Anilinium dyes

The products obtained on oxidation of aminobenzene (aniline) and other ami-noaryl compounds with oxygen and/or peroxide are somewhat dependent on the specific conditions used. For example, freshly distilled aminobenzene (aniline) is colorless, but in the presence of air, it readily darkens and small quantities of crude anilinium dyes result. The same materials, which have been used since the middle of the nineteenth century to color fabric, also result when other oxidizing agents are used, and indeed, the dye industry of that time was built on the oxidation of aniline and related compounds (this chapter). With both air and peroxides, aminobenzene (aniline) has been reported to undergo oxidation to yield, among others, phenylhydroxylamine, nitrosobenzene, p-hydroxynitrosobenzene, benzophenone, and nitrobenzene (Scheme 10.12). 

Aniline, abbreviated NH2, where is CsHs, is an important organic base used in the manufacture of dyes. It has AT], = 4.3 X 10 °. In a certain manufacturing process it is necessary to keep the concentration of < NH3 (aniline s conjngate acid, the anilinium ion) below 1.0 X 10 ° M in a solntion that is 0.10 M in aniline. Find the concentration of NaOH required for this process. 

Aniline, originally derived from coal tar, spawned the synthetic dye industry in the nineteenth century it is stUl used in the manufacture of dyes such as indigo (used in blue jeans), as well as in the manufacture of polyurethane, pharmaceuticals, and other chemicals. Consider the aqueous reaction shown in Table 1.1 between aniline and anilinium ion ... 

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