Uses of Aldehydes and Ketones: Formulas, Physical & Chemical Uses

Uses of Aldehydes and Ketones: Did you know the flavouring agent in vanilla ice cream is an aldehyde? Which compound is responsible for the fragrance in jasmine flowers? The flavouring agent in Vanilla ice cream is an aromatic aldehyde commonly known as vanillin, which is chemically known as \(4-\) hydroxy \(-3-\) methoxy Benzaldehyde.

Jasmine gets its fragrance from a cyclic ketone commonly known as Jasmone. Similarly, there are many other aldehyde and ketone that are commonly used in our day-to-day life. Let’s learn some more uses of aldehydes and Ketones in this article.

Aldehydes and Ketones

Aldehydes and Ketones are the organic compounds that contain a carbonyl functional group \(\left( { > {\rm{C}} = {\rm{O}}} \right)\) with structures \(\left( {{\rm{R}} – {\rm{CHO}}} \right)\) for aldehydes and \(\left( {{\rm{R – CO – }}{{\rm{R}}^\prime }} \right)\) for ketones. Here, \({\rm{R}}\) and \({{{\rm{R}}^\prime }}\) denotes substituents of carbon. 

The aldehyde functional groups comprise a carbon atom attached to an oxygen atom through a double bond and a hydrogen atom through a single bond. The general structural formula of aldehydes is shown below, where \({\rm{R}}\) refers to the alkyl or aryl group.

An aldehyde group always lies at the end of a carbon chain. The general molecular formula of the homologous aldehyde series is \({{\rm{C}}_{\rm{n}}}{{\rm{H}}_{{\rm{2n + 1}}}}{\rm{CHO}},\) where \({\rm{n = 1,2,3 \ldots }}\)

The general structural formula of ketones is shown below:

The ketonic functional group always lies within the carbon chain. Hence, the simplest compound with the ketonic functional group is acetone.

Uses of Aldehydes

1. Formaldehyde is a common chemical found easily in biological laboratories. The main use of formaldehyde is preparing formalin, a \({\rm{40\% }}\) solution of formaldehyde in water. This solution helps in the preservation of biological specimens.

2. The phenol-formaldehyde resin, commonly known as Bakelite, is widely used in plastics, coatings, and adhesives.

2. Urea-formaldehyde \(\left( {{\rm{UF}}} \right){\rm{,}}\) also known as urea-methanal, is a non-transparent thermosetting synthetic resin or polymer. It is produced from urea and formaldehyde and consists of \({\left[ {\left( {\rm{O}} \right){\rm{CNHC}}{{\rm{H}}_{\rm{2}}}{\rm{NH}}} \right]_{\rm{n}}}\) repeat units. These resins are used in adhesives, finishes, particleboard, medium-density fibreboard \(\left( {{\rm{MDF}}} \right){\rm{,}}\) and molded objects.

3. Aldehydes are a precursor to many industrial processes such as glue preparation, tanning, and polymeric products.

4. Aldehydes such as Glutamaldehyde also act as insecticides, antiseptics, and fungicides. It attacks the cell membrane and cell wall of bacterias and fungi, inhibiting their functionality.

5. Formaldehyde is also used in photography and drug testing.

6. Acetaldehyde is used in the production of acetic acid and pyridine derivatives.

7. Aldehydes are widely used in perfumes and fragrances and the cosmetic and dye industry.

8. Aldehydes are also used as artificial flavouring agents such as Benzaldehyde (aromatic aldehyde) which is added to incorporate almond flavour into various food products. It is an essential component for the production of perfumes, cosmetic products, and dyes. It also acts as a bee repellant.

9. Cinnamaldehyde is used to incorporate cinnamon flavour in foods. Similarly, vanillin acts as the main flavouring agent in vanilla beans.

10. Aldehydes play an important part in the caramelisation of sugars. When sugar is cooked slowly, the aldehyde group present in sugar is converted into an unsaturated aldehyde by the amino acids. This gives sugar the characteristic brown colour of caramel. 

11. Retinal (an aldehyde) on combining with a protein (opsin) forms rhodopsin responsible for the process of vision.

12. Indian cooking is incomplete without the use of certain herbs, such as coriander. The characteristic smell of coriander is due to the presence of certain aldehydes. Coriander is composed of around \(40\) different organic compounds, with \(82\) per cent of these being aldehydes with \(9–10\) carbon atoms, and it is these that are largely responsible for the aroma of coriander leaves

Uses of Ketones

1. The most common and the simplest of all ketones is acetone. It is most commonly used as a nail paint remover and paint thinner. 
2. Acetone is infinitely soluble in water in all proportions and dissolves many organic compounds. Due to its low boiling point \(\left( {{\rm{56}}\,^\circ {\rm{C}}} \right),\) it can be easily removed by evaporation when no longer needed.
3. Ketones act as an excellent solvent for certain types of synthetic fibres and plastics.
4. Ketones are widely used in the cosmetic industry and for certain medicinal purposes such as chemical peeling procedures and acne treatments.
5. Ketone methadone is used to cure opiate addiction. Opiates release an excessive amount of dopamine hormone. Methadone binds to the dopamine receptor in the brain, thereby eliminating the user’s physical dependency on opiates.
6. Many ketones perform essential functions in humans and other living organisms. The steroid hormones such as progesterone, testosterone, cortisone and aldosterone are ketones.
7. Methyl ethyl ketone or Butanone is one of the common solvents used in the manufacture of textiles, varnishes, paint-thinners, paraffin wax, plastics, etc.
8. An aromatic ketone, acetophenone, is responsible for fragrances such as jasmine, honeysuckle, cherry, and strawberry.
9. A cyclic ketone called cyclohexanone is an important component in the production of nylon.

Summary

The difference between Aldehydes and Ketones is that the carbonyl carbon of an aldehyde is attached to a hydrogen atom. In contrast, the carbonyl carbon of a ketone is attached to two alkyl or aryl groups. Aldehydes are easily oxidizable due to their \({\rm{C – H}}\) bond (they are strong reducing agents).

The delicious scents of cookies baking in an oven are due to aldehydes. This article taught us how aldehydes and ketones are broadly used in different sectors such as food, pharmaceutical, fragrance, and cosmetics.

FAQs on Uses of Aldehydes and Ketones

Q.1. What are some aldehydes and ketones used in daily lives?
Ans: Some of the aldehydes used in daily lives are cinnamaldehyde (cinnamon bark), vanillin (vanilla ice creams), Benzaldehyde (almonds), and formaldehyde (preservation).
Some common ketones are acetone (nail polish remover), Butanone (acne treatment), Cyclohexanone (nylon).

Q.2. What is the functional group for aldehyde and ketone?
Ans: Aldehydes and Ketones are the organic compounds that contain a carbonyl functional group \(\left( { > {\rm{C}} = {\rm{O}}} \right)\) with structures \(\left( {{\rm{R}} – {\rm{CHO}}} \right)\) for aldehydes and \(\left( {{\rm{R – CO – }}{{\rm{R}}^\prime }} \right)\) for ketones. Here, \({\rm{R}}\) and \({{{\rm{R}}^\prime }}\) denotes substituents of carbon.

Q.3. How are ketones used in real life?
Ans: Ketones are generally used as catalysts and solvents in the chemical industry. These are products often used in paints and perfumes. Some of the major ketones are acetophenone, Butanone, and acetone.

Q.4. Aldehydes are found in which food?
Ans: Aldehydes are found in fruits and essential oils. These are mostly found in cinnamon bark, almonds, coriander leaves, vanilla beans.

Q.5. What are the uses of aldehyde?
Ans: Aldehydes are used to preserve, tanning, and as a germicide, fungicide, and insecticide for plants and vegetables, but their largest application is in producing certain polymeric materials such as bakelite novolac.

We hope this detailed article on the uses of aldehydes and ketones helped you in your studies. If you have any doubts, queries or suggestions regarding this article, feel to ask us in the comment section and we will be more than happy to assist you. Happy learning!