Study on Synthesis Technology of 4,6-Dinitro-l,2,3- Trichlorobenzene and Waste Acid Recyling

The nitration of 1,2,3-trichlorobenzene are studied in the binary system of sulfuric acid and nitric acid. The effect of molar ratio of raw materials,reaction temperature and reaction time on the yield are evaluated in the system of nitric acid/sulfuric acid.The optimum process parameters are selected in the system of 98% of sulfuric acid and 65% of nitric acid as follows: n(1,2,3-trichlorobenzene):n(sulfuric acid):n(nitric acid)= 1:11.3:2.3,reaction temperature 65 °C and reaction time 4.5 h.The yield of 4,6-dinitro-1,2,3-trichlorbenzene is 93.95%.The concentration of waste acid can reach to about 95% by extracting and distilling in vacuo. Both the sulphuric acid and residue after recrystallization can be recycled as starting materials in another synthetic reaction of 4,6-dinitro-1,2,3-trichlorbenzene,the product is obtained in yields greater than about 94 mole percent with purity being greater than about 99w%,The structure of target product is characterized by IR,HPLC and Element analysis.