What molecule am I?
Allyl isothiocyanate (AITC) is a natural compound found in cruciferous vegetables (family Brassicaceae) such as horseradish, mustard, radish, and wasabi. It first appeared in the chemical literature in three 1890s articles about isothiocyanates by Augustus E. Dixon at Queen鈥檚 College, Galway (Ireland, now the University of Galway). At the time, AITC was called 鈥渁llylthiocarbimide鈥�.
It was not until 1964 that AITC appeared in a biological study. Misao Kojima at Fukuoka University (Japan) identified it in dried wasabi (Japanese horseradish, Wasabia japonica) roots. The article even described the preparation of a wasabi sauce that contained 10 parts wasabi flour, 60 parts horseradish flour, 30 parts mustard flour, and 1.5 parts green pigment.
In a follow-up paper, Kojima and co-workers reported a gas chromatography study on wasabi powder in which they found that it contains substantial amounts of AITC and phenethyl isothiocyanate1 (PEITC), whereas horseradish (Armoracia rusticana) powder contains mainly PEITC.
In addition to natural sources, AITC is synthesized from allyl chloride2 and potassium thiocyanate3. The synthetic product is not used in foods; its primary uses are in crop protection products and bactericides.
Many of us enjoy wasabi, mustard, and other sauces; but it鈥檚 worth noting that AITC by itself is pretty nasty stuff, as shown in the hazard information table. It likely has more hazard statements than any other Molecule of the Week.
1. CAS Reg. No. 2257-09-2.
2. CAS Reg. No. 107-05-1.
3. CAS Reg. No. 333-20-0.
Allyl isothiocyanate hazard information*
| Hazard class** | GHS code and hazard statement | |
|---|---|---|
| Flammable liquids, category 3 | H226鈥擣lammable liquid and vapor |  |
| Acute toxicity, oral, category 3 | H301鈥擳oxic if swallowed |  |
| Acute toxicity, dermal, category 2 | H310鈥擣atal in contact with skin | |
| Skin corrosion/irritation, category 1B | H314鈥擟auses severe skin burns and eye damage |  |
| Skin sensitization, category 1 | H317鈥擬ay cause an allergic skin reaction |  |
| Serious eye damage/eye irritation, category 1 | H318鈥擟auses serious eye damage | |
| Acute toxicity, inhalation, category 2 | H330鈥擣atal if inhaled | |
| Respiratory sensitization, category 1 | H334鈥擬ay cause allergy or asthma symptoms or breathing difficulties if inhaled |  |
| Specific target organ toxicity, single exposure, respiratory tract irritation, category 3 | H335鈥擬ay cause respiratory irritation | |
| Specific target organ toxicity, repeated exposure, category 2 | H373鈥擟auses damage to organs through prolonged or repeated exposure: liver, thyroid gland, digestive tract, kidney, bladder | |
| Short-term (acute) aquatic hazard, category 1 | H400鈥擵ery toxic to aquatic life |  |
| Long-term (chronic) aquatic hazard, category 1 | H410鈥擵ery toxic to aquatic life with long-lasting effects | |
*Compilation of multiple safety data sheets. The greatest reported hazard is shown for each hazard class.
**Globally Harmonized System (GHS) of Classification and Labeling of Chemicals聽.
Molecule in the News
Since the 1985 discovery of all-carbon buckminsterfullerene1 (C60), chemists have been intrigued with making a non-carbon 鈥渟occer ball鈥� analogue. Some have been prepared that had to be stabilized by external ligands; but last November, a stand-alone all-metal fullerene was reported.
Zhong-Ming Sung at Nankai University (Tianjin, China) and colleagues at universities in China, Chile, and Germany 2, a nearly spherical structure with the 32 gold and antimony atoms forming the 鈥渂all鈥� and the lone potassium atom encapsulated in the center. The counterion is the potassium complex [K(2.2.2)cryptand]+ 3.
The researchers prepared [K@Au12Sb20]5鈭� via a reaction between the Zintl phase K8SnSb44 and the gold complex Au(PPh3)Me5 in ethylenediamine solution. The presence of [2.2.2]cryptand6 promoted the reaction and supplied the chelating agent for the counterion. After a 5-day incubation period at 10 掳C, black crystals were obtained that were confirmed by X-ray crystallography to contain the fullerene-like structure, a combination of .
1. CAS Reg. No. 99685-96-8.
2. CAS Reg. No. 3030175-02-8, representing a generic molecule with the empirical formula Au12KSb20.
3. CAS Reg. No. 61624-59-7.
4. CAS Reg. No. 3030175-58-4.
5. CAS Reg. No. 23108-72-7.
6. CAS Reg. No. 23978-09-8.
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Allyl isothiocyanate聽
fast facts
| CAS Reg. No. | 57-06-7 |
| CA Index Name | 1-Propene, 3-isothiocyanato- |
| Empirical formula | C4H5NS |
| Molar mass | 99.16 g/mol |
| Appearance | Colorless to pale yellow oily liquid |
| Boiling point | 150鈥�151 掳C |
| Water solubility | 2 g/L (20 掳C) |
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