Question

Write equations to show the reaction of acetyl chloride with: (a) water, (b) ammonia, and (c) isopropyl alcohol.

Short answer

The balanced chemical equations for the reactions of acetyl chloride with water, ammonia, and isopropyl alcohol are: (1) Water reaction: \[ CH_3COCl + H_2O \rightarrow CH_3COOH + HCl \] (2) Ammonia reaction: \[ CH_3COCl + NH_3 \rightarrow CH_3CONH_2 + HCl \] (3) Isopropyl alcohol reaction: \[ CH_3COCl + (CH_3)_2CHOH \rightarrow CH_3COO(CH_3)_2CH + HCl \]

Step-by-step solution

(1) Acetyl chloride and water reaction.

To write the balanced equation for the reaction between acetyl chloride and water, we need first to identify the type of reaction. This is an example of nucleophilic addition-elimination reaction where water will act as a nucleophile and replace the chloride in acetyl chloride. The products are acetic acid and hydrochloric acid. The balanced chemical equation is: \[ CH_3COCl + H_2O \rightarrow CH_3COOH + HCl \]

(2) Acetyl chloride and ammonia reaction.

In the reaction between acetyl chloride and ammonia, ammonia will act as a nucleophile replacing chloride in acetyl chloride. The product of this reaction is acetamide and hydrochloric acid. The balanced chemical equation is: \[ CH_3COCl + NH_3 \rightarrow CH_3CONH_2 + HCl \]

(3) Acetyl chloride and isopropyl alcohol reaction.

When acetyl chloride reacts with isopropyl alcohol, it undergoes another nucleophilic addition-elimination reaction. Isopropyl alcohol replaces the chloride in acetyl chloride, forming isopropyl acetate and hydrochloric acid as products. The balanced chemical equation is: \[ CH_3COCl + (CH_3)_2CHOH \rightarrow CH_3COO(CH_3)_2CH + HCl \] These are the balanced chemical equations for the reactions of acetyl chloride with water, ammonia, and isopropyl alcohol.

Key concepts

Nucleophilic Addition-Elimination

The nucleophilic addition-elimination mechanism is a fundamental concept in organic chemistry. It primarily involves a nucleophile donating a pair of electrons and attacking a carbon center that has a leaving group attached. This process is called nucleophilic attack. When the nucleophile approaches, typically, a transient structure called a tetrahedral intermediate is formed.
This intermediate then collapses, wherein the leaving group departs, completing the elimination step and forming the final product.

• Nucleophile: An electron-rich species capable of donating electrons.
• Electrophile: The carbon center that was originally bonded to the leaving group.
• Leaving Group: Often a halide, which is easily displaced by the nucleophile.

This reaction is particularly common with acyl chlorides, like acetyl chloride, due to the presence of a highly reactive carbonyl group.

Acetyl Chloride Reactions

Acetyl chloride is a powerful acylating agent. It reacts readily with various nucleophiles, resulting in nucleophilic addition-elimination reactions. Let's consider a few examples of how acetyl chloride reacts with different nucleophiles:

• Water: Acts as a nucleophile to produce acetic acid and hydrochloric acid.
• Ammonia: Reacts to form acetamide and hydrochloric acid.
• Alcohols (such as isopropyl alcohol): Yield esters (like isopropyl acetate) and hydrochloric acid.

These reactions showcase the versatility of acetyl chloride and its proclivity to undergo nucleophilic substitution reactions.

Chemical Equations

In chemical reactions, balanced equations represent the conservation of mass and the stoichiometry of the reaction. When writing chemical equations, it is essential to ensure that the same number of each type of atom appears on both sides of the reaction. For instance, in the case of organic chemical reactions:

• Reactants such as acetyl chloride and a nucleophile (e.g., water, ammonia, alcohol) are represented on the left side.
• The corresponding products (e.g., acids, amides, esters, with hydrochloric acid) are shown on the right side.

Each reaction must feature a balanced equation, thereby maintaining the law of conservation of mass and providing clear insight into the transformation occurring in the reaction.

Reaction Mechanisms

Understanding reaction mechanisms is crucial to mastering organic chemistry. A reaction mechanism describes the step-by-step process that occurs at the molecular level. Each step illustrates how bonds are broken and formed, detailing the path from reactants to products.
In nucleophilic addition-elimination reactions involving acetyl chloride:

• Initiation involves the nucleophile attacking the electrophilic center of acetyl chloride.
• Intermediate formation involves a temporary unstable configuration.
• The final step involves the departure of the leaving group, usually a chloride ion, forming the end product.

Understanding these details helps predict the behavior of other similar compounds and reactions, solidifying the foundation for advanced organic chemistry concepts.