Question

In the formation of an ester, which bond of a carboxylic acid is broken, \(\mathrm{C}-\mathrm{OH}\) or \(\mathrm{CO}-\mathrm{H}\) ?

Short answer

In the formation of an ester, the bond that is broken in a carboxylic acid is the C-OH bond. This occurs during the esterification reaction between a carboxylic acid (R-CO-OH) and an alcohol (R'-OH), resulting in an ester (R-CO-O-R') and water.

Step-by-step solution

Write the general reaction for esterification

Esterification is the chemical reaction between a carboxylic acid and an alcohol, which results in the formation of an ester and water. The general reaction can be represented as follows: Carboxylic Acid + Alcohol ⟶ Ester + Water

Write the structural formulas for the reactants

In order to analyze which bond is broken during este formation, let's write the structural formulas of carboxylic acid (RCOOH) and alcohol (R'OH): Carboxylic Acid: R-CO-OH Alcohol: R'-OH Here, "R" and "R'" are alkyl groups which can vary in length and structure.

Analyze the esterification reaction and identify the broken bond

During the reaction, the hydrogen atom from the alcohol (R'-OH) and the hydroxyl group (OH) from the carboxylic acid (RCOOH) will combine to form water (H2O). This will result in the ester, formed from the remaining parts of carboxylic acid and alcohol: Ester: R-CO-O-R' The bond that is broken during ester formation is the C-OH bond of the carboxylic acid. The CO-H bond is not broken during this reaction. So, the answer to the question is: The C-OH bond of the carboxylic acid is broken during the formation of an ester.

Key concepts

Carboxylic Acid

Carboxylic acids are organic compounds that contain a carboxyl group, which is composed of a carbon atom bound to an oxygen atom double-bond (\(\text{C}=\text{O}\)) and to a hydroxyl group (\(\text{O}-\text{H}\)). This functional group is represented as -COOH. Carboxylic acids are well-known for their acidic properties due to the ability to donate an He+ ion from the carboxyl group.

They are commonly used in organic synthesis and are essential building blocks for more complex molecules. In esterification reactions, the carboxylic acid reacts with an alcohol. During this reaction, an ester and water are produced.

A common example of a carboxylic acid is acetic acid, which is found in vinegar. This versatility and reactivity make carboxylic acids a crucial component in chemical reactions, especially in the production of synthetic esters.

Alcohol

Alcohols are organic compounds characterized by the presence of one or more hydroxyl (\(\text{O}\text{H}\)) groups attached to a carbon atom. They are typically represented as \(\text{R}-\text{OH}\), where R denotes an alkyl group.

Alcohols have diverse applications and are widely used as solvents, antiseptics, and, importantly, as reactants in the formation of esters.

In the process of esterification:

• The hydrogen atom from the \(\text{OH}\) group of the alcohol interacts with the \(\text{OH}\) group of the carboxylic acid.
• This leads to the release of a water molecule (\(\text{H}_2\text{O}\)) and the formation of an ester.

The main role of alcohol in esterification is to donate a hydrogen atom that combines with the hydroxyl group of the carboxylic acid to form water, facilitating the formation of an ester bond.

C-OH bond

The \(\text{C}-\text{OH}\) bond in organic chemistry refers to the connection between a carbon atom and a hydroxyl group. In carboxylic acids, this bond is part of the carboxyl group.

During esterification, the \(\text{C}-\text{OH}\) bond of the carboxylic acid is broken. This breakage is a crucial step since the \(\text{OH}\) part of the \(\text{C}-\text{OH}\) bond combines with the hydrogen atom from the alcohol.

This formation of water (H\(_2\)O) which is a byproduct of the reaction, is vital for the creation of the ester ligament that arises between the remainder of the carboxylic acid and the alcohol.

Understanding the breaking of the \(\text{C}-\text{OH}\) bond helps to comprehend the transformation of the molecular structure from individual reactants into an entirely new compound, the ester.

Chemical Reaction

A chemical reaction is a process whereby reactant molecules undergo a transformation to create one or more different products. This transformation involves the rearrangement of atomic bonds, leading to changes in molecular structures.

In esterification, the reactants are a carboxylic acid and an alcohol, which react to form an ester and water. This reaction typically requires an acid catalyst and involves several key steps:

• Breaking the \(\text{C}-\text{OH}\) bond of the carboxylic acid.
• Formation of the water molecule from the hydroxyl group of the acid and the hydrogen atom of the alcohol's hydroxyl group.
• Creation of a new ester bond between the leftover portions of the acid and alcohol.

Chemical reactions such as esterification are instrumental in creating new compounds with different properties. This is essential for the development of various industrial products, including esters, which are commonly used in perfumes, flavorings, and plastics.