What molecule am I?
Chlormequat, aka chlorocholine, is a cationic quaternary ammonium compound. As its chloride salt (see images), it has been an article of commerce for �60 years.
In 1927, Austrian chemists Sigmund Fränkel* and Klara Nussbaum synthesized what they called “choline dichloride� via the reaction of trimethylamine1 and 1,2-dichloroethane2. In the 1950s, Nathan E. Tolbert at Michigan State University (East Lansing) was experimenting with (2-chloroethyl)trimethylammonium chloride (his name for the salt) as a (PGR). He first tried it on wheat; and in 1960, he reported his findings that the treated plants had shorter, thicker stems; broader, greener leaves; and more uniform growth than the controls.
The same year, Tolbert and his colleague Sylvan H. Wittwer published four additional articles that described the effects, mostly positive, of (2-chloroethyl)trimethylammonium chloride on the growth of , , again, and chrysanthemums and poinsettias.
Since these early studies, chlormequat chloride has been widely used as a PGR even though it was not registered with the US Environmental Protection Agency until 2022. That year, EPA classified it as a “� for use on ornamental plants. The following year, the agency proposed allowing it to be .
Among recent reports of the use of chlormequat chloride in agriculture, Kimber Wise, Sukhpret Singh, and Jamie Selby-Pham* at three Australian institutions described the use of a complex of the compound with paclobutrazol3, another PGR, to supplement the use of fertilizer on marijuana (Cannabis sativa). The researchers found that application of the combination compared with control plants—a beneficial result. According to the authors, “application of these PGRs in combination may be utilized to restrict cannabis height without compromising yield within commercial cultivation.�
1. CAS Reg. No. 75-50-3.
2. CAS Reg. No. 107-06-2.
3. CAS Reg. No. 76738-62-0.
Chlormequat chloride hazard information*
| Hazard class** | GHS code and hazard statement | |
|---|---|---|
| Acute toxicity, oral, category 4 | H302—Harmful if swallowed |  |
| Acute toxicity, dermal, category 3 | H311—Toxic in contact with skin |  |
| Eye irritation, category 2B | H320—Causes eye irritation | |
| Specific target organ toxicity, single exposure, category 2 | H371—May cause damage to organs (systemic toxicity) |  |
| Short-term (acute) aquatic hazard, category 3 | H402—Harmful to aquatic life | |
*Compilation of multiple safety data sheets.
**Globally Harmonized System (GHS) of Classification and Labeling of Chemicals. .
MOTW updates
1,4-Dioxane1, the Molecule of the Week for August 5, 2019, is a common solvent that has come under scrutiny as a suspected carcinogen and a drinking water and groundwater contaminant. In recent years, dioxane has been of concern as a contaminant in ingredients used to formulate household products. A 2022 New York State law restricts the concentration of dioxane in cleaning and personal care products to 1 ppm and in cosmetics to 10 ppm. But some jurisdictions believe that regulations should be even tighter; in one case, regulators are proposing a in consumer products rather than the product as a whole.
Methylene blue2 was the Molecule of the Week for June 14, 2011. It is an organic dye that dates back to 1876 for use on cotton fabrics. It has since been used for other purposes, such as a medical stain, an antifungal agent, a redox reaction indicator, and a photosensitizer for generating singlet oxygen. Last month, Jan A. Mennigen and co-workers at the University of Ottawa reported on the effects of methylene blue on zebrafish (Danio rerio), which are widely used as model organisms in biological research. Zebrafish embryos are typically reared in media containing methylene blue as an antifungal; but the researchers found that the dye can . The authors conclude that the use of methylene blue in zebrafish research should be reconsidered.
1. CAS Reg. No. 123-91-1.
2. CAS Reg. No. 61-73-4.
This molecule was suggested by a reader. We present almost all of the molecules suggested by our readers. If you have a molecule you would like us to consider, please send us a message. And thank you for your interest in Molecule of the Week! —Ed.
°ä³ó±ô´Ç°ù³¾±ð±ç³Ü²¹³ÙÌý³¦³ó±ô´Ç°ù¾±»å±ðÌý
fast facts
| CAS Reg. No. | 999-81-5 |
| SciFindern name | Ethanaminium, 2-chloro-N,N,N- trimethyl-, chloride |
| Empirical formula | C5H13Cl2N |
| Molar mass | 158.07 g/mol |
| Appearance | Hygroscopic white crystals |
| Melting point | 245 ºC (dec.) |
| Water solubility | 740 g/L (20 ºC) |
, the most authoritative and comprehensive source for chemical information.
Molecule of the Week needs your suggestions!
If your favorite molecule is not in our archive, please send us a message. The molecule can be notable for its current or historical importance or for any quirky reason. Thank you!
Stay Ahead of the Chemistry Curve
Learn how ACS can help you stay ahead in the world of chemistry.
