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The dye can also be prepared by the condensation of formaldehyde and dimethylaniline to give a leuco dye: [3] [4] [7] CH 2 O + 3 C 6 H 5 N(CH 3) 2 → CH(C 6 H 4 N(CH 3) 2) 3 + H 2 O. Second, this colourless compound is oxidized to the coloured cationic form (hereafter with oxygen, but a typical oxidizing agent is manganese dioxide, MnO 2):
Methyl violet 2B (IUPAC name: 4,4′-((4-Iminocyclohexa-2,5-dien-1-ylidene)methylene)bis(N,N-dimethylaniline) monohydrochloride) is a green powder which is soluble in water and ethanol but not in xylene. It appears yellow in solution of low pH (approximately 0.15) and changes to violet with pH increasing toward 3.2. [3]
Azo violet (Magneson I; [1] p-nitrobenzeneazoresorcinol) is an azo compound with the chemical formula C 12 H 9 N 3 O 4. It is used commercially as a violet dye and experimentally as a pH indicator, appearing yellow below pH 11, and violet above pH 13. [2] It also turns deep blue in the presence of magnesium salt in a slightly alkaline, or basic ...
Methyl violet 2B (Tetramethylparosanilinium chloride, 4,4′-[(4-imino-2,5-cyclohexadien-1-yliden)methylen]bis(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 spectral colors from red to violet are divided by the notes of the musical scale, starting at D. The circle completes a full octave, from D to D. Newton's circle places red, at one end of the spectrum, next to violet, at the other. This reflects the fact that non-spectral purple colors are observed when red and violet light are mixed.
A U.S. soldier uses a VS-17 panel to signal an approaching helicopter during an exercise, 2015. The VS-17 is a signaling device used by military personnel to send signals to aircraft, [1] [2] and to mark improvised landing sites. [3] VS-17 panels (lower left corner) are used to mark a unimproved landing site for a C-130J Hercules, 2022