Amide Hydrolysis - Online Tutor, Practice Problems & Exam Prep

Acidic hydrolysis of amides involves the reaction of an amide with aqueous acid, typically hydrochloric acid, under heat, resulting in a carboxylic acid and an ammonium ion. The carbonyl carbon gains a hydroxyl group, transforming into a carboxylic acid, while the nitrogen becomes positively charged by gaining two hydrogen atoms, forming an ammonium ion. In contrast, basic hydrolysis uses hydroxide ions to cleave the amide bond, producing a carboxylate anion and a neutral amine. Here, the carbonyl carbon gains an oxygen atom with a negative charge, while the nitrogen gains one hydrogen atom, resulting in a neutral amine.

Acidic Hydrolysis Concept 1

Hey, everyone. So we're going to take a look at acidic hydrolysis of amides. Now we're going to say that under this reaction, an amide is hydrolyzed into a carboxylic acid and an ammonium ion in an acidic medium. Now if we take a look at this general reaction, we have our amide here and with it our amide bond that connects our nitrogen to our carbonyl group. Under this reaction, we use basically aqueous acid, meaning that we have hydrochloric acid dissolved in water, and we accompany it with heat. Basically what happens is that in this reaction, the carbonyl carbon is going to gain a hydroxyl group. Doing this transforms it into a carboxylic acid. And at the same time, we're going to have the nitrogen itself gains 2 hydrogen atoms, and thereby becomes an ammonium ion. Remember when nitrogen makes 4 bonds it becomes positively charged. It transitions from being a neutral amine to an ammonium ion. So just remember under acidic hydrolysis we make a carboxylic acid and an ammonium ion.

Acidic Hydrolysis Example 1

Determine the products when 3,3-dimethylhexanamide is treated with an aqueous hydrochloric acid solution. So remember, in this reaction, we're going to cut this amide bond. And what's going to occur is that the carbonyl carbon gains an OH group. So, we create a carboxylic acid. At the same time, the nitrogen itself will gain 2 hydrogen atoms. Since nitrogen already contains 2 hydrogens, it's going to gain another 2. So at the end, we'll have 4 hydrogens on the nitrogen. It'll be making 4 bonds, so it'll be positively charged. So here, we make an ammonium ion as the second product. So this would be our answer for this particular example question. We created a carboxylic acid and the ammonium ion.

Name the carboxylic acid formed when the following amide undergoes an acidic hydrolysis reaction.

• A. 2-bromopentanoic acid
• B. 3-bromohexanoic acid
• C. 3-bromopentanoic acid
• D. 3-bromohexanoate

Basic Hydrolysis Concept 2

In this video, we're going to take a look at basic hydrolysis of amides. Now, under this reaction, we're going to say that the hydroxide ion, which is OH-, dissolved in water reacts with an amide. The reaction cleaves or cuts the amide bond to create a carboxylate anion and an amine. Now, if we take a look here at this general reaction, we're going to cut this amide bond by using aqueous hydroxide. So that just means it's dissolved in water and accompanied by some heat.

So essentially, what happens here is that the carbonyl carbon will gain an O- because a carboxylate anion is just the conjugate base form of a carboxylic acid. So instead of having an OH group, it has an O minus group. And the nitrogen here would only gain 1 hydrogen atom. Here we create a neutral amine. So under basic conditions, we're not making a carboxylic acid, we're making its conjugate base, which is our carboxylate anion. And for the amine, it's going to be a neutral amine that's being formed.

Basic Hydrolysis Example 2

Determine the products when N-ethyln-methylbutanamide is treated with an aqueous hydroxide ion solution. Now, before we do this question, remember, when it comes to our N substituents, you have to have your N capitalized and italicized. Right. So that's the name of this particular amide. Now, under basic hydrolysis, we're going to cut the amide bond. When we do that, we're going to make a carboxylate anion. So the carbonyl group gets an O negative attached to it, and then the amide, well, the nitrogen part of the amide, that nitrogen, all it's going to do is gain 1 hydrogen and stay as a neutral amine. Right? So in this particular question, we make a carboxylate anion product as well as a neutral amine.

Determine the carboxylate anion formed in the following reaction between the given amide and aqueous base.

• A.
• B.
• C.
• D.

Determine the nitrogen product formed when the following amide undergoes acidic hydrolysis.

• A.
• B.
• C.
• D.

What was the starting material that created the following products?

• A.
• B.
• C.
• D.

Here’s what students ask on this topic:

What is the mechanism of acidic hydrolysis of amides?

In acidic hydrolysis of amides, the reaction occurs in the presence of aqueous acid, typically hydrochloric acid, and heat. The carbonyl carbon of the amide gains a hydroxyl group (OH), transforming into a carboxylic acid. Simultaneously, the nitrogen atom in the amide gains two hydrogen atoms, forming an ammonium ion. The overall reaction can be summarized as:

${R-\mathrm{CONH}}_2+{H-\mathrm{Cl}}_2+H{O}_2\to {R-\mathrm{COOH}}_2+{\mathrm{NH}}_4+{\mathrm{Cl}}_2$

What are the products of basic hydrolysis of amides?

In basic hydrolysis of amides, the reaction occurs with hydroxide ions (OH^-) in water and heat. The amide bond is cleaved, resulting in the formation of a carboxylate anion and a neutral amine. The carbonyl carbon gains an oxygen atom with a negative charge (O^-), forming the carboxylate anion, while the nitrogen gains one hydrogen atom, forming a neutral amine. The overall reaction can be summarized as:

${R-\mathrm{CONH}}_2+{\mathrm{OH}}_{\mathrm{-}}+H{O}_2\to {R-\mathrm{COO}}_{\mathrm{-}}+{\mathrm{NH}}_3$

How does the acidic hydrolysis of amides differ from basic hydrolysis?

Acidic hydrolysis of amides involves the use of aqueous acid (e.g., HCl) and heat, resulting in the formation of a carboxylic acid and an ammonium ion. The carbonyl carbon gains a hydroxyl group (OH), and the nitrogen gains two hydrogen atoms, forming an ammonium ion. In contrast, basic hydrolysis uses hydroxide ions (OH^-) and heat, producing a carboxylate anion and a neutral amine. The carbonyl carbon gains an oxygen atom with a negative charge (O^-), and the nitrogen gains one hydrogen atom, forming a neutral amine. The key difference lies in the products: acidic hydrolysis yields a carboxylic acid and ammonium ion, while basic hydrolysis yields a carboxylate anion and a neutral amine.

What conditions are required for the hydrolysis of amides?

The hydrolysis of amides can occur under either acidic or basic conditions, both requiring heat. For acidic hydrolysis, an aqueous acid such as hydrochloric acid (HCl) is used. The reaction produces a carboxylic acid and an ammonium ion. For basic hydrolysis, an aqueous solution of hydroxide ions (OH^-), such as sodium hydroxide (NaOH), is used. This reaction produces a carboxylate anion and a neutral amine. In both cases, heat is necessary to facilitate the reaction and ensure the amide bond is cleaved effectively.

Why is heat necessary for the hydrolysis of amides?

Heat is necessary for the hydrolysis of amides because it provides the energy required to break the strong amide bond. The amide bond is relatively stable and requires significant energy to be cleaved. In both acidic and basic hydrolysis, heat helps to accelerate the reaction by increasing the kinetic energy of the molecules, thereby facilitating the interaction between the amide and the hydrolyzing agents (acid or base). Without sufficient heat, the reaction would proceed very slowly or might not occur at all.