Michler's ketone

From Wikipedia, the free encyclopedia
Jump to navigation Jump to search
Michler's ketone
Michler's ketone.png
Preferred IUPAC name
Other names
Michler ketone
Michler's Ketone
3D model (JSmol)
ECHA InfoCard 100.001.843
EC Number 202-027-5
Molar mass 268.360 g·mol−1
Appearance Colorless solid
Melting point 173 °C (343 °F; 446 K)
Safety data sheet External MSDS
not listed
Related compounds
Related compounds
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
☒N verify (what is ☑Y☒N ?)
Infobox references

Michler’s ketone is an organic compound with the formula of [(CH3)2NC6H4]2CO. This electron-rich derivative of benzophenone is an intermediate in the production of dyes and pigments, for example Methyl violet. It is also used as a photosensitizer.[1] It is named after the German chemist Wilhelm Michler.


The ketone is prepared today as it was originally by Michler using the Friedel-Crafts acylation of dimethylaniline (C6H5NMe2) using phosgene (COCl2) or equivalent reagents such as triphosgene (Me = methyl):[2]

COCl2 + 2 C6H5NMe2 → (Me2NC6H4)2CO + 2 HCl

The related tetraethyl compound (Et2NC6H4)2CO, also a precursor to dyes, is prepared similarly.


Michler’s ketone is an intermediate in the synthesis of dyes and pigments for paper, textiles, and leather. Condensation with various aniline derivatives gives several of the dyes called methyl violet, such as crystal violet.

Condensation of Michler's ketone with N-phenyl-1-naphthylamine gives the dye Victoria Blue B (CAS#2580-56-5, CI Basic Blue 26), which is used for coloring paper and producing pastes and inks for ballpoint pens.

Michler’s ketone is commonly used as an additive in dyes and pigments as a sensitizer for photoreactions because of its absorption properties. Michler’s ketone is an effective sensitizer provided energy transfer is exothermic and the concentration of the acceptor is sufficiently high to quench the photoreaction of Michler’s ketone with itself. Specifically Michler’s ketone absorbs intensely at 366 nm and effectively sensitizes photochemical reactions such as the dimerization of butadiene to give 1,2-divinylcyclobutane.[3]

Related compounds[edit]

p-Dimethylaminobenzophenone is related to Michler's ketone, but with only one amine.[4] Auramine O, a dye, is a salt of the iminium cation [(CH3)2NC6H4]2CNH2+. Michler's thione, [(CH3)2NC6H4]2CS, is prepared by treatment of Michler's ketone with hydrogen sulfide in the presence of acid or sulfideing auramine O.[5]


  1. ^ Kan, Robert O. (1966). Organic Photochemistry. New York: McGraw-Hill.
  2. ^ W. Michler (1876). "Synthese aromatischer Ketone mittelst Chlorkohlenoxyd". Berichte der deutschen chemischen Gesellschaft. 9: 716–718. doi:10.1002/cber.187600901218.
  3. ^ Charles D. DeBoer, Nicholas J. Turro, and George S. Hammond (1973). "cis- and trans-1,2-Divinylcyclobutane". Organic Syntheses.CS1 maint: Multiple names: authors list (link); Collective Volume, 5, p. 528
  4. ^ Hurd, Charles D.; Webb, Carl N. (1925). "p-Dimethylaminobenzophenone". 7: 24. doi:10.15227/orgsyn.007.0024.
  5. ^ Elofson, R. M.; Baker, Leslie A.; Gadallah, F. F.; Sikstrom, R. A. (1964). "The Preparation of Thiones in the Presence of Anhydrous Hydrogen Fluoride". The Journal of Organic Chemistry. 29 (6): 1355. doi:10.1021/jo01029a020.