TNAZ

TNAZ (2.19) is also known as 1,3,3-trinitroazetidine (C3H4N406) and was first prepared in 1983 at Fluorochem Inc. It is reported to be more thermally stable than RDX but more reactive than HMX. Pure TNAZ is more shock sensitive than the explosives based on HMX but less sensitive than analogous PETN. It can be used as a castable explosive and as an ingredient in solid rocket and gun propellant. 

Additive Melting point of additivej°C Melting point of eutecticf C TNAZ content in eutectic/mol % 

Additive Melting point of additivefC Melting point of eutecticfC TNAZ content in eutecticjmol% 

CL-20 (2.20) also known as HNIW [2,4,6,8,10,12-hexa-nitro-2,4,6,8,10,12-hexaazaisowurtzitane (C6H6N12O12)] belongs to the family of high energy dense caged nitramines. 

CL-20 was first synthesized by Nielsen in 1991 and is the most energetic and futuristic high explosive. CL-20-based formulations 

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Fig. 2. High energy explosive molecules (a) PYX (b) nitroheterocycles (1) 3,6-dinitro-j -tetra2ine and (2) 2,4,6-trinitro-j -tria2ine (c) ONC (d) TNAZ (e)...

Fur das Trinitroazetidin werden mehrere Syntheserouten beschrieben, z. B. aus Epichlorhydrin und tert. Butylamin zum 1-tert.-Butylazetidin und anschlieliender, stufenweisen Nitrierung zum TNAZ. 

Nitrolysis of a fert-butyl group is also a key step in the synthesis of the high performance explosive known as TNAZ (6). The nitrolysis of the A-fert-butylazetidine (103) has been achieved with acetic anhydride-nitric acid " and acetic anhydride-ammonium nitrate." ... 

Marchand and co-workers reported a synthetic route to TNAZ (18) involving a novel electrophilic addition of NO+ NO2 across the highly strained C(3)-N bond of 3-(bromomethyl)-l-azabicyclo[1.1.0]butane (21), the latter prepared as a nonisolatable intermediate from the reaction of the bromide salt of tris(bromomethyl)methylamine (20) with aqueous sodium hydroxide under reduced pressure. The product of this reaction, A-nitroso-3-bromomethyl-3-nitroazetidine (22), is formed in 10% yield but is also accompanied by A-nitroso-3-bromomethyl-3-hydroxyazetidine as a by-product. Isolation of (22) from this mixture, followed by treatment with a solution of nitric acid in trifluoroacetic anhydride, leads to nitrolysis of the ferf-butyl group and yields (23). Treatment of (23) with sodium bicarbonate and sodium iodide in DMSO leads to hydrolysis of the bromomethyl group and the formation of (24). The synthesis of TNAZ (18) is completed by deformylation of (24), followed by oxidative nitration, both processes achieved in one pot with an alkaline solution of sodium nitrite, potassium ferricyanide and sodium persulfate. This route to TNAZ gives a low overall yield and is not suitable for large scale manufacture. 

The synthesis of TNAZ (18) via the electrophilic addition of NO+NO2 across the C(3)-N bond of l-azabicyclo[1.1.0]butane (26) was found to be very low yielding ( 1 %) and impractical. Nagao and workers reported a similar synthesis of TNAZ via this route but the overall yield was low. 

Axenrod and co-workers reported a synthesis of TNAZ (18) starting from 3-amino-l,2-propanediol (28). Treatment of (28) with two equivalents of p-toluenesulfonyl chloride in the presence of pyridine yields the ditosylate (29), which on further protection as a TBS derivative, followed by treatment with lithium hydride in THF, induces ring closure to the azetidine (31) in excellent yield. Removal of the TBS protecting group from (31) with acetic acid at elevated temperature is followed by oxidation of the alcohol (32) to the ketone (33). Treatment of the ketone (33) with hydroxylamine hydrochloride in aqueous sodium acetate yields the oxime (34). The synthesis of TNAZ (18) is completed on treatment of the oxime (34) with pure nitric acid in methylene chloride, a reaction leading to oxidation-nitration of the oxime group to em-dinitro functionality and nitrolysis of the A-tosyl bond. This synthesis provides TNAZ in yields of 17-21 % over the seven steps. 

Archibald, Coburn, and Hiskey at Los Alamos National Laboratory (LANL) have reported a synthesis of TNAZ (18) that gives an overall yield of 57 % and is suitable for large scale manufacture. Morton Thiokol in the US now manufactures TNAZ on a pilot plant scale via this route. This synthesis starts from readily available formaldehyde and nitromethane, which under base catalysis form tris(hydroxymethyl)nitromethane (35), and without isolation from... 

Figure 6.8 Archibald, Coburn and Hiskey s route to TNAZ ...

A convenient, one-pot, two-step synthesis of l-azabicyclo[1.1.0]butane (5, R = H) from f -chlorosuccinimide is reported and its application to the synthesis of 133-tnnitroazetidine (TNAZ) is discussed <98SC3949>. Another novel and efficient synthesis of 1-aza-bicyclo[1.1.0]butane (5, R = H) and its derivatives is from 23-dibromopropylamine. The bicyclic 5 (R = H) is also useful in the synthesis of the pendant group of a ip-methylcarbapenem antibiotic <99TL3761>. The reaction of 5 (R = Et and Ph) with tosyl chloride and tosyl azide are described <98T15127,99H131>. 

A comparison of their properties with PATO reveals that the thermal stability of these derivatives is not as good as that of the parent compound, that is, PATO. Some experimental and predicted properties of the nitro derivative of PATO-I [Structure (2.25)] reported by the Chinese are density 1.92 gem"3, m.p. ca 103 °C, calc. VOD 8590ms"1 and Pc] 34.5 GPa. This compound has also been synthesized [70] in HEMRL, Pune, India and the properties are similar to those reported by the Chinese investigators. Indian scientists determined its impact sensitivity also which is h50% = 28 cm. Further work is needed to evaluate its suitability for practical applications as this explosive possesses high density, respectable performance (comparable to RDX) and low m.p. and may prove to be a melt-castable explosive similar to TNT and TNAZ. The nitro derivative of PATO-II is shown in Structure (2.26). Similarly, a new explosive called l,3-bis(l,2,4-triazolo-3-amino)-... 

Watt, D.S., and Cliff, M.W. (2000) Evaluation of TNAZ-a high performance melt-castable explosive. Australian Aeronautical and Maritime Research Laboratory (AAMRL) Report No. DSTO-TR-IOOO, July. 

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