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CHAPTER XV

OTHER NITRO DERIVATIVES OF PHENOLS

PICRIC ACID ISOMERS

APART from picric acid, unsymmetrical β− and γ− trinitrophenols are known:

β γ

The β− isomer or 2,4,5-trinitrophenol (m. p. 96°C) may be obtained by nitration

of 3,4-dinitrophenol, the γ− isomer or 2,3,6-trinitrophenol (m. p. 118°C) by nitration

of 2,3-dinitrophenol. Since they are not formed during the nitration of phenol,

they are not present in picric acid and are not of any practical importance.

“ISOPICRIC ACID”

Nietzki and Dietschy [1] found the product they obtained by reacting an alcoholic

solution of KOH with “trinitro-phenylhydroxylamine” (which later was proved

to be trinitroaniline, as Borsche [2] showed in his investigation already mentioned)

was a potassium salt of “isopicric acid” :

(1)

The melting point of the latter is close to that of picric acid (117-118°C) but