Hexanitrohexaazaisowurtzitane (CL-20)

There are numerous patents on its synth.....you will need a lot of expensive equipment and forbidden precursors

I think it is so expensive (P2O5, palladium on charcoal-catalyst, very specific glass-equipment,acetonitrile solvent, and and and.....)and time-consuming it would most likely be a very frustating project.......

[Edited on 18-2-2005 by BASF]

The method on roguesci if it works will be nearly OTC . Glyoxal can be made like formaldehyde or acetaldehyde by passing ethylene glycol over a hot copper wire, and NBK has seen sulphamic acid at home depot, as has a friend of mine. Only reagent not OTC is the concentrated fuming nitric acid that is needed

[Edited on 18-2-2005 by rogue chemist]

From Ullmann(version on FTP)
__________________________________
Among the numerous processes for producing glyoxal, only those using acetaldehyde [75-07-0] and ethylene glycol [107-21-1] as starting materials have been developed commercially.
From Acetaldehyde. Oxidation with nitric acid was examined by LJUBOWIN as early as 1875 and patented in 1942 [19]. Reaction takes place at ca. 40 °C and is carried out industrially as a continuous process. Maximum yield is ca. 70 %; selectivity is a function of the relative concentrations of reagents. After the removal of excess acetaldehyde, the glyoxal formed, which is contaminated with acetic, formic, and glyoxylic acids, is purified by passage of the aqueous solution through an ion-exchange resin. The solution is then concentrated to a glyoxal content of about 40 %.
Selenium oxide [7446-08-4] is more selective than nitric acid, and the yield is ca. 84 %; the selenium can be recycled by oxidation with hydrogen peroxide [20]. This process has not been carried out on an industrial scale.
From Ethylene Glycol. The gas-phase oxidation of ethylene glycol by atmospheric oxygen in the presence of dehydrogenation catalysts (metallic copper or silver) represents the basis of the Laporte process [21] and has been used in several industrial production processes. Reaction occurs between 400 and 600 °C; the yield is 70 – 80 %. The main impurity is formaldehyde [50-00-0] , whose subsequent separation is difficult. This reaction has also been carried out in the liquid phase and under irradiation.
Other Processes . Ethylene can be oxidized by aqueous nitric acid in the presence of palladium [22] , by atmospheric oxygen, or by selenium oxide deposited on silica [23]. Glyoxal may also be formed by oxidation of acetylene [24] or benzene [25] with ozone. Ethylene oxide has been proposed as a substrate for oxidation. Although oxalic acid and its derivatives can be reduced to glyoxal, these processes have not been developed further.


[19] I. G. Farbenindustrie AG, BF 885 931 (1942).
[20] Air Liquide, FR 2 038 575, 1969 (J. P. Zumbrunn).
[21] Laporte Chemicals, GB 1 272 592, 1963 (B. K. Howe, F. R. Hary, D. A. Clarke).
[22] BASF, DE 1 166 173, 1962 (R. Platz, W. Fuchs); DE 1 231 230, 1964 (R. Platz, H. Nohe).
[23] E. Costa Novella, Ann. Quim. 68 (1972) no. 3, 325 – 332;Chem. Abstr., 77, 113 760 f.
[24] Imperial Chemical Industries, GB 1 071 902, 1965 (R. A. Rennie).
[25] Inmont Corp., US 3 637 860, 1968 (W. P. Keaveney, J. J. Pappas).
-------------------------------------------

I have no idea how easily this work, ideally it would be as easy as formaldehyde for methanol but now you bring up the issue of over oxidaton, which I was unaware of. When I posted that I had not done any indepth research, just what I found in Ullmann's. Well this weekend I will be doing some looking into of the references cited. Hopefully there is something feasible. Are the references above any of the same ones you have loked into? Oxidation of acetylene with ozone seems...well...interesting

[Edited on 18-2-2005 by rogue chemist]

Does anyone know if the Ebele process with glyoxal instead of paraformaldehyde ( ammonium nitrate + glyoxal + Ac2O ) and some pressure has been discussed or attempted ? If it doesn't yield HNIW, maybe it could form another interesting structure or ... nothing

Here is a ChemDraw outline of the SNPE reaction sequence. They use a variety of different amines but the nitration examples are both based on the allylamine condensation product with 40% aqeous glyoxal followed by conventional mixed acid nitration. They state a 40% yield for the N-allyl intermediate but I could not find anything on the yield in the nitration step.

[Edited on 23-7-2008 by Ritter]

Here's a ChemDraw summary of the process worked out by Thiokol & later Cordant. See the following US patents:

5723604
5739325
6147209
7129348

Here is a variation of the CL-20/HNIW process disclosed in US6391130 (see http://www.pat2pdf.org/patents/pat6391130.pdf). In this vasriation HBIW is converted to TADB which is then converted to TADH which is then nitrated with mixed acids to give the explosive.

Actually there are quite a few threads on this substance around.

Some even show what it really looks like structurally.

The drawings above are correct but manage to be correct in a way that conveys little information. The molecule is not flat. The C-C cond between the two 5-membered rings is not ridiculously long.

As you can see from the sketch attached, the piperazine ring is in an inverted boat conformation and the two 5-membered rings parallel each other.

Sometimes the patent drawings are inferior. There is no need to be slavishly devoted to them when more intelligent and informative representations are available.

[Edited on 27-7-2008 by Sauron]

The (perceived) aesthetic differences between 2 different extended structural representations of the same fused ring system misses the point of my posts. I was intending to convey the materials flow & reaction chemistry with a number of variations between patents.

As a further indication of the difficulty involved in this synthesis, attached is the lab-scale setup for this synthesis.

I've tried to condense potassium sulfamate with glyoxal, in many different conditions, no hexasulfamatoisowurzitane was formed or the yield is neglible, instead tetrahydroxodisulfamatopyperazine is obtained in almost quantative yeild.

I got new idea about how CL-20 can be made. Book "Organic Chemistry of Explosives" at page 278 mentiones that TNGU is easily hydrolised to tetranitraminoethane. That can be good precursor to HNIW, idea is to condense tetrahydroxodisulfamatopyperazine with tetranitraminoethane, this should result in formation of isowurzitane cage with 4 nitrogroups already placed, with 2 sulfamate reminants witch can be easily nitrated to HNIW.

Scheme of reactions, i propose is shown below:


[Edited on 22-8-2008 by Engager]

Quote: Originally posted by Engager

I've tried to condense potassium sulfamate with glyoxal, in many different conditions, no hexasulfamatoisowurzitane was formed or the yield is neglible, instead tetrahydroxodisulfamatopyperazine is obtained in almost quantative yeild.

I found some info about condensation of potassium sulfamate with glyoxal. One russian book, here is the reaction's scheme:

There are three sorts of explosives, which can be obtained in that way. Bad news is that the most interesting compound (92) has very small yield. (90) is the well-known TEX, (91) is the powerful explosive (not as powerful, as CL-20), but interesting too.

I think that TNGU is very very powerful itself

Here is some information about Hexanitrohexaazaisowurtzitane, which is sometimes referred to using the acronym HNIW, or by the code-name Cl-20:

Heat of formation (observed): +228 cal/g
Detonation Velocity: 9.38 km/sec
Density: 1.98 g/cm3
Calculated detonation pressure: 428 kbar

The alpha crystal structure consists of rhombic prisms, while the beta consists of either colorless needles or chunky prisms.

Impact sensitivity: using 2.5 kg "hammer" to measure the drop height required to produce a 50% probability of detonation, the alpha form gave an average value of 17cm, while the beta form gave a value of 21cm. Compare this with a value between 23 and 25 cm for HMX.

A plasticized composition of 90% HNIW and a 10% mix of HTPB (used as solid rocket binder) and PL1 (plasticizer which is a 1:1 ratio copolymer of poly(3-butyl-co-3,4-dibutylthiophene and 3-butyl and 3,4-dibutyl thiophene) is recommended since Cl-20 is somewhat more sensitive than HMX. This composition has measured VOD of 7.83 km/s, with calculated pressure of 330 kbar. So while HNIW seems to be powerful in its pure form, this pure compound is not very practical. The safer and easier to handle plasticized/castable composition of HNIW does not have extremely impressive performance. There are several other highly energetic and more insensitive compounds that require less plasticizer and binder to be both tolerably resistant to impact and have desirable moldable/castable properties. Another thing to consider is that HNIW in compositions is significantly less dense (1.82 g/cm3) than the pure compound, whereas the other nitramines do not lose as much density when formed into compositions.


Synthesis of the Precursor:

HBIW is one of the precursors to HNIW, and basically has the same molecular shape and structure of HNIW except that the 6 nitro groups are all replaced by benzyl groups (basically just toluene molecules connected on their methyl groups).

The procedure for making HBIW (2,4,6,8,10,12-Hexabenzyl-2 ,4,6,8,10,12-hexaaza-tetracyklo [5.5.0.0.0] dodecane) stems from J. Org.Chem. (1990), 55, 1459. (1990), 55, 1459th.
To verify only a slight adjustment of preparation was made.

O=CH-CH=O ...... formic acid, CH3CN
........................... ---------------------------> HBIW
C6H5-CH2-NH2


A. From left to right in the picture: formic acid of 80-90% concentration, acetonitrile as solvent, 40% aqueous solution of glyoxal, and bezylamine:



B. The two-liter Erlenmeyer flask will present one liter of acetonitrile, 100 ml, 120 ml of benzylamine (117.9 g, 1.1 mol) and 4.8 ml 80-90% formic acid (5.76 g, 0.11 mol). Flask placed in a bath of ice and water and stir (preferably with a magnetic stirrer). Wait until the temperature drops below 15 ° C.
(picture on the right below)

C. To the solution slowly, stirring constantly, add Glyoxal 40% (72.5 g, 57 ml, 0.5 mol). The whole procedure should take about an hour. Adding either through a dropping funnel or better using a peristaltic pump. The temperature should not exceed 20°C. Shortly after beginning the addition of glyoxal in a solution of the product begins to appear as a white crystalline cavities, (as shown in the picture on the left). When introduced into all the glyoxal reaction, remove the cooling bath and the solution for about 30 minutes stir.



D, then remove the stirrer, cover the top of the flask with aluminum foil, and place it in a dark place. Leave it at room temperature for 24 hours. During this time, will slowly change color from white to a mixture of yellow and orange:


E. Finally, crystals of the product are filtered and twice rinsed with acetonitrile. The filtrate can strip aqueous acetonitrile and use it for the next reaction. In this case, has distilled all the liquid, but only 80-90% of the volume.
The solvent thus obtained can be used for further condensation, it only add acetonitrile to volume of 1100 ml. Do not add water.


F. The product can be obtained by being recrystallized in acetonitrile, and can then be used without any purification for the next reaction. The product from this procedure should be around 90 g (0.12 mol, 76%) of HBIW, you can see the final picture below. HBIW is a slightly yellowish white solid with a melting point of 155-157 °C.


[Edited on 1-11-2012 by AndersHoveland]

Recrystalization of CL-20

Quote: Originally posted by SyphonNexus

Isn't the power of an energetic material the square of its VoD? If so isn't 100 m/s a nice improvement?

attached is information comparing sensitivity of pure Cl-20 to its lower sensitivity co-crystal with HMX.