1,2,4-Trichlorobenzene → 2,4,5-Trichloronitrobenzene

Participants

Reaction Steps

A mixture of 300 ml concentrated H2SO4 (98%) and 150 ml concentrated HNO3 (90%) was prepared in a 2 liter flask equipped with an agitator, thermometer, and dropping funnel. A total of 90.8 gm of 1,2,4-trichlorobenzene (0.5 mol) was added to the acid mixture at 70°-90° C. over a 1 hour period of time. The reaction was maintained at this temperature for 2 to 3 hours or until analysis of the reaction mixture showed the reaction to be complete. Work-up of the product involved addition of 1 liter of cold water to the reaction mass while maintaining a temperature from 55°-65° C. Separation of the organic and aqueous layers gave the desired product, 1,2,4-trichloro-5-nitrobenzene. Crude yield is 95-98% of theory with an isomer purity of 91-95%. Subsequent reactions outlined in Example 1 show this material to be suitable for preparation of TCDD free 2,4,5-TCP and 2,4,5-T.

Provenance & Evidence