megalomania
March 28th, 2002, 02:59 PM
This months issue of the Journal of Propellants, Explosives, and Pyrotechnics has a paper submitted by Phil Eaton, the chemist who first synthesized ONC a year or so ago, about his latest research. He concluded that octanitrocubane is a huge disappointment. The experimentally determined properties of ONC do not match with what theory said it would, specifically its density. This means ONC is not nearly as explosive as they thought it would be. Oh, there may still be some unfound crystalline structure that may have a higher density, but he thinks it will never be quite so cheap to manufacture, nor perform quite so well as the nearest runner up, heptanitrocubane.
Yes, HpNC is the newest top dog on the block. It is considerably easier to synthesize than ONC (it is the starting material for it too), it has a greater density, it is very stable, etc etc. Too bad it is rather difficult to synthesize. I am not saying it is impossible, even for the home chemists at The Forum, but there is a steep materials curve.
The earlier synthetic required you start with tetranitrocubane, TNC, (a powerful explosive in its own right likely to be a close second to HpNC especially in light of this reaction) mixed in THF which is frozen on a glass plate to around 75 °C while frozen N<sub>2</sub>O<sub>2</sub> is sprinkled on top. When the surface of the glass is slowly allowed to warm up a reaction takes place and you get pentanitrocubane. This very same reaction is continued to make hexanitrocubane (starting with the penta), and then heptanitrocubane (from the hexa). I believe N<sub>2</sub>O<sub>4</sub> forms when you cool NO<sub>2</sub> gas to below its boiling point, 21.15 °C and it freezes at 9 °C.
I know that may seem like it is a bit difficult, but you can get a freezing bath this low with dry ice ,CO<sub>2</sub> and acetone (-86 °C). You can sub acetone with either alcohol (-72 °C), chloroform (-77 °C), ether (-100 °C), or by itself (-78.5 °C). The real challenge is getting enough of this stuff to matter at a price that will not break the bank.
A better way to get HpNC in one batch, but still a bit more complex considering the starting materials is to mix TNC with NaN(TMS)<sub>2</sub>. Specificially, you stir in the NaN(TMS)<sub>2</sub> to the TNC in a 1 to 1 mix of THF and a-methyl THF (solvent mix) cooled to 78 °C. This will form a sodium salt (how this is determined I do not know), then the mix is cooled to between 125 °C and 130 °C where a viscous fluid forms. With vigerous stirring, N<sub>2</sub>O<sub>4</sub> in cold isopentane is added to the fluid, after 1 minute the mix is quenched with a mixture of nitric acid in cold ether. Finally the whole damn thing is dumped into water. The less NaN(TMS)<sub>2</sub> you use, the more penta- and hexanitrocubane you will get, HpNC requires at least 4 equivalents the molar mass of TNC (an excess).
The reaction scheme...
<img src="http://www.roguesci.org/hpnc_rxn.jpg" alt="" />
Incidentally, you cannot synthesize octanitrocubane from either above reaction. Now then, wherever shall I get my hands on some NaN(TMS)<sub>2</sub>? Except for the cold temperatures, this entire synthesis is rather simple in that none of the chemicals or equipment is beyond the scope of the amateur chemist. I will try to present some more details in time. Until then, if anybody has any journal references or outright reprints they would like to present on this subject, please do so.
Yes, HpNC is the newest top dog on the block. It is considerably easier to synthesize than ONC (it is the starting material for it too), it has a greater density, it is very stable, etc etc. Too bad it is rather difficult to synthesize. I am not saying it is impossible, even for the home chemists at The Forum, but there is a steep materials curve.
The earlier synthetic required you start with tetranitrocubane, TNC, (a powerful explosive in its own right likely to be a close second to HpNC especially in light of this reaction) mixed in THF which is frozen on a glass plate to around 75 °C while frozen N<sub>2</sub>O<sub>2</sub> is sprinkled on top. When the surface of the glass is slowly allowed to warm up a reaction takes place and you get pentanitrocubane. This very same reaction is continued to make hexanitrocubane (starting with the penta), and then heptanitrocubane (from the hexa). I believe N<sub>2</sub>O<sub>4</sub> forms when you cool NO<sub>2</sub> gas to below its boiling point, 21.15 °C and it freezes at 9 °C.
I know that may seem like it is a bit difficult, but you can get a freezing bath this low with dry ice ,CO<sub>2</sub> and acetone (-86 °C). You can sub acetone with either alcohol (-72 °C), chloroform (-77 °C), ether (-100 °C), or by itself (-78.5 °C). The real challenge is getting enough of this stuff to matter at a price that will not break the bank.
A better way to get HpNC in one batch, but still a bit more complex considering the starting materials is to mix TNC with NaN(TMS)<sub>2</sub>. Specificially, you stir in the NaN(TMS)<sub>2</sub> to the TNC in a 1 to 1 mix of THF and a-methyl THF (solvent mix) cooled to 78 °C. This will form a sodium salt (how this is determined I do not know), then the mix is cooled to between 125 °C and 130 °C where a viscous fluid forms. With vigerous stirring, N<sub>2</sub>O<sub>4</sub> in cold isopentane is added to the fluid, after 1 minute the mix is quenched with a mixture of nitric acid in cold ether. Finally the whole damn thing is dumped into water. The less NaN(TMS)<sub>2</sub> you use, the more penta- and hexanitrocubane you will get, HpNC requires at least 4 equivalents the molar mass of TNC (an excess).
The reaction scheme...
<img src="http://www.roguesci.org/hpnc_rxn.jpg" alt="" />
Incidentally, you cannot synthesize octanitrocubane from either above reaction. Now then, wherever shall I get my hands on some NaN(TMS)<sub>2</sub>? Except for the cold temperatures, this entire synthesis is rather simple in that none of the chemicals or equipment is beyond the scope of the amateur chemist. I will try to present some more details in time. Until then, if anybody has any journal references or outright reprints they would like to present on this subject, please do so.