Violet, Acid Crystal

While the student is being educated in preparative work it is necessary for him to acquire some knowledge of the incessant progress in the methods of organic chemistry and at the same time to become familiar with the most recent results of research work. For these reasons a series of changes had to be made when this new edition was prepared. In order not to increase the bulk of the book these objects have been attained by sacrificing examples (e.g. lino-lenic acid, crystal violet, Gattermann-Koch aldehyde synthesis) with which, from this point of view, it seemed possible to dispense. 

Reddish-brown hexagonal crystal the pentadecahydrate is a dark green amorphous substance while the octadecahydrate is a violet cubic crystal the densities are 3.10 g/cm (the anhydrous salt), 1.87 g/cm (pentadecahydrate), 1.709/cm (octadecahydrate) the anhydrous sulfate is insoluble in water and acids the hydrate salts are soluble in water the pentadecahydrate is insoluble in alcohol, but the octadecahydrate dissolves in alcohol. 

Red-to-violet monoclinic crystals (anhydrous acetate is hght pink in color) density 1.705 g/cm becomes anhydrous when heated at 140°C soluble in water, alcohols and acids. 

The oxalate, [Cr(NH3)4H20.Cl]C204, separates in violet-red crystals on the addition of potassium oxalate to a solution of the chloride. It is sparingly soluble in water, and the solution gives a precipitate of calcium oxalate with calcium chloride. A freshly prepared solution of the salt in nitric acid gives no precipitate with silver nitrate. The chlorine atom in the chloro-aquo-salts is within the complex, and hence silver chloride is not at first precipitated by silver nitrate on boiling with nitric acid and silver nitrate, however, chlorine is precipitated as silver chloride. 

It separates in small violet rhombic crystals which resemble chloro-pentammino-cobaltic chloride in appearance. It is soluble in cold water to a certain extent, and only two-thirds of the chlorine is precipitated from solution by silver nitrate at ordinary temperature. In aqueous solution the salt is gradually transformed into the diaquo-salt, [Co(NH3)4(HaO)2]Cl3 dilute nitric acid, if rubbed with the substance, gives reddish-violet crystals of the nitrate, [Co(XH3)4(HaO)Cl](NOs)2 and a cold concentrated solution of ammonium sulphate yields the sulphate, [Co(NH3)4(H20)C1]S04. The corresponding bromide, [Co(NH3)4(H2Q)Cl]Br2, is obtained by filtering a cold saturated solution of the chloride into concentrated hydrobromie acid at 0° C. The precipitate formed is washed with hydrobromie acid and then with alcohol. The bromide is almost insoluble in hydrobromie acid, but more easily soluble in water than the chloride.2... 

Free nitrosylsulphuric acid actually occurs in the lead chambers only under abnormal conditions of working its separation as chamber crystals is most undesirable from the manufacturer s point of view, as not only does it indicate improper regulation of the process, but it also causes the lead walls of the chambers to be attacked unduly. A solution of violet acid is sometimes obtained at the bottom of the Gay-Lussac tower. 

W. Hittorf prepared metallic or violet phosphorus by heating phosphorus in contact with lead for 10 hrs. at a temp, near 500°. The phosphorus dissolves in the lead at the high temp., and on cooling separates from the lead in the form of small, dark, reddish-violet, rhombohedral crystals. The crystals can be separated from the lead by treatment with dil. nitric acid, which dissolves only the lead. The crystals are further purified by boiling them with hydrochloric acid. A. Stock and F. Gomolka recommended the following procedure ... 

Color formers are very sensitive to the addition of acids and solvents. In acid, crystal violet lactone (6) is only partially converted to the colored carboxylic acid (7) with opening of the lactone ring nax (log e) = 603 nm (4.41) in methanol / acetic acid (1/1)]. 

In glacial acetic acid with perchloric acid Crystal Violet [548-62-9] violet-blue-green-green-yellow... 

Pentazocine can be determined by a titri-metric procedure in which the compound is dissolved in glacial acetic acid. Crystal violet is used as indicator and the solution is titrated to a green end-point with 0.1 N perchloric acid. Each mL of 0.1 N perchloric acid at this point is equivalent to 28.54- mg of pentazocine base (3)-... 

Cesium titanium alum forms violet octahedral crystals which are sparingly soluble in cold water, more soluble in hot. These crystals belong to the /3-type alum crystal structure, or those alums that contain a large unipositive ion. The compound is oxidized rapidly in air, and water solutions become turbid on exposure to air, precipitating titanic acid. 

Carminic acid crystallizes from water as bright red crystals that darken at 130° and decompose at 250° it is freely soluble in water, in alcohol, in ether, in concentrated sulfuric acid, and in solutions of alkali hydroxides it is insoluble in petroleum ether and in chloroform its aqueous solutions at pH 4.8 are red-orange to yellow, and at 6.2 are dark red to violet. 

PROP Brown-black powder or dark violet blue crystals. Insol in H2O, acids, and alkalies. IDLH 1000 mg/m (as Mo). 

Properties Reddish-violet, deliquescent crystals. D 1.7043, mp loses H20 at 140C. Soluble in water, acids, and alcohol. 

Production of N,N-dimethylaniline in Western Europe in 1985 was around 9,0001. Among the most important compounds based on N,N-dimethylaniline is Michler s ketone, which is used to manufacture triphenylmethane dyes such as Basic Violet 3 (Crystal Violet) or Basic Green 4 (Malachite Green), which is obtainable by reaction with benzaldehyde in a sulfuric acid medium, followed by oxidation. 

The staining pink, red-violet and yellow red or blue in acid aqueous solutions indicate uric acid crystals specifically and has, therefore, diagnostic value. 

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. 

Acetone-Alkali coloration. Dissob-e a few crystals in i-2 ml. of acetone and add a few drops of aqueous XaOlI solution. A deep violet coloration is produced, and is turned red by acetrc acid but destroyed by mineral acids (see Test 4(6) for Ketones, p. 346, and also Test 2(0) p. 274). 

A. Carry out the following preliminary test. Dissolve a drop or a few small crystals of the compound in 1 ml. of rectified spirit (95 per cent, ethanol) and add 1 ml. of iV hydrochloric acid. Note the colour produced when 1 drop of 5 per cent, ferric chloride solution is added to the solution. If a pronounced violet, blue, red or orange colour is produced, the hydrox amic acid test described below is not applicable and should not be used. 

The preparation of an ion-selective electrode for salicylate is described. The electrode incorporates an ion-pair of crystal violet and salicylate in a PVC matrix as the ion-selective membrane. Its use for the determination of acetylsalicylic acid in aspirin tablets is described. A similar experiment is described by Creager, S. E. Lawrence, K. D. Tibbets, C. R. in An Easily Constructed Salicylate-Ion-Selective Electrode for Use in the Instructional Laboratory, /. Chem. Educ. 1995, 72, 274-276. 

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). 

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