Crystal Violet Chloride

Crystal Violet Chloride (Gentian vioiet, V-4[bis[4-(dimethyiaminophenyi)methyiene]-2,5-cyciohexadien-l-yiidene]-V-methyimethaninium chioride [548-62-9] M 408.0, pK 9.36. 

CRYSTAL VIOLET AON CRYSTAL VIOLET 6B CRYSTAL VIOLET lOB CRYSTAL VIOLET BASE CRYSTAL VIOLET 5BO CRYSTAL VIOLET 6BO CRYSTAL VIOLET BP CRYSTAL TOLETBPC CRYSTAL VIOLET O D CRYSTAL VIOLET CHLORIDE O CRYSTAL VIOLET EXTRA PURE CRYSTAL VIOLET EXTRA PURE APN CRYSTAL VIOLET EXTRA PURE APNX CRYSTAL VIOLET FN CRYSTAL VIOLET HL2 CRYSTAL VIOLET PURE DSC CRYSTAL VIOLET PURE DSC BRILLIANT CRYSTAL VIOLET SS... 

Ketone condensation, a third method of into JV,N-dimethylaniline, is condensed with manufacture of triphenylmethane dyes, is JV,JV-dimethylaniline using phosphorus oxy-illustrated with Basic Violet 3 (Crystal Violet), chloride. A carbinol is formed, which is Michler s Ketone, made by passing phosgene converted to the dye with hydrochloric acid. 

Acetyl chloride frequently contains 1—2% by weight of acetic acid or hydrochloric acid. Phosphoms or sulfur-containing acids may also be present in the commercial material. A simple test for purity involves addition of a few drops of Crystal Violet solution in CHCl. Pure acetyl chloride will retain the color for as long as 10 min, but hydrochloric, sulfuric, or acetic acid will cause the solution to become first green, then yellow (34). 

The first triaryknethane dyes were synthesized on a strictiy empirical basis in the late 1850s an example is fuchsine, which was prepared from the reaction of vinyl chloride with aniline. Thek stmctural relationship to triphenylmethane was estabHshed by Otto and Fmil Fischer (5) with the identification of pararosaniline [569-61-9] as 4,4, 4 -triaminotriphenyknethane and the stmctural elucidation of fuchsine. Several different stmctures have been assigned to the triaryknethane dyes (6—8), but none accounts precisely for the observed spectral characteristics. The triaryknethane dyes are therefore generally considered to be resonance hybrids. However, for convenience, usually only one hybrid is indicated, as shown for crystal violet [548-62-9] Cl Basic Violet 3 (1), for which = 589 nm. 

The manufacture of crystal violet (1), however, is a special case which does not involve the isolation of the intermediate Michler s ketone (Fig. 3). Thus, phosgene is treated with excess dimethyl aniline in the presence of zinc chloride. Under these conditions, the highly reactive intermediate "ketone dichloride" is formed in good yield this intermediate further condenses with another mole of dimethyl aniline to give the dye. 

Crotonic acid, esterification with sec-butyl alcohol, 41, 60 Crystal Violet, from condensation of oxalyl chloride with dimethyl-aniline, 41, 2-4... 

The oxidation of N, A-dimethylaniline by aerated, ethanolic cupric chloride to give a mixture of products including methyl and crystal violets is simple second-order when an excess of amine is used Presumably Cu(I) is re-oxidised by dissolved oxygen, for otherwise the observed linearity of log [residual amine] versus time plots would not be found as Cu(II) disappears. Under nitrogen the kinetics are complex, but a new optical absorption (472 and 1007 nm) appears immediately on mixing the reactants. This absorption decays whilst a new one at 740 nm develops. The latter absorption originates from a 1 1 complex formulated... 

POCl, + SHjO — H3PO4 + 3HC1 Pass steam into the mixture (Fig. II, 40, 1) until no more drops of unattacked dimethylaniline pass over into the receiver. Allow to cool and filter the reddish precipitate of the colour base at the pump and wash it with water. Transfer the precipitate to a large beaker and boO it with a mixture of 5 ml. of concentrated hydrochloric acid and 1 litre of water. Filter the hot solution and set the filtrate aside for crystallisation to take place. Treat the residue with successive portions of fresh dilute hydrochloric acid until it has almost entirely dissolved. On cooling and standing, the crystal violet separates in green crystals filter these with suction. Treat the combined filtrates, whilst stirring, with finely-powdered sodium chloride until precipitation is complete and the liquid is just saturated collect the precipitate in a filter. The crystal violet may be recrystallised from a little water, and dried upon filter paper in the air. The yield is 12 g. 

The phthalide 25, obtainable by condensation of 4,4 -bisdimethyl-aminobenzophenone-2-carboxylic acid with 3-dimethylaminoacetanilide and subsequent hydrolysis, was diazotized in sulfuric acid and the resultant diazonium salt treated with copper powder to yield 26. However, better yields are reportedly obtained by carrying out ring closure of the diazonium salt in phosphoric acid.103 A further synthetic route has also been described in which phthalides undergo intramolecular cyclization in the presence of aluminum chloride and urea.104,105 Thus, Crystal Violet lactone (2) has been directly converted into phthalide 26.106... 

Tran [391,392] has reported ng detection of dyes on filter paper by SERS. Silver colloidal hydrosols stabilised by filter supports enhance the Raman scattering of adsorbed dyes. Typical detection limits are 500 pg (crystal violet), 7 ng (l,l,9-trimethyl-2,2 -cyanine perchlorate), 15 ng (3,3 -diethylthiacarbocyanine chloride) and 240 ng (methyl red) using a 3 mW He-Ne laser. 

Materials Required Methacholine chloride 0.4 g glacial acetic acid 50 ml mercuric acetate solution 10 ml 0.1 N perchloric acid and crystal violet solution. 

Crystal Violet, Gentian Violet N-[4-[Bis[4-dimethylamino)-phenyl]methylene]-2,5-cyclohexadien-1 -y lidine] -N-methyl-methan-aminium chloride... 

Cooling below —10° should be avoided because the reaction stops at that temperature and large amounts of oxalyl chloride accumulate in the flask. If this mixture is then allowed to come to room temperature, a vigorous reaction that may get out of control will take place. It is probable that, at reaction temperatures about 10°, the yield of 4,4,-bis(dimethylamino)benzil is less and some Crystal Violet is formed as an impurity, for it has been reported that aluminum chloride effects the conversion of N,N-dimetbylaniline and oxalyl chloride to Crystal Violet in 92-95% yield when the reaction is allowed to proceed without cooling.2... 

The last compound 4 4 -tetramethyl-di-amino-benzophenone is also known as Michler s ketone, and is an important intermediate in the preparation of dyestuffs of the fuchsine series, e.g., crystal violet. For the preparation of this ketone by treatment of dimethylaniline with carbon dioxide in presence of aluminium chloride, see E.P., 353464. 

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