

• The carboxyl group (COOH) of the benzoic acid reacts with the hydroxyl group (OH) of the methyl alcohol.
• The reaction releases water (H₂O) and forms the ester, methyl benzoate.

Condensed Structural Formula

The condensed structural formula is a way of representing molecules in a simplified format. Instead of drawing out all the bonds, condensed formulas write out the molecular formula in a linear sequence.
For example:

• Acetic acid (CH₃COOH) reacts with methyl alcohol (CH₃OH) to form methyl acetate (CH₃COOCH₃).
• Butyric acid (C₃H₇COOH) reacts with methyl alcohol (CH₃OH) to form methyl butyrate (C₃H₇COOCH₃).
• Benzoic acid (C₆H₅COOH) reacts with methyl alcohol (CH₃OH) to form methyl benzoate (C₆H₅COOCH₃).

The condensed structural formula helps in quickly understanding the structure and composition of the molecule without the need for detailed structural drawings.

Methyl Alcohol

Methyl alcohol, commonly known as methanol, has the chemical formula CH₃OH. It is the simplest alcohol and is characterized by its simplicity and high reactivity in chemical reactions, particularly esterification.
In each esterification reaction:

• One molecule of methanol donates its hydroxyl group (OH).
• The carboxylic acid (like acetic, butyric, or benzoic acid) provides its carboxyl group (COOH).
• The result is the formation of an ester (such as methyl acetate, methyl butyrate, or methyl benzoate) and water (H₂O).

Methanol is highly versatile and is used in a wide range of chemical reactions beyond esterification as well.