Michler's ketone is an

organic compound In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. The ...

with the formula of CH₃)₂NC₆H₄sub>2CO. This electron-rich derivative of

benzophenone Benzophenone is the organic compound with the formula (C6H5)2CO, generally abbreviated Ph2CO. It is a white solid that is soluble in organic solvents. Benzophenone is a widely used building block in organic chemistry, being the parent diarylket ...

is an intermediate in the production of dyes and pigments, for example

Methyl violet Methyl violet is a family of organic compounds that are mainly used as dyes. Depending on the number of attached methyl groups, the color of the dye can be altered. Its main use is as a purple dye for textiles and to give deep violet colors in p ...

. It is also used as a

photosensitizer Photosensitizers produce a physicochemical change in a neighboring molecule by either donating an electron to the substrate or by abstracting a hydrogen atom from the substrate. At the end of this process, the photosensitizer eventually returns to ...

. It is named after the German chemist

Wilhelm Michler Wilhelm Michler (27 December 1846 – 27 November 1889) was a German chemist. He studied under Hermann von Fehling and Victor Meyer in Stuttgart and followed Meyer to the ETH Zurich in 1871. Michler became professor at the ETH Zurich in 1878. H ...

Synthesis

The ketone is prepared today as it was originally by Michler using the Friedel-Crafts

acylation In chemistry, acylation (or alkanoylation) is the chemical reaction in which an acyl group () is added to a compound. The compound providing the acyl group is called the acylating agent. Because they form a strong electrophile when treated with ...

dimethylaniline ''N'',''N''-Dimethylaniline (DMA) is an organic chemical compound, a substituted derivative of aniline. It consists of a tertiary amine, featuring dimethylamino group attached to a phenyl group. This oily liquid is colourless when pure, but comm ...

(C₆H₅NMe₂) using

phosgene Phosgene is the organic chemical compound with the formula COCl2. It is a toxic, colorless gas; in low concentrations, its musty odor resembles that of freshly cut hay or grass. Phosgene is a valued and important industrial building block, espe ...

(COCl₂) or equivalent reagents such as

triphosgene Triphosgene (bis(trichloromethyl) carbonate (BTC) is a chemical compound with the formula OC(OCCl3)2. It is used as a solid substitute for phosgene, which is a gas. Triphosgene is stable up to 200 °C. Triphosgene is used in a variety of halogena ...

:COCl₂ + 2 C₆H₅NMe₂ → (Me₂NC₆H₄)₂CO + 2 HCl → salt 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 Methyl violet is a family of organic compounds that are mainly used as dyes. Depending on the number of attached methyl groups, the color of the dye can be altered. Its main use is as a purple dye for textiles and to give deep violet colors in p ...

, such as

crystal violet Crystal violet or gentian violet, also known as methyl violet 10B or hexamethyl pararosaniline chloride, is a triarylmethane dye used as a histological stain and in Gram's method of classifying bacteria. Crystal violet has antibacterial, antif ...

. Condensation of Michler's ketone with ''N''-phenyl-1-naphthylamine gives the dye

Victoria Blue B Victoria most commonly refers to: * Victoria (Australia), a state of the Commonwealth of Australia * Victoria, British Columbia, provincial capital of British Columbia, Canada * Victoria (mythology), Roman goddess of Victory * Victoria, Seychelle ...

(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 In thermodynamics, an exothermic process () is a thermodynamic process or reaction that releases energy from the system to its surroundings, usually in the form of heat, but also in a form of light (e.g. a spark, flame, or flash), electricity (e ...

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 1,3-Butadiene () is the organic compound with the formula (CH2=CH)2. It is a colorless gas that is easily condensed to a liquid. It is important industrially as a precursor to synthetic rubber. The molecule can be viewed as the union of two viny ...

to give 1,2-divinylcyclobutane.

Related compounds

''p''-Dimethylaminobenzophenone is related to Michler's ketone, but with only one amine.

Auramine O Auramine O is a diarylmethane dye used as a fluorescent stain. In its pure form, Auramine O appears as yellow needle crystals. It is insoluble in water and soluble in ethanol and DMSO. Auramine O can be used to stain acid-fast bacteria (e.g. ' ...

, a dye, is a salt of the iminium cation CH₃)₂NC₆H₄sub>2CNH₂⁺. Michler's thione, CH₃)₂NC₆H₄sub>2CS, is prepared by treatment of Michler's ketone with

hydrogen sulfide Hydrogen sulfide is a chemical compound with the formula . It is a colorless chalcogen-hydride gas, and is poisonous, corrosive, and flammable, with trace amounts in ambient atmosphere having a characteristic foul odor of rotten eggs. The unde ...

in the presence of acid or sulfideing auramine O.{{cite journal , doi = 10.1021/jo01029a020 , title = The Preparation of Thiones in the Presence of Anhydrous Hydrogen Fluoride , year = 1964 , last1 = Elofson , first1 = R. M. , last2 = Baker , first2 = Leslie A. , last3 = Gadallah , first3 = F. F. , last4 = Sikstrom , first4 = R. A. , journal = The Journal of Organic Chemistry , volume = 29 , issue = 6 , pages = 1355 Hydride reduction of Michler's ketone gives

4,4'-bis(dimethylamino)benzhydrol 4,4′-Bis(dimethylamino)benzhydrol is an organic compound with the formula (Me2NC6H4)2CH(OH), where Me is methyl. It is a white solid that is soluble is a variety of organic solvents. The compound is notable as the reduced derivative of Michle ...

References

Printing Benzophenones Anilines Dimethylamino compounds