Michler's ketone

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Michler's Ketone
File:Michler's ketone.png
style="background: #F8EABA; text-align: center;" colspan="2" | Identifiers
CAS number 90-94-8
style="background: #F8EABA; text-align: center;" colspan="2" | Properties
Molecular formula C17H20N2O
Molar mass 268.36 g/mol
Appearance colorless solid
style="background: #F8EABA; text-align: center;" colspan="2" | Hazards
MSDS External MSDS
EU classification not listed
style="background: #F8EABA; text-align: center;" colspan="2" | Related compounds
Related compounds Benzophenone
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
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 sensitizer.[1] It is named after the German chemist Wilhelm Michler.

Synthesis

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

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

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

Uses

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]

References

  1. Kan, Robert O. "Organic Photochemistry" McGraw-Hill, New York, 1966.
  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", Org. Synth. ; Coll. Vol., 5: 528  Missing or empty |title= (help)
de:Michlers Keton

fr:Cétone de Michler ru:Кетон Михлера fi:4,4’-bis(dimetyyliamino)bentsofenoni