Table of Contents
Identification of Primary, Secondary and Tertiary Alcohols
A primary alcohol has one carbon atom bonded to the alcohol group.
A secondary alcohol has two carbon atoms bonded to the alcohol group.
A tertiary alcohol has three carbon atoms bonded to the alcohol group.
Oxidation of Alcohol
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The oxidation of alcohols to aldehydes or ketones is a two step process. The first step is the oxidation of the alcohol to a ketone or aldehyde. The second step is the conversion of the ketone or aldehyde to the corresponding acid.
The oxidation of an alcohol to a ketone or aldehyde can be accomplished by treating the alcohol with a strong oxidizing agent, such as chromic acid or nitric acid. The oxidation of an alcohol to a ketone or aldehyde can also be accomplished by treating the alcohol with a mild oxidizing agent, such as pyridinium chlorochromate (PCC) or dichromate ion (Cr2O72-).
The conversion of a ketone or aldehyde to the corresponding acid can be accomplished by treating the ketone or aldehyde with a strong acid, such as hydrochloric acid or sulfuric acid. The conversion of a ketone or aldehyde to the corresponding acid can also be accomplished by treating the ketone or aldehyde with a mild acid, such as acetic acid or citric acid.
Oxidation of Alcohols
When an alcohol is oxidized, the hydrogen atom on the carbon atom attached to the oxygen atom is replaced by a oxygen atom. This process is called oxidation. The oxidation of an alcohol can be represented by the following equation:
Alcohol + Oxygen → Aldehyde + Water
In the equation, the alcohol is represented by the letter “R” and the aldehyde is represented by the letter “A.” The water is represented by the letter “H2O.”
Different Types of Alcohols
There are many types of alcohols, but they can be generally classified into two categories: primary and secondary.
Primary alcohols are those that are derived from a single carbon molecule. They are typically volatile and flammable, and have a characteristic “burning” odor. Examples of primary alcohols include ethanol and methanol.
Secondary alcohols are those that are derived from two carbon molecules. They are typically less volatile and less flammable than primary alcohols, and have a less pronounced “burning” odor. Examples of secondary alcohols include isopropanol and butanol.
Different types of Alcohols – Oxidation and Reduction of Alcohols
The oxidation of an alcohol produces aldehyde or ketone, while the reduction of an alcohol produces an alkane.
Oxidation of Alcohols Mechanism
The oxidation of an alcohol to an aldehyde or ketone is a two-step process. In the first step, the alcohol is oxidized to an aldehyde. In the second step, the aldehyde is oxidized to a ketone.
Oxidation of Alcohols Mechanism
The oxidation of an alcohol to an aldehyde or ketone is a two-step process. In the first step, the alcohol is oxidized to an aldehyde. In the second step, the aldehyde is oxidized to a ketone.
The first step in the oxidation of an alcohol is the formation of an aldehyde. The aldehyde is formed by the addition of an oxygen atom to the carbon atom that is attached to the hydroxyl group. The addition of the oxygen atom is called a oxidation reaction.
The second step in the oxidation of an alcohol is the formation of a ketone. The ketone is formed by the addition of a second oxygen atom to the carbon atom that is attached to the hydroxyl group. The addition of the second oxygen atom is called a oxidation reaction.
Oxidation of Alcohols to Aldehydes and Ketones
The oxidation of an alcohol to an aldehyde or ketone proceeds through the formation of an enolate ion. The enolate ion is then attacked by the oxygen atom of the alcohol, forming the aldehyde or ketone.
The following mechanisms illustrate the oxidation of an alcohol to an aldehyde. In both mechanisms, the enolate ion is formed by the deprotonation of the alcohol with a strong base.
The first mechanism involves the formation of a strong enolate ion with the use of a strong base, such as potassium hydroxide (KOH). The enolate ion is then attacked by the oxygen atom of the alcohol, forming the aldehyde.
The second mechanism involves the formation of a weak enolate ion with the use of a weak base, such as sodium ethoxide (NaOEt). The enolate ion is then attacked by the oxygen atom of the alcohol, forming the aldehyde.
Oxidation of Alcohols to Aldehydes and Ketones
The oxidation of an alcohol to an aldehyde or ketone can be accomplished with a variety of oxidizing agents, including chromium trioxide (CrO 3 ), potassium permanganate (KMnO 4 ), and potassium dichromate (K 2 Cr 2 O 7 ). These oxidizing agents are all strong oxidizing agents that convert alcohols to aldehydes and ketones by removing the hydrogen atom from the alcohol molecule.
The following reaction represents the oxidation of an alcohol to an aldehyde using chromium trioxide as the oxidizing agent.
The following reaction represents the oxidation of an alcohol to a ketone using chromium trioxide as the oxidizing agent.
The following reaction represents the oxidation of an alcohol to an aldehyde using potassium permanganate as the oxidizing agent.
The following reaction represents the oxidation of an alcohol to a ketone using potassium permanganate as the oxidizing agent.
Identification test of Alcohol – Selective Oxidation of Alcohols
This identification test of alcohol uses selective oxidation to determine the presence of an alcohol.
A small amount of Benedict’s solution is added to a test tube containing a suspected alcohol. The test tube is then heated, and the presence of an alcohol will cause a color change in the Benedict’s solution.
Identification test of Alcohol – Selective Oxidation of Alcohols
This identification test of alcohol uses a selective oxidation of alcohols to identify the presence of an alcohol functional group.
A small amount of Benedict’s solution is added to a sample of the unknown compound. If an alcohol is present, it will be selectively oxidized to an aldehyde or ketone. This will cause a change in the color of the Benedict’s solution from blue to yellow.
