Problem 67 - Chemistry and Chemical Reactivity

Question

What is the structure of the product from the reaction of butanoic acid and methylamine? To what class of compounds does this belong? Write a balanced chemical equation for the reaction.

Step-by-Step Solution

Answer

The product is N-methylbutanamide, an amide. Equation: \( C_3H_7COOH + CH_3NH_2 \rightarrow C_3H_7CONHCH_3 + H_2O \).

Step 1: Identify the Reactants

The reactants in this chemical reaction are butanoic acid and methylamine. Butanoic acid is a carboxylic acid with the chemical formula \( C_3H_7COOH \). Methylamine is an amine with the formula \( CH_3NH_2 \).

Step 2: Describe the Reaction Type

The reaction between a carboxylic acid and an amine typically forms an amide. In this case, when butanoic acid reacts with methylamine, the product is an amide.

Step 3: Write the Structural Formula of the Product

The reaction will lose a molecule of water \( H_2O \) and form an amide linkage. The structure can be represented as \( C_3H_7CONHCH_3 \), which is N-methylbutanamide.

Step 4: Classify the Compound

The product, N-methylbutanamide, belongs to the class of compounds known as amides. Amides are characterized by the presence of a carbonyl group (C=O) bonded to a nitrogen atom.

Step 5: Write the Balanced Chemical Equation

The balanced chemical equation for this reaction is:\[ C_3H_7COOH + CH_3NH_2 \rightarrow C_3H_7CONHCH_3 + H_2O \]

Key Concepts

Carboxylic Acids

Carboxylic acids are organic compounds that contain a carboxyl group, which is a combination of a carbonyl group (C=O) and a hydroxyl group (-OH) attached to the same carbon atom. These compounds typically have the suffix "-oic acid" in their names. They are known for their acidic properties, which result from the ability of the carboxyl group to donate a hydrogen ion (H+).

When considering carboxylic acids in reactions, it is important to remember their formula, which can generally be represented as R-COOH, where "R" refers to an organic substituent. In butanoic acid, the "R" group is a three-carbon chain, making its full molecular formula C_3H_7COOH. This acid is a key reactant in forming amides when combined with amines.

Carboxylic acids can undergo various reactions, such as esterification and amide formation, due to the versatile carboxyl group. Their reactivity is pivotal for the synthesis of many different classes of organic compounds.

Amines

Amines are characterized by the presence of a nitrogen atom bonded to one or more alkyl or aryl groups. They are derivatives of ammonia (NH3) and are classified as primary, secondary, or tertiary, depending on the number of carbon-containing groups attached to the nitrogen.

In the context of the given exercise, methylamine is a primary amine, indicating that one of the hydrogen atoms in ammonia is replaced by a methyl group (CH3). Its chemical formula is CH3NH2. Amines are known for their nucleophilic properties, which means they can donate a pair of electrons during reactions. This makes them capable of forming bonds with electrophiles, such as the carbonyl carbon in carboxylic acids.

The role of amines in amide formation is crucial, as they participate in the reaction with carboxylic acids by bonding through their nitrogen atom to the carbonyl carbon of the acid, eventually leading to the elimination of water and the creation of an amide bond.

Chemical Equations

Chemical equations are a symbolic representation of a chemical reaction where reactants are transformed into products. Writing a balanced chemical equation is essential for accurately depicting the quantities and substances involved in a reaction.

In an equation, the reactants are listed on the left side and the products on the right, separated by an arrow that signifies the direction of the reaction. Balancing equations involves ensuring that the number of each type of atom appears the same on both sides of the equation.

For the reaction between butanoic acid and methylamine, the balanced chemical equation is:

• Reactants: C_3H_7COOH + CH_3NH_2
• Products: C_3H_7CONHCH_3 + H_2O

This equation not only shows the formation of the amide N-methylbutanamide but also highlights the production of water as a byproduct. Balance provides insight into the stoichiometry of the reaction, guiding how much reactant is necessary to create a specified amount of product.