Heteropolyacids: as efficient catalysts for the nitration of 2,4,6,8,10,12-hexaacetyl-2,4,6,8,10,12-hexaazaisowurtzitane

Abstract

12-hexaazaisowurtzitane (HNIW) more commonly called CL-20 is a novel highdensity cyclic nitramine that is synthesized for the use as an energetic component in propellant formulations. It is usually prepared via nitration of precursors in the presence of concentrated nitric and sulphuric acids. Here in this work, for the first time synthesis of CL-20 from nitration of 2, 4, 6, 8, 10, 12-hexaacetyl-2, 4, 6, 8, 10, 12-hexaazaisowurtzitane (HAIW) in the presence of various clean nitrating agents like heteropolyacids has been reported. In the present conditions, the reactions are fairly green, clean and environmentally friendly. Meanwhile, the effects of reaction temperature, time and other factors on the yields were studied. The structure of the synthesized compound was confirmed by using various spectral techniques like IR, 1 H, 13 C, 14 N-NMR and some of its physical properties.

Recent Applications of Heteropolyacids and Related Compounds in Heterocycle Synthesis. Contributions between 2010 and 2020

“…It is prepared via nitration of precursors in the presence of concentrated mineral acids [166]. A. Ramazani et al [167] reported the green synthesis of CL-20 in the presence of clean nitrating agents such as heteropolyacids (Scheme 55). The optimized conditions were: substrate, 1 mmol; 98% of concentrated nitric acid (10 mL) and a Keggin-type heteropolyacids, for example, H 3 PW 12 0 40 , 100 mg, a reaction temperature of 75 • C, in a reaction time of 2 h. In this condition, a practically quantitative yield of CL-20 was obtained.…”