Preparation of sym-trinitrobenzene

Direct nitration of m- dinitrobenzene. Hepp [30] who first used this method in 1887, reported that he was able to nitrate only two thirds of the dinitrobenzene used, in spite of using anhydrous nitric acid and fuming sulphuric acid. 

De Bruyn [16] in 1894 could not obtain a yield higher than 50%, by reacting 500 g anhydrous nitric acid and 1000 g of fuming sulphuric acid with 60 g of m- dinitrobenzene, in spite of carrying out the process for 5 days (1 day at 80-100°C and the next 4 days at 110°C). 

Trinitrobenzene has three good qualities as an explosive high stability, great explosive power, and a low sensitiveness to impact and friction. There were good reasons for seeking more economic production methods. These investigations were particularly intensive during World War T. 

Radcliffe and Pollitt [45a] found that on nitrating m- dinitrobenzene with a mixture of anhydrous nitric acid Mid 60% oleum at 110-120°C for 6 i hr, a 71% yield could be obtained, and that by using 20% oleum a 56% yield was obtained. According to Drumond [46], a yield amounting to only 29% theoretically can be obtained as a result of nitration with a mixture of nitric acid and 20% oleum at 130°C for 3 hr. 

The results of Hepp, Lobry de Bruyn and Desvergnes have been confirmed by T. Urbanski and Simon [46a]. 

---

The Griesheim method is generally used for the laboratory preparation of sym-trinitrobenzene. However, it is too expensive to be applied in industry. Trinitrobenzene prepared in this way is much more costly than trinitrotoluene, whereas the gain in explosive power obtained is relatively small. 

The preparation of sym-trinitrobenzene by cyclization of nitromalonic aldehyde (Hill and Torray [55]) ... 

Reactions specific to sym-trinitrobenzene Addition compounds Preparation of sym-trinitrobenzene Direct nitration of m-dinitrobenzene Preparation from a-trinitrotoluenc Preparation from picryl chloride Preparation from benzyl chloride Preparation from m-xylene Other preparatory reactions... 

---