Toluidine(redirected from Para-tolidine)
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any of three amino derivatives of toluene.
Ortho, meta, and para isomers of toluidines are known (see Table 1). Toluidines are readily soluble in organic solvents but poorly soluble in water; they may be steam-distilled, and they darken (oxidize) upon storage in light in the presence of air.
Toluidines are obtained industrially by the reduction of nitro-toluenes using iron and hydrochloric acid. They are similar to aniline in their chemical properties. They form salts with acids and
|Table 1. Selected properties of toluidines|
|Melting point (°C)||Boiling point (°C)||Density at 20°C (g/cm3)|
|Ortho-toluidine(1,2-). . . . . . . . . .||–24,4 (unstable)||200.3||0.9984|
|Ortho-toluidine (1,6-). . . . . . . . . .||–16.25 (stable)||200.3||0.9984|
|Mete-toluidine(1,3-or 1,5-). . . . . . . . . .||–30.4||203.4||0.9891|
|Para-toluidine (1,4-). . . . . . . . . .||44.5–45,0||200.55||1.046|
undergo diazotization, acylation, halogenation, sulfonation, and alkylation. Toluidines are used in the manufacture of various dyes.
B. L. DIATKIN