Acetaldehyde

What is Acetaldehyde(C₂H₄O or CH₃CHO)?

It is an organic chemical compound with the chemical name Acetaldehyde. Acetaldehyde is also called MeCHO. It is a colourless organic liquid having a molecular formula C2H4O, also known as CH3CHO. IUPAC name of Acetaldehyde is ethanal. It has a pungent odor.

It is soluble in water and has a suffocating smell. It is non-corrosive to many metals but when it has a narcotic action and can cause mucous irritation. It can damage our liver. When we drink alcohol it breaks and forms Acetaldehyde. It is completely soluble in water.

Acetaldehyde is usually used as an intermediate in the production of acetic acid, also it is used in the manufacturing of perfumes, drugs, flavouring agents, dyes, etc. When Acetaldehyde is applied externally for prolonged periods it is toxic.  


Properties of Acetaldehyde- C2H4O or CH3CHO

  1. Molecular weight: 44.05 g/mol

  2. Density: 0.784 g/cm3

  3. Boiling point: 20.2 °C

  4. Melting point: -123.5 °C

  5. Colour: Colourless

  6. Odor: Pungent odor

  7. Solubility: It is soluble in water, ethanol, benzene, acetone, and slightly soluble in Chloroform.


Acetaldehyde Structure(C2H4O-Structure)

C- Carbon, H- Hydrogen, O- Oxygen


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Acetaldehyde (C2H4O OR CH3CHO) Occurrence

Acetaldehyde can be found in many plants and ripe fruits. Also, it is an intermediate in the ethanol metabolism, through the action of enzymes alcohol dehydrogenase that changes ethanol to acetaldehyde.


Uses of Acetaldehyde(C2H4O or CH3CHO)

  1. Acetaldehyde is primarily used to produce other chemicals.

  2. It is used to produce acetic acid.

  3. It is used to manufacture resin.

  4. It is used to manufacture disinfectants, drugs, and perfumes.

  5. It is used to produce polyvinyl acetate.

  6. It is used as a precursor to pyridine derivatives, crotonaldehyde, and pentaerythritol.

  7. Acetaldehyde is also used as a preservative for fruit and fish in the manufacture of vinegar, yeast, etc.

  8. It is used as a solvent in some industrial processes such as the manufacturing of paper, tanning, and rubber.

  9. Also, we use it in the production of n-butyraldehyde.

  10. It is used in leather tanning, as a denaturant for alcohol, in fuel mixtures, as a hardener for gelatin fibres, in glue and casein products.


Solved Examples

1. How to prepare acetaldehyde by dehydrogenation of ethanol?

Solution: Acetaldehyde can be prepared acetaldehyde from the dehydrogenation of ethanol by using copper as a catalyst in this reaction. At 260-28000C, the ethanol reacts over the catalyst to form acetaldehyde:

CH3CH2OH + ½ O2 → CH3CHO + H2O


2. How to prepare Acetaldehyde?

One of the methods of preparation of Acetaldehyde is the hydration of acetylene or ethylene by the Wacker process in which copper or palladium is the catalyst:

2CH2=CH2 + O2 → 2CH3CHO

Acetaldehyde was produced by the hydration of acetylene in which mercury (II) salts serve as a catalyst Before the Wacker process,

C2H2+ H2O + Hg2 → CH3CHO + Hg

Temperature maintained during the reaction is 90-950C, and the formed acetaldehyde is separated from water and mercury and cooled to 25-300C

Oxidation of ethanol is another method  where partial dehydrogenation of ethanol produces acetaldehyde in the presence of copper as a catalyst:

CH3CH2OH → CH3CHO + H2

Ethanol vapour is passed at a temperature of 260-2900C in this process.


Fun Facts

  1. Acetaldehyde is a clear liquid that burns easily. Acetaldehyde has a strong fruity odour that in high concentration can make breathing difficult.

  2. If acetaldehyde can be in contact with your eyes, flush them with large amounts of water for at least 15 minutes. Lift the lower and upper lids from time to time. Get medical attention. If acetaldehyde can be in contact with your skin, gently wash the skin with soap and water for 15 minutes. If this does not help, get medical attention.

  3. Acetaldehyde can hurt our heart and blood vessels. Other studies on animals show that breathing acetaldehyde can severely damage the lungs and cause cancer. Repeated exposure to acetaldehyde in the air may cause cancer in humans. When we drink alcohol, our liver transforms acetaldehyde into an acid. It can damage our liver.

  4. It is very interesting that Acetaldehyde is completely soluble in water and tends to form a long chain.

FAQ (Frequently Asked Questions)

1. What is Acetaldehyde and Where can it be Found?

Acetaldehyde is generally found in various plants, ripe fruits, vegetables, smoke from tobacco, gasoline, and exhaust from the engine. This material is commonly used as a flavouring agent and as an intermediate in alcohol metabolism in the manufacture of acetic acid, perfumes, dyes, and medicines.


Acetaldehyde is mainly found in nature in many foods such as ripe fruits, cheese, and heated milk.

Also, it is an intermediate in the ethanol metabolism, through the action of enzymes alcohol dehydrogenase that changes ethanol to acetaldehyde.

2. What are the Health Effects of Acetaldehyde and how does it Affect our Liver?

Short-term exposure to Acetaldehyde results in effects that include eye, skin, and respiratory tract irritation. Symptoms of long-term acetaldehyde poisoning mimic those to alcoholism.


If we drink alcohol, your body breaks down the alcohol into a chemical called Acetaldehyde. Acetaldehyde damages your DNA and prevents your body from repairing the damage. Our cell’s instruction manual is DNA which controls a cell’s normal growth and function. When DNA is damaged, a cell can start growing out of control and create a cancer tumor. A toxic buildup of acetaldehyde can increase your cancer risk.


Acetaldehyde can damage our liver because that is where most alcohol is broken down into the toxic by-product. Alcohol is instead metabolized in the pancreas and the brain, where acetaldehyde can also damage our cells and tissues.