Question

Write a balanced chemical equation using condensed structural formulas for \((\mathbf{a})\) the formation of butyl propionate from the appropriate acid and alcohol, \((\mathbf{b})\) the saponification (base hydrolysis) of methyl benzoate.

Short answer

(a) Formation of butyl propionate: \(CH_3CH_2COOH + CH_3CH_2CH_2CH_2OH \rightarrow CH_3CH_2CH_2CH_2O_2CCH_2CH_2CH_3 + H_2O\) (b) Saponification of methyl benzoate: \(C_6H_5COOCH_3 + NaOH \rightarrow C_6H_5COONa + CH_3OH\)

Step-by-step solution

(a) Identifying the reactants for butyl propionate formation

To form butyl propionate, we need to combine an appropriate acid and alcohol. Butyl propionate has the condensed structural formula \(CH_3CH_2CH_2CH_2O_2CCH_2CH_2CH_3\). This ester is derived from propanoic acid (propionic acid) \((CH_3CH_2COOH)\) and butanol (butyl alcohol) \((CH_3CH_2CH_2CH_2OH)\).

(a) Writing the balanced chemical equation for butyl propionate formation

Now that we have identified the reactants, we can write the balanced chemical equation for the formation of butyl propionate. Propanoic Acid + Butanol → Butyl Propionate + Water In condensed structural formulas: \(CH_3CH_2COOH + CH_3CH_2CH_2CH_2OH \rightarrow CH_3CH_2CH_2CH_2O_2CCH_2CH_2CH_3 + H_2O\)

(b) Writing the balanced chemical equation for saponification of methyl benzoate

For the saponification (base hydrolysis) reaction of methyl benzoate, we need to carry out the hydrolysis reaction in the presence of a strong base such as sodium hydroxide (NaOH). Methyl benzoate has the condensed structural formula \(C_6H_5COOCH_3\). Methyl Benzoate + Sodium Hydroxide → Sodium Benzoate + Methanol In condensed structural formulas: \(C_6H_5COOCH_3 + NaOH \rightarrow C_6H_5COONa + CH_3OH\)

Key concepts

Balanced Chemical Equation

A balanced chemical equation is essential in representing a chemical reaction accurately. It ensures that the number of atoms for each element is the same on both sides of the equation, maintaining the law of conservation of mass. This concept is foundational for chemistry because it helps understand the stoichiometry of a reaction, or the quantitative relationship between reactants and products.
To achieve a balanced equation:

• Identify all reactants and products in the reaction.
• Count the number of atoms for each element in both reactants and products.
• Add coefficients to make the number of atoms for each element equal on both sides.
• Re-check to confirm all atoms balance and that ratios reflect the actual reaction.

In the example given, when forming butyl propionate or conducting saponification of methyl benzoate, balancing the equation is crucial to accurately predicting the amounts of each substance involved.

Esterification

Esterification is a chemical reaction process where an alcohol reacts with an acid, resulting in the formation of an ester and water. This chemical reaction is typically catalyzed by an acid, such as sulfuric acid, to increase its rate. Esterification is an important reaction in organic chemistry due to its role in forming esters, which are compounds often found in fragrances and flavorings.
In the context of creating butyl propionate:

• Propanoic acid (\(CH_3CH_2COOH\)
• The hydrogen from the carboxylic acid group of propanoic acid combines with the hydroxyl group of butanol to form water.
• The oxygen from butanol bonds with the acyl group of the acid to form butyl propionate.

The general reaction can be represented as:\[ \text{R'OH + RCOOH} \rightarrow \text{RCOOR' + H}_2\text{O} \]

Saponification

Saponification is the process of hydrolyzing an ester in the presence of a base to form an alcohol and a salt of the acid. This reaction is famously known for its application in soap making, where triglycerides react with sodium hydroxide to produce glycerol and soap.
With regard to the saponification of methyl benzoate:

• Methyl benzoate (\(C_6H_5COOCH_3\)
• The ester is hydrolyzed into sodium benzoate (\(C_6H_5COONa\)
• This involves the base breaking the ester bond, leading to the formation of the carboxylate ion which is then neutralized by the sodium ion to form a salt.

Understanding saponification is crucial for various industrial applications, especially in the production of soaps and detergents.

Propanoic Acid

Propanoic acid, also known as propionic acid, is a type of carboxylic acid with the chemical formula \(CH_3CH_2COOH\). It features a three-carbon chain and is categorized under short-chain fatty acids.It has a sharp, pungent smell, reminiscent of sour milk.
This acid has several applications, including:

• As an artificial flavoring agent in food.
• As a preservative to inhibit mold and bacterial growth in food products, especially in baked goods.
• As a reactant in the esterification process to create various esters such as butyl propionate.

The role of propanoic acid in forming esters makes it essential in organic synthesis, contributing to the formation of diverse chemical products.

Methyl Benzoate

Methyl benzoate is an aromatic ester with the chemical formula \(C_6H_5COOCH_3\). It is produced from the reaction of methanol with benzoic acid. The compound is prevalent for its distinct pleasant aroma, often described as sweet and floral.
Methyl benzoate finds uses in:

• The perfume and fragrance industry, where it is appreciated for its aromatic qualities.
• The flavoring industry to impart floral and fruity notes to various products.
• Chemical synthesis, serving as a starting material or intermediate in the production of other aromatic compounds.

In chemical reactions, such as saponification, methyl benzoate can be hydrolyzed, transforming its chemical structure and offering utility in various chemical processes.