Blanc chloromethylation
The Blanc chloromethylation is the chemical reaction of aromatic rings with formaldehyde and hydrogen chloride catalyzed by zinc chloride to form chloromethyl arenes. The reaction was discovered by Gustave Louis Blanc (1872-1927) in 1923.[1][2][3] The reaction should be performed with care, as (like most chloromethylation reactions) it produces highly carcinogenic bis(chloromethyl) ether as a by-product.
Mechanism
The reaction is carried out under acidic conditions and with a ZnCl2 catalyst. These conditions protonate the formaldehyde carbonyl making the carbon much more electrophilic. The aldehyde is then attacked by the aromatic pi-electrons, followed by rearomatization of the aromatic ring. The benzyl alcohol thus formed is quickly converted to the chloride under the reaction conditions.
Although the reaction is an efficient means of introducing a chloromethyl group, the production of small amounts of highly carcinogenic bis(chloromethyl) ether is a disadvantage.
See also
References
- ↑ Gustave Louis Blanc Bull. Soc. Chim. France 1923, 33, 313
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
<templatestyles src="Asbox/styles.css"></templatestyles>
 |
This chemical reaction article is a stub. You can help Wikipedia by expanding it. |
