The Synthesis Of 4,4'-dichloro-2,2',3,3',5,5',6,6'-octanitroazobenzene

Nowdays,the heat-resistant explosive with good heat resistance has been one of the hot topics in the synthesis field.4,4'-dichloro-2,2',3,3',5,5',6,6'-octanitroazobenzene is a very important intermediate of heat-resistant explosive,which has a N=N group and many nitro groups.It has a large conjugated system and its decomposition temperature is 340 ?.4,4'-dichloro-2,2',3,3',5,5',6,6'-octanitroazobenzene has many derivatives,such as BTDAONAB?BTeDAONAB? BNFDAONAB? BAFDAONAB? BNTDAONAB,etc.The decomposition temperature of BTeDAONAB is 550 ?,it is the best heat-resistant explosive reported in the word.The aim of this study is to find the best way of synthesis high yield and high purity 4,4'-dichloro-2,2',3,3',5,5',6,6'-octanitroazobenzene,and lay the foundation for industrial production.Firstly,4-chloro-3,5-dinitrobenzoicacid was prepared by 4-chlorobenzoicacid using fuming sulfuric acid and nitric acid.The product of 4-chloro-3,5-dinitrobenzoicacid was identified by melting point,TLC,IR.The single crystal of 4-chloro-3,5-dinitrobenzoicacid was prepared by solvent evaporation method.Its molecular formula is C7H3ClN2O6 and its molecular weight is 246.56,It belongs to monoclinic system with a=8.9159(2)?,b=8.9247(2)?,c=22.7367(6)?,?=90.758°,V=1809.03(8)?3,Z=8,DC=1.811 g?cm-3.The synthesis of 4-chloro-3,5-dinitrobenzoicacid was optimized by singe factor experiments,such as reaction time,reaction temperature and amount of nitric acid.The results show that the best experimental condition were: reaction time was 4 h,reaction temperature was 95 ?,amount of fuming sulfuric was 20 mL,amount of nitric acid was 18 m L,amount of 4-chlorobenzoicacid was 5 g,and the best production yield was about 87.2%.Secondly,4-chloro-3,5-dinitroaniline was prepared by 4-chloro-3,5-dinitrobenzoicacid using sodium azide.The product of 4-chloro-3,5-dinitroaniline was identified by melting point,TLC,IR.The single crystal of 4-chloro-3,5-dinitroaniline was prepared by solvent evaporation method.Its molecular formula is C6H4ClN3O4 and its molecular weight is 217.57,It belongs to monoclinic system with a=14.1945(7)?,b=8.1107(3)?,c=15.3834(6)?,?=115.472(6)°,V=1598.90(12)?3,Z=8,DC=1.808 g ? cm-3.The synthesis of 4-chloro-3,5-dinitroaniline was optimized by singe factor experiments,such as reaction time,reaction temperature and amount of sodium azide.The results show that the best experimental condition were: reaction time was 4 h,reaction temperature was reflux temperature,amount of fuming sulfuric was 10 m L,amount of sodium azide was 2 g.amount of trichloromethane was 20 mL,amount of 4-chloro-3,5-dinitrobenzoicacid was 5 g,and the best production yield was about 94.3%.Finaly,4,4'-dichloro-2,2',3,3',5,5',6,6'-octanitroazobenzene was prepared by 4-chloro-3,5-dinitroaniline using nitric acid in the presence of concentrated sulfuric acid.The effects of reaction time,reaction temperature,nitrating agent and post-treatment on the yield of crude products were investigated.The results show that the best experimental condition were: reaction time was 6 h,reaction temperature was 80 ?,amount of concentrated sulfuric acid was 125 mL,amount of nitric acid was 7.5 mL,amount of 4-chloro-3,5-dinitroaniline was 5 g,and the best production yield was about 82%.We tried to separate the crude product by column chromatography separation,solvent separation,TLC,and the study showd that the best separation method was TLC.We finally got two products 4,4'-dichloro-2,2',3,3',5,5',6,6'-octanitroazobenzene and 4,4'-dihydroxy-2,2',3,3',5,5',6,6'-octanitroazobenzene which were identified by melting point,TLC and MS-ESI.