Rosaniline production

Rosaniline or magenta was originally obtained by oxidising with arsenic acid a mixture of aniline with 0- and />-toluidine. The product was then lixiviated and treated with common salt, which converted the ai senate into the hydrochloride of rosaniline. Pararosaniline was prepared in a similar way fiom a niixtuie of aniline and /-toluidine. The series... 

The principle of forming the important inner salts of sulfonated triphenylmethane derivatives had thus been discovered. All of the commercially important products within this group are derived from phenylated rosaniline corresponding to the structure 121. 

Volney patented in 1874 an expl intended for use in torpedoes contg Mononitronaphthalene 20.8, K nitrate 68.6 and S 10.6%. Another patent (1897) for cannon smokeless powder described the mixing of 86.00 p of dodecanitro-cellulose with 7.82 p of rosaniline or its homologues and 6.18 p of benzene, all dissolved in acetone. According to Ref 3, the production of Nitro-starch started in the USA in about 1888, under the name Volney s Powder ... 

A rapid test for glycol in motor oil involves testing colorimetrically for the formaldehyde product of the cleavage with p-rosaniline hydrochloride and sulfurous acid. A wine-colored, quinoid-type dye forms. 

Numerous patents followed in England and France, depending on the action of other oxidising agents than stannic chloride. In some of these patents, however, it is not clear whether rosaniline or some other dyestulf such as mauve is really produced. Renard frcres introduced their products, still very impure, under the name fuchsine. ... 

On treating rosaniline with aldehyde and sulphuric acid, a blue dyestuff is formed, which, on treatment with sodium thiosulphate in acid solution, yields aldehyde green. For its preparation, a mixture of rosaniline, aldehyde, and sulphuric acid is heated, till the product produces ablue-violet solution with water. It is then poured into a very dilute solution of sodium thiosulphate. S ulphur and a grey compound separate, while the green remains dissolved. It may be precipitated by addition of zinc chloride or acetate of soda fin one case a zinc double salt, and in the other a free base, is obtained. 

Of course, the products obtained from rosaniline contain one methyl-group more than is expressed in the above formulae its position can only he a matter of speculation. 

When coal is distilled many products are formed. Among these is aniline, one of the greatest dyestuff intermediates. This compound is the basis of many dyes such as aniline black, Rosaniline, and nearly every color of the rainbow. 

A group of other methods for determining bromide is based on the coloured products formed by bromination of various organic compounds by bromine produced in the oxidation of bromide. The reaction with rosaniline gives tetrabromorosaniline [11,12], and fluorescein... 

Hydroxy anthranilic Acid (5-OH-AA). This was synthesized from m-hydroxybenzoic acid by coupling with diazotized rosaniline and subsequent reduction with sodium dithionite. The recrystallized product had a melting point of 242°C. (dec.). 

The rosanilins are powerful triacid bases, are colorless, but combine with acids to form brilliantly colored salts. Fuchsine is industrially obtained from anilin oil, which contains both anilin and toluidin, neither of which in the pure state will produce a red color. The process consists essentially in heating the-oU with a mixture of nitro-benzene, hydrochloric acid and iron filings. The product is a mixture of the chlorids of rosanilin and pararosanilin, is in hard, green crystals, soluble in water and alcohol, to which it communicates a brilliant red color. 

Kolbe and R. Schmitt by heating phenol and oxalic acid with sulphuric acid obtained a red dyestuff which they called rosolic acid. Caro and Wanklyn obtained it by diazotising rosaniline and boiling the product with hydrochloric acid. They, and also Graebe and Caro, gave it an incorrect formula. Schorlemmer and R. S. Dale obtained from it a substance called aurine, which Caro and Graebe synthesised from phenol and dihydroxybenzo-phenone. 

Industrial Products. Fischer s thesis leading to the doctorate at Strasbourg in 1874, was concerned with phthalein dyes, particularly fluorescein and ordn-phthalein. At Munich, Emil and cousin Otto Fischer investijpited rosaniline, the dye prepared by A. von Hofman in 1862 by the oxidation of aniline and toluidine. They converted one... 

Schiff s reagent is an aqueous solution formed by combining p-rosaniline hydrochloride (basic fuchsin), sodium bisulfite, and concentrated hydrochloric acid (Eq. 25.10). The reagent reacts with aldehydes to produce an imine, also called a Schiff base, that is magenta or purple in color (Eq. 25.11). The mechanism for forming the addition product presumably involves nucleophilic attack of sulfur on the aldehydic carbonyl group. 

Bromide ions are oxidized in slightly acidic media with hypochlorite to bromate. The excess of the h)q)ochlorite is taken away by reacting it with sodium formate, and bromide ions are added in excess. The reaction between the bromate and the bromide results in bromine (amplification). The bromine is reacted with the rosaniline reagent (basic fuchsin). The product of this reaction is dissolved in butanol, and the absorbance is measured at 573 mn. 

Product of reaction with p-rosaniline acid bleached dye and FICFIO (spec A =... 

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