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What Are Aromatic Aldehydes?

Ray Hawk
Ray Hawk

Aromatic aldehydes are organic chemical compounds that contain a carbon hydroxide radical or group, CHO, and are used as precursor chemicals in the pharmaceutical and plastics industries. The simplest of aromatic aldehydes is benzaldehyde, C6H5CHO, which is an almond extract that is used as a flavoring, and as an ingredient in some dye and plastics production. Many commercial preparations of these aldehydes exist for a variety of industrial uses. Tolualdehyde or p-tolualdehyde (PTAL), is used as a intermediate compound in agricultural and pharmaceutical products, p-ethylbenzaldehyde (EBAL) is used as a flavor and fragrance, and p-isobutylbenzaldehyde (IBBAL) is an additive for plastic resins. The smallest examples of aromatic aldehydes such as benzaldehyde are soluble in water, though most of them also tend to be very flammable.

Aldehydes and ketones are related compounds where an aldehyde contains at least one hydrogen atom attached to a carbonyl group of a carbon-oxygen bond. A ketone contains two alkyl groups, CnH, attached to the carbon atom of the carbonyl group. The two most commonly used aromatic aldehydes and aromatic ketones are formaldehyde and acetone, respectively. Formaldehyde is a widely used preservative and acetone is the main ingredient in many solvents. As of 2009, approximately 6,000,000,000 pounds (2,721,554,220 kilograms) of formaldehyde were created annually in industry and 11,243,575,400 pounds (5,100,000,000 kilograms) of acetone.

Vanillin is an aromatic aldehyde obtained from vanilla beans.
Vanillin is an aromatic aldehyde obtained from vanilla beans.

There are literally hundreds of different varieties of aromatic aldehydes and ketones manufactured by the chemical industry that are used to produce plastics and dyes. While they are commonly used to synthesize other chemicals for use in agriculture and pharmaceuticals as well, their most important consumer application, aside from formaldehyde and acetone production is as perfumes and flavoring agents. Several widely used examples of these aldehydes are obtained as natural derivatives, with benzaldehyde being derived from almonds, cinnamaldehyde from cinnamon, and carvone from caraway seeds as a spearmint flavor. Vanillin is another example that is obtained from vanilla beans, or can be prepared synthetically, and is known commercially as 3-methoxy-4-hydroxybenzaldehyde, (CH3O)(OH)C6H3CHO. Aromatic esters are related compounds with hydroxyl alcohol groups, which are also used as lighter weight fragrances in consumer products.

Esters, ketones, and aromatic aldehydes also have chemical components that make them important in human biological functions. Carbohydrates such as sugars and starches are based on compounds that contain ester hydroxyl groups, or aldehydes and ketones. Steroids produced by the human body, such as testosterone, cortisone, and progesterone, are ketones as well, and retinal is an aldehyde that is essential for human vision.

Discussion Comments


How safe are they if consumed in food?


Acetone is a powerful nail polish remover. I buy the non-acetone kind, because it isn’t as harsh on my nails.

My friend owns a salon, and I was there one night waiting for her to get through with a haircut and go out to dinner with me. I knew it would be awhile, so I asked if I could use her nail polish remover and polish to do my nails.

All she had was acetone remover. It took the polish off rapidly, but it also stripped my nails of their natural oils. They became rough, like hair that has been overprocessed.


Formaldehyde is definitely aromatic, but not in a good way. I remember the smell of it from biology class. We had to dissect several things that were preserved in it, and it came to represent death and disgust to me.

Somehow, my folder in which I wrote observations during the dissections started smelling like formaldehyde. I didn’t spill any on it, but I guess just being around the stuff made it stink.

I must say that it is a strong preservative, though. Anything that can keep a cow’s eye intact for future transport and dissection has to be powerful.


Good points.

This shows how some very complex sounding chemical names can actually refer to simple scents and flavors we use all the time, like almond and vanilla.


I didn’t know they were called aromatic aldehydes, but I frequently use extracts in my aromatic diffuser to make the house smell nice. Most people use essential oils, but I like to make use of what I already have around the house.

The diffuser suspends a small glass bowl several inches above a candle tray. I place a few drops of vanillin in the glass bowl. Then, I put a small tealight candle in the tray and light it. As it burns, it heats up the vanillin, and before long, the house smells like cookies must be in the oven.


I use aromatic aldehydes in cooking frequently. Just about every recipe I have for cookies, brownies, or cakes requires the addition of vanillin, or vanilla extract. I find that it gives a strong and distinct flavor to foods that might otherwise be a bit bland.

I also use almond extract to give drinks or desserts a cherry flavor. Almonds and cherries share a compound that can be found in this aromatic aldehyde, so their flavors are similar. I can even make cherry cola simply by adding a few drops of almond extract to a glass of pop.

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    • Vanillin is an aromatic aldehyde obtained from vanilla beans.
      By: Picture Partners
      Vanillin is an aromatic aldehyde obtained from vanilla beans.