Heteropolyacids (HPAs) as Heterogeneous Catalysts: A Novel Catalytic Method for Synthesis of HNIW (CL-20)

摘要

Hexanitrohexaazaisowurtzitane (HNIW or Cl-20) is a high-energetic material with a cage structure. It is considered as the most powerful explosive. It is usually prepared via nitration of precursors with concentrated nitric and sulfuric acids. We report herein for the first time the use of an efficient catalytic and mild reaction condition for nitration of 2,6,8,12-tetraacetyl-4,10-diformyl-2,4,6,8,10,12-hexaazaisowurtzitane (TADFIW). It has been well documented that heteropolyacids (HPAs) are an efficient and green catalysts. So we use it as nitric acid activator. This strategy gave us a milder condition for nitration reaction. Also we could run reactions in reasonably lower temperature. All these modifications gave us excellent results. By the use of new nitrating agents, the reaction eliminated the use of concentrated sulfuric acid and was environmental friendly. The structure and purity of the compounds were characterized by elemental analysis, HPLC, IR, 1HNMR. Meanwhile, the effects of the reaction temperature, time and other factors on the yield were analyzed.