Aldehydes, Ketones And Carboxylic Acids

- Wondering why to study this chapter? Know the real world use of it!
Aldehydes: You'll Find Them Everywhere!
They're in your cake, they're in your perfume, they're inside you. Aldehydes are everywhere and there's no escaping them! Aldehydes have prominent odours and tastes, because of which they are mostly used in food and perfume industries. Not just that, they have lots of industrial uses as well. Let's look at some of the areas in which aldehydes make a difference in our daily lives:
The sweet smelling odour of vanilla extract is because of vanillin, an aldehyde, and the scent of almonds is because of benzaldehyde, also an aldehyde. Likewise, you'll find cinnamaldehyde (another aldehyde) in cinnamon bark. All these aldehydes are responsible for the yummy flavours in our favorite foods.
Did you know that the use of aromatic aldehydes in perfumes was popularised by Ernest Beaux, a Russian perfumer, in 1921 when he create the famous perfume Chanel No. 5? Aldehydes are being used in perfumes and colognes ever since.
Aldehydes are used to manufacture a number of products like synthetic resins, dyes, and so on. Formaldehyde, for example is used to produce polymers like bakelite, melamine, and adhesives. It is also used as a preservative, fungicide, and germicide. Apart from this aldehydes are also used as solvents, and as starting materials for making drugs, acids, and polymers.
The Many Uses of Ketones
Ketones, like aldehydes, have prominent odours. For instance, (R)-Muscone is responsible for the musky smell of the Himalayan musk deer.
Another ketone, 2-heptanone gives blue cheese its sharp smell. Ketones have many uses in our daily lives.
  • Some pleasant smelling ketones are used in perfumery.
  • Some ketones like acetophenone, carvone and jasmone are found in essential oils. They are known to have therapeutic properties like sedative and calming properties, analgesic properties, mucolytic and healing properties.
  • They are also used as solvents, as starting materials for other chemicals, in the manufacture of adhesives, in paint manufacture, rubber manufacture, printing and even electroplating. Methyl isobutyl ketone, one of the most used industrially used ketone, has applications in rubber and paints industry. It's market is so huge that it is expected to reach $800 million by 2025!
Carbonyls in Our Bodies
Aldehydes and ketones are critical for the normal functioning of our bodies. Some examples include carbohydrates, hormones like progesterone, testosterone and cortisone, and retinal. Retinal, which is an aldehyde, combines with the opsin protein inside the retina of our eyes to form rhodopsin. It is this rhodopsin that makes it possible for us to see the world!
Are You Aware of the Keto Diet?
If you know someone who's weight conscious, you'll have heard of the keto diet. This diet promotes ketosis in our body. Ketosis is a process in which the body has less carbohydrates to burn and so, it burns fat instead, resulting in the production of ketones like acetone, beta-hydroxybutyrate (BHB), and acetoacetate. A keto diet has more of fats and proteins and less carbohydrates. This diet was originally developed to treat epileptic children, but it has taken over the world as a weight-loss diet.
Finally, the Applications of Carboxylic Acids
  • Needless to say, carboxylic acids are used in a number of industries. For instance, methanoic acid is used to manufacture textiles, rubber, and leather.
  • Esters of carboxylic acids are used in making perfumes, deodorants and air fresheners. For example, benzoic acid.
  • Carboxylic acids like ethanoic acid and sodium benzoate (sodium salt of benzoic acid) are used in the food industry. Tartaric acid is used as an emulsifier, citric acid as an acidulant, and ascorbic acid as an antioxidant.
  • They also find applications in manufacture of soaps and detergents. For instance, palmitic acid and stearic acid.
  • Carboxylic acids are also used in manufacture of drugs like antibiotics, antihistamines and so on. The popular painkiller, Aspirin, is prepared using acetic and salicylic acid.
  • They are also used to manufacture cosmetics. AHAs (alpha hydroxy acids) are classic examples of this. Others like glycolic acids, citric and malic acids are used in skin-whitening, pore cleansing, anti-ageing and moisturising products.