Methyl violet properties

Purple Pigments. Methyl violet is the most commonly used purple pigment. It is also widely used for toning black inks. In packaging, although very expensive, Carbazole and Vat violets are used where permanence and resistance properties are needed. 

Certain of these indicators will again be considered by way of illustration of desirable properties. Methyl violet is green in 0.05 N hydrochloric acid, but the color fades appreciably even in fifteen minutes and disappears entirely after a longer interval. Evidently methyl violet can not be recommended for pH determinations, and cresol red or thymol blue must be used in its stead. In order to obtain stable acid solutions (red) of the latter indicators, no more than 0.1 c.c. of 0.1% solution should be used... 

The analytical methods proposed for acesulfame-K, cyciamate, and saccharin determination in foods, drinks, dietary products, and pharmaceuticals can be grouped into methods for the determination of an individual artificial sweetener [21-27] and multianalyte approaches [28-38], sometimes also including other sweeteners and/or other food additives, such as colorants or preservatives [39-43]. High-performance liquid chromatography (HPLC) is the most frequently used technique for the determination of these sweeteners, and this is selected by international standard methods because of its multianalyte capability, compatibility with the physicochemical properties of sweeteners, high sensitivity, and robustness [44-47]. However, cyciamate requires chemical derivatization to make it detectable by the most commonly employed UV-absorption detector due to a lack of a chromophore, by conversion to dichlorohexylamine for UV detection or to a fluorescence derivative for fluorimetric detection. Another alternative for cyciamate detection is the postcolumn ion-pair extraction where the eluted sweetener is mixed with an appropriate dye (methyl violet or crystal violet), being detected by visible absorption. Furthermore, cyciamate can be detected directly by refractive index [4]. For this, few HPLC methods for the concurrent determination of these sweeteners exist and... 

It is certain that methylene blue is the tetramethyl derivative of Lauth s violet, although it cannot be obtained by direct methyl-ation of the latter. Its constitution is analogous to that of tetramethylindamine. Like this, it contains a pentavalent nitrogen atom, which is in combination with two methyl groups and an hydroxyl or acid radical. The hydrochloride has the constitution expressed at the head of the section. The properties of the base of methylene blue are those of an ammonium base, and this agrees with the above conception of its constitution. The base is not easily separated from its salts. It is best obtained by decomposition of the hydrochloride with silver oxide, and has pi obably the formula CieHisNsSOH. It dissolves easily in water with a blue colour. 

CAS 4129-84-4 EINECS/ELINCS 223-942-6 Synonyms Acid violet 17, sodium salt Benzenemethanaminium, N-(4-((4-(diethylamino) phenyl) (4-(ethyl ((3-sulfophenyl) methyl) amino) phenyl) methylene)-2,5-cyclohexadien-1-ylidene)-N-ethyl-3-sulfo-, hydroxide, inner salt, sodium salt Cl 42650 Food violet 1 Violet BNP Classification Azobenzene Empirical C4iH46N3NaOsS2 Properties M.w. 762.93 Toxicology TSCA listed Uses Dye for wool, silk, paper, soap, and inks Manuf./Distrib. Aldrich http //www.sigma-aidrich.com, Anar Int l. http //www.anarchem.com, Fluka http //WWW.sigma-aidrich.com. Sigma... 

Ethyl-substituted aniline (31c) produces polymers with similar properties as the methyl-substituted polymers except that the films switch from green to blue on oxidation rather than blue to violet [123— 125]. Substitution with bulky alkyl and aryl groups such as 2,5-di-tcrt-butylaniline, 2,6-diethylaniline, 2-benzylaniline, and 2-propylaniline does not produce polymer films [121,124]. This can be attributed to the increased steric hindrance by the bulky alkyl groups which prevent formation of head-to-tail couplings during polymerization. 

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