is an organic
compound with the formula of [(CH3
CO. 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 sensitizer
. 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
using phosgene or equivalent reagents such as triphosgene
(Me = methyl):
- COCl2 + 2 C6H5NMe2 → (Me2NC6H4)2CO + 2 HCl
Michler’s ketone is an intermediate in the synthesis of dyes and pigments for paper, textiles, and leather. Ethyl violet (CAS#2390-59-2, CI Basic Violet 4) is prepared by the condensation
Michler’s ketone with diethylaniline in the presence of phosphorus oxychloride
- (Me2NC6H4)2CO + C6H5NEt2 + HCl → [(Me2NC6H4)2C=C6H4NEt2]+Cl- + H2O
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.