Crystal violet
| Names | |
|---|---|
| IUPAC name
4-{Bis[4-(dimethylamino)phenyl]methylidene}-N,N-dimethylcyclohexa-2,5-dien-1-iminium chloride
| |
| Other names
Aniline violet
Basic violet 3 Baszol Violet 57L Brilliant Violet 58 Gentian violet Hexamethyl-p-rosaniline chloride Methylrosanilide chloride Methyl Violet 10B Methyl Violet 10BNS Pyoktanin | |
| Properties | |
| C25H30ClN3 | |
| Molar mass | 407.99 g/mol |
| Appearance | Dark green or purple solid |
| Odor | Odorless |
| Density | 1.219 g/cm3[1] |
| Melting point | 202–204 °C (396–399 °F; 475–477 K) (decomposes)[2] |
| Boiling point | Decomposes |
| 3 g/100 ml | |
| Solubility in ethanol | Soluble in ethanol Slightly soluble in chloroform Insoluble in acetone, toluene, xylene |
| Vapor pressure | ~0 mmHg |
| Hazards | |
| Safety data sheet | Sigma-Aldrich |
| Lethal dose or concentration (LD, LC): | |
| LD50 (Median dose)
|
1,200 mg/kg (mouse, oral) 1,000 mg/kg (rat, oral) |
| Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
| Infobox references | |
Crystal violet or gentian violet, is a triarylmethane dye used as a histological stain and pH indicator.
The name "gentian violet" was originally used for a mixture of methyl pararosaniline dyes (methyl violet), but is now often considered a synonym for crystal violet. The name refers to its color, being like that of the petals of certain gentian flowers; it is not made from gentians or violets.
Contents
Properties
Chemical
The color of the dye depends on the acidity of the solution. At a pH of +1.0, the dye is green with absorption maxima at 420 nm and 620 nm, while in a strongly acidic solution (pH −1.0), the dye is yellow with an absorption maximum at 420 nm.
Physical
Crystal violet is a dark green or purple solid, slightly soluble in water.
Availability
Crystal violet can be bought from chemical suppliers or online.
Preparation
The original synthesis involves the reaction between dimethylaniline with phosgene to give 4,4′-bis(dimethylamino)benzophenone (Michler's ketone) as an intermediate. This was then reacted with additional dimethylaniline in the presence of phosphoryl chloride and hydrochloric acid to yield crystal violet.
Reaction of oxalyl chloride with dimethylaniline yields crystal violet. Anh. aluminium chloride is used as catalyst.[3]
Gentian violet can also be prepared by the condensation of formaldehyde and dimethylaniline to give an intermediary leuco dye, which is oxidized, using manganese dioxide to the colored cationic form, and then treated with HCl.
Reaction of dimethylaniline with para-dimethylaminobenzaldehyde, in the presence of aniline hydrochloride, under heating at 90 °C, under strong light, yields crystal violet. Yield is given as 86%.[4] The same reaction, can be used in a two-step process: in the first, the two compounds are refluxed in glacial acetic acid for 8 h at 100 °C, under inert atmosphere; in the second step, chloranil and sodium nitrite are added to the reaction mixture, and stirred at 50 °C for 12 h. Yield of this route is given as 80%.[5]
Projects
- pH indicator
- Histological stain
- Antibacterial, antifungal, and anthelmintic medication
- Make black inks
- Make marking blue for marking metals
- Develop fingerprints
Handling
Safety
Crystal violet has low toxicity. It has been shown to have antibacterial, antifungal, antihelminthic, antitrypanosomal, antiangiogenic, and antitumor properties.
Some studies show that it might cause cancer in rodents, but this is still debated.
Storage
In closed bottles, away from light an air.
Disposal
No special disposal is required. Can be destroyed with bleach and then poured down the drain.
References
- ↑ Berkman; Zocher; Zeitschrift fuer Physikalische Chemie, Stoechiometrie und Verwandtschaftslehre; vol. 124; (1926); p. 325
- ↑ Rudolf, Ondrej; Mrkvicka, Vladimir; Lycka, Antonin; Rouchal, Michal; Klasek, Antonin; Journal of Heterocyclic Chemistry; vol. 50; nb. SUPPL.1; (2013); p. E100-E110
- ↑ Postowski; ; vol. 4; p. 552; Chem. Zentralbl.; vol. 98; nb. II; (1927); p. 2183
- ↑ Guzmán-Lucero; Guzmán; Likhatchev; Martínez-Palou; Tetrahedron Letters; vol. 46; nb. 7; (2005); p. 1119 - 1122
- ↑ Kaur, Paramjit; Sareen, Divya; Singh, Kamaljit; Dalton Transactions; vol. 41; nb. 32; (2012); p. 9607 - 9610
