November 29, 2021
You know me from Middle Eastern foods—and tacos.
What molecule am I?
Image of Cuminaldehyde

November is flavor and aroma month!

Cuminaldehyde, an aromatic aldehyde, gets its name from one of its main natural sources: the cumin plant (Cuminum cyminum) that grows in countries from Turkey across to India. In addition to cumin, cuminaldehyde is found in the essential oils of eucalyptus, myrrh, and cassia.

In small amounts, cuminaldehyde has a pleasant, herbal aroma; however, it also has an acrid, burning taste. As the hazard information table shows, direct exposure can have some unpleasant consequences.

Cumin has been used as a flavoring agent for centuries; cuminaldehyde has been in the chemical literature since at least the 1880s. In volume 2 (1880) of the Journal of the American Chemical Society (then called the American Chemical Journal), an abstract of an article about derivatives of stilbene (1,2-diphenylethylene) describes a reaction between “cumic aldehyde” and phenylacetic acid to form isopropylstilbene.

Almost 70 years later, Nathan N. Crounse at the Hilton-Davis Chemical Co. (Cincinnati) reported a synthesis of cuminaldehyde that uses the high-pressure Gattermann–Koch reaction to formylate cumene (isopropylbenzene) with carbon monoxide. The aldehyde can also be prepared by the reduction of p-isopropylbenzoyl chloride.

Today, most commercial cuminaldehyde is synthetic. It is sold as an ingredient for flavoring agents, perfumes, and other aroma-containing products. It also has several purported medicinal uses (e.g., against pain, inflammation, nausea, and skin conditions), but the effects are largely anecdotal. A derivative, cuminaldehyde thiosemicarbazone1, has been studied for activity against the hepatitis C virus and colon cancer.

A final note: Cumin is the main flavor ingredient in taco sauce. The next time you go out for Taco Tuesday, you have cuminaldehyde to thank.

1. CAS Reg. No. 3811-20-9.

Cuminaldehyde hazard information*

Hazard class**GHS code and hazard statement
Flammable liquids, category 4H227—Combustible liquidChemical Safety Warning
Acute toxicity, oral, category 4H302—Harmful if swallowedChemical Safety Warning
Acute toxicity, dermal , category 4H312—Harmful in contact with skinChemical Safety Warning
Skin corrosion/irritation, category 2H315—Causes skin irritationChemical Safety Warning
Serious eye damage/eye irritation, category 2AH319—Causes serious eye irritationChemical Safety Warning
Acute toxicity, inhalation, category 4H332—Harmful if inhaledChemical Safety Warning

*Compilation of selected safety data sheets.
**Globally Harmonized System (GHS) of Classification and Labeling of Chemicals. 
Explanation of pictograms.

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fast facts

CAS Reg. No.122-03-2
Benzaldehyde, 4-(1-methylethyl)-
Empirical formulaC10H12O
Molar mass148.20 g/mol
AppearanceColorless to yellow liquid
Boiling point235–236 °C
Water solubilityInsoluble
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