Synthesis Of Polynitrostilbenes

3-Amino-2,4,6-trinitrotoluene was efficiently synthesized with 3-methylaniline as starting material, which was obtained through the ethyl chlorocarbonate’s protection of amino group, then nitrated by the nitro-sulfuric acids, followed by hydrolysis under acidic conditions. Also, benzyl groups could be radically brominated and oxidated to gain a series of aromatic benzaldehydes. As precursors,3-amino-2,4,6-trinitrotoluene and 2,4,6-trinitrotoluene were condensed with aromatic aldehydes, respectively, to afford the polynitrostilbenes by Knoevenagel reaction.Mesitylene was brominated using N-bromosuccinimide in the presence of azobisisobutyronitrile to give 1,3,5-tris(bromomethyl)benzene, then nucleophilic attacked by 2-nitro-propane anion to get benzene-1,3,5-tricarbaldehyde. The yield was 50.6% in total. In addition, terephthalaldehyde and isophthalaldehyde were prepared in the same methods, the yields were 54.7% and 54.8% respectively in total.The single crystal of 1,4-bis(3-amino-2,4,6-trinitrophenylethylene)benzene was obtained in the N, N-dimethylformamide. The structure and data of single crystal demonstrated that the C=C conjugated double bonds were trans-configuration. Moreover, the formation of inter-and intra-molecular hydrogen bonds was occurred between hydrogen and oxygen or nitrogen.The thermal stability was studied by detection of the melting points and differential scanning calorimeter. The results revealed that introduction of amino group to the polynitrostilbenes could enhance their thermal stability, and the expansion of π-conjugated system could improve the stability as well. Also, the thermal stability was associated with the operations of molecular symmetry.