1,3,5-Trinitrobenzene can be prepared by heating _m_-dinitrobenzene
with nitric acid and sulfuric acid to 120'0;[1] by heating
2,4,6-trinitrotoluene with fuming nitric acid in a sealed tube
at 180'0 for three hours;[2] by heating 2,4,6-trinitrobenzoic acid
or its sodium salt with water, alcohol, dilute sodium carbonate
or other suitable solvent.[3]
[1] Ber. 9, 402 (1876); Ann. 215, 344 (1882).
[2] Ber. 16, 1596 (1883).
[3] D. R. P. 77,353; Frdl. 4, 34 (1894).