Methyl Violet

An older process, now abandoned, possesses interest from a theoretical standpoint. In this case no chlorine compound was used, the mixture consisting of dimethylaniline, copper sulphate, acetic acid, and sand. The violet is precipitated from the solution of the melt as sulphate by sodium sulphate. The absence of chlorine prevents the formation of the insoluble double chloride, and the reduced copper compound is got rid of as insoluble suboxide. 

The rdle played by the phenol in the modern process of manufacture has not been explained, but it is certain that its presence considerably increases the yield of the dyestuff. 

Methyl violet is produced by action of other oxidising agents on dimethylaniline, such as iodine and chloranil. According to Brunner and Brandenburg bromine acts on dimethylaniline, forming a brominated methyl violet [21]. On the other hand, the dyestuff is not produced by oxidation of dimethylaniline in acid solution, with lead peroxide, manganese dioxide, or chromic acid. 

As yet, the chemistry of the methyl-violet process is little understood. According to E. and O. Fischer [12], a methyl group is partly oxidised, and the formic acid produced thereby serves to link the benzene nuclei together, and to supply the necessary methane-carbon atom. As, however, the formation of 

In fact 0. Fischer and Koerner have obtained hexamethylpara-leucaniline quantitatively by action of the methyl ether of ortho-formic acid on dimethylaniline [22]. The violet from dimethyl-aniline and chloranil is apparently identical with the ordinary one obtained by the copper process [23]. 

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Methyl violet (indicator) dissolve 0.25 g in 100 mL water, pH range blue 1.5-3.2 violet. 

In this experiment the goal is to mix solutions of 1 M HCl and 20-ppm methyl violet to give the maximum absorbance at a wavelength of 425 nm (corresponding to a maximum concentration for the acid form of methyl violet). A variable-size simplex optimization is used to find the optimum mixture. 

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. 

Pigment Violet 3 [1325-82-2] 42535 2 triarylcarbonium PTMA salt salt formation between Methyl Violet and phosphotungstomolybdic acid... 

Methyl violet [8004-87-3] Cl Basic Violet 1 (17), is made by the air oxidation of dimethyl aniline in the presence of salt, phenol, and a copper sulfate catalyst. Initially, some of the dimethyl aniline is oxidized to formaldehyde and /V-methyl aniline under those conditions. The formaldehyde then reacts with dimethyl aniline to produce N,N,]S7,1S7-tetramethyldiaminodiphenylmethane, which is oxidized to Michler s hydrol [119-58-4]. The hydrol condenses with... 

V-methyl aniline formed in the initial step to give the leuco base of methyl violet. Treatment with aqueous acid produces the dye. Because Michler s hydrol may also react with dimethyl aniline instead of the /V-methyl aniline to give crystal violet, commercial-grade methyl violet is usually a mixture. A cobalt complex has converted 4,T-dimethylaminodipheny1methane and dimethyl aniline in the presence of atmospheric oxygen to crystal violet in one step (50). 

Stability. Heat stabihty is determined by measuring the time required for a specific amount of CN, held at 134.5°C, to decompose and discolor methyl violet test paper (75). 

The results of the complexation study of Cu(II), Pb(II), Zn(II), Fe(III), Hg(II), Cd(II), Sn(IV), Zr(IV), Ti(IV) with arsenazo III, sulfonazo III, SPADNS, Eriochrome T, Acid Chrome Dai k Blue, Xylenol Orange, Methyl Thymol Blue, Pyrocatechol Violet, Chrome Azurol S, Eriochrome Cyanin R, Basic Blue K, Methyl Violet, Brilliant Green, Rhodamine C and Astraphoxin in solid phase. The obtained data ai e used for the working out of a new method of metal determination. 

Zone refining purified naphthalene from anthracene, 2,4-dinitrophenylhydrazine, methyl violet, benzoic acid, methyl red, chrysene, pentacene and indoline. 

Add I c.c. of the sulphonic chloride to 2 c.c. aniline, stir up well, add water, and acidify with a few diops of concentrated HCl (methyl violet paper). Filter, wash, and crystallise the benzenesulphonanilide from spirit, C(jH3SO,Cl- -NH,C(,H- -= QHoSO NHC.H -l-HCl. 

In a 30 minute test the results obtained should not differ by more than 1 minute using different lots of paper. On being exposed to nitric oxide fumes, these papers slowly turn green, followed by a salmon pink coloration Methyl Violet Paper Test (Field Test for Pro pint Powders). This method of testing proplnts using 0.1N methyl violet paper directly in the containers in which the powder is stored, was developed at Picatinny Arsenal in 1928—29 (Refs 1 2), and was adopted by the Ordnance Dept to replace the Observation Test about 1931... 

Note The Observation Test was intended to detect the initial decompn of propint, and was conducted at ail depots and posts where powder was stored. A 6oz sample of each lot of powder with a strip of methyl violet test paper was placed in a glass-stoppered bottle, with the paper not in contact with the powder. The test was conducted in the magazine in which the proplnt under test was stored. Bleaching of the test paper was taken as an indication that the powder had started to de-... 

In cases where a lot of proplnt has successfully passed the one-year exposure to methyl violet paper, only a 3% inspection of the exposed test strips need to be made thereafter until such inspection indicates progressive deterioration of the proplnt or other nonstandard condition, at which time 100% inspection and test of the lot under suspicion will be resumed It is considered desirable that succeeding annual inspections include at least 1/3 of the containers included in the original 3% inspection as outlined above. In this manner, such containers may be considered as a basic comparative control with reference to the balance of the lot under test... 

If the proplnt is double-base, it has been observed that even the most stable propints bleach methyl violet paper in much shorter periods than one year. Investigations conducted by P.F. Macy at Picatinny Arsenal (Ref 4) showed that diphenylamine-stabilized doublebase proplnts in service storage at about 30°, may be considered of satisfactory stability if they do not cause complete bleaching of 0.1 N methyl violet paper in one month or less. Such proplnts always show satisfactory stability when subjected to the 65.5° Surveillance Test. It was observed at the same time, that double-base proplnts which had deteriorated, but were not yet hazardous, took from 11 to 24 days to bleach methyl violet paper at 30°... 

Later tests at Picatinny Arsenal revealed that methyl violet paper very often faded in shorter time periods than described above, even for perfectly stable powders, as detd by the 65.5°... 

This applied particularly to double-base propints, although some single-base propints also gave erratic results. For these reasons, work was undertaken at Picatinny Arsenal to find an indicator that would be more reliable than methyl violet. About 60 commercially available dyes were examined by S. Helf (Ref 5) in exptl indicator paper tests, of which only three were found to be superior to methyl violet benzoazurine, trypan red and ethyl violet. Laboratory and surveillance testing showed that papers prepd with a 0.1% soln of benzoazurine did not change in color after one year when used with stable double-base propint, while methyl violet paper was bleached in nearly every case. The other two indicators mentioned above, trypan red and ethyl violet, were not as satisfactory as benzoazurine, although they were better than methyl violet. 

On the other hand, when paper strips with benzoazurine, trypan red or ethyl violet were exposed to unstable double-base propint, or to nitrogen oxide fumes prepd in the lab, all of the papers either bleached or faded, as did the methyl violet paper... 

Methyl Violet Paper Test for Double-Base Powders , PATR 1652 (1947) 5) S. Helf,... 

The polyester is stable in storage at RT. The thermal stability at 65.5° using a 1.3g sample and Kl-Starch indicator paper is failure after 100 mins (Ref NC, 10 min, no color) at 134,5 using a 2.5g sample and Methyl violet paper, failure is shown after SO mins (Ref NC, 30 mins, no color)... 

The polymer s Qc is 2996cal/g at 25° (Ref liq H20 at 25°). Impact sensy using the BM machine with a 2kg wt is 100cm at the 50% point (RDX, 28cm). Thermal stability at 65.5° using KI-Starch paper is 23 min (Ref NC, 10 mins, no color) thermal stability at 134.5° using Methyl violet paper shows no failure in 5 hrs (Ref NC, 30 mins, no color)... 

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