Uses
4-PHENYLAZO-1-NAPHTHYLAMINE is used as acid-base indicator. pH 4.0 (red) to 5.0 (orange).
Preparation
aniline diazotization, and Naphthalen-1-amine coupling.
Safety Profile
Mutation data reported. When heated to decomposition it emits toxic vapors of NOx.
Purification Methods
Crystallise the dye from cyclohexane or aqueous EtOH. [Brode et al. J Am Chem Soc 74 4641 1952, Beilstein 16 H 361, 16 III 406, 16 IV 546.]
Properties and Applications
brilliant red light yellow to brilliant yellow orange (mineral oil). Red acicular crystal, melting point 123 ℃. Soluble in alcohol and benzene. In concentrated sulfuric acid for magenta; After dilution for red light brown, precipitation, At 2% hot hydrochloric acid solution for magenta solution, there are residues. Dye alcohol solution to join concentrated sodium hydroxide solution for yellow brown. Used for oil, paraffin wax, paint color.
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Standard
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Light Fastness
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Heat-resistant(℃)
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Water
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Sodium Carbonate(5%)
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Hydrochloric acid(5%)
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Melting point
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Stable
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ISO
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Well
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109
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75
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Insoluble
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No change
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Poor
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