Methyl violet 6B (Pentamethylparosanilinium chloride, 4-[[4-(dimethylamino)phenyl]-(4-methyliminocyclohexa-2,5-dien-1-ylidene)methyl]-N,N-dimethylaniline·hydrochloride) is a violet triarylmethane dye from the group of cationic dyes and an essential component of C.I. Basic Violet 1 (trivial name methyl violet). The compound is sometimes equated with methyl violet in the literature.

Methyl violet 6B
Methyl violet 6B
Names
IUPAC name
4-[[4-(dimethylamino)phenyl]-(4-methyliminocyclohexa-2,5-dien-1-ylidene)methyl]-N,N-dimethylaniline·hydrochloride
Other names
  • Gentian violet B,
  • Methylrosanilinium chloride,
  • Pentamethylparosanilinium chloride,
  • Basic Violet 3,
Identifiers
3D model (JSmol)
ChEMBL
ChemSpider
ECHA InfoCard 100.009.130 Edit this at Wikidata
EC Number
  • 610-776-8
UNII
  • InChI=1S/C24H27N3.ClH/c1-25-21-12-6-18(7-13-21)24(19-8-14-22(15-9-19)26(2)3)20-10-16-23(17-11-20)27(4)5;/h6-17H,1-5H3;1H ☒N
    Key: JFTBTTPUYRGXDG-UHFFFAOYSA-N ☒N
  • CN=C1C=CC(=C(C2=CC=C(C=C2)N(C)C)C3=CC=C(C=C3)N(C)C)C=C1.Cl
Properties
C24H28N3Cl
Appearance Green to dark-green powder[1]
Melting point 137 °C (279 °F; 410 K) decomposes[1]
Soluble in water, ethanol, insoluble in xylene[1]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Methyl violets are mixtures of tetramethyl (2B), pentamethyl (6B) and hexamethyl (10B) pararosanilins.[2]

Synthesis

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To produce methyl violet 6B, N,N-dimethylaniline is oxidized with atmospheric oxygen and copper sulfate as a catalyst, using phenol and large amounts of salt as a diluent. The central carbon atom of the dye is provided by the oxidation of a methyl group of N,N-dimethylaniline to formaldehyde.[3] In this process, a reaction product is obtained that contains the tetra- to hexamethylated compounds in addition to the pentamethylated compound.

 
Synthesis of Methyl violet 6B

References

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  1. ^ a b c R. W. Sabnis (29 March 2010). Handbook of Biological Dyes and Stains: Synthesis and Industrial Applications. John Wiley and Sons. pp. 309–. ISBN 978-0-470-40753-0. Retrieved 27 June 2011.
  2. ^ C. Bouasla, M. E. H. Samar, F, Ismail: Degradation of methyl violet 6B dye by the Fenton process. In: Desalination. 254.1–3, 2010, S. 35–41, doi:10.1016/j.desal.2009.12.017.
  3. ^ K. Venkataraman (1952), The Chemistry of Synthetic Dyes, vol. II, New York, London: Academic Press, p. 719