United States Patent (19) 11 Patent Number: 5,739,325 Wardle Et Al

US005739325A United States Patent (19) 11 Patent Number: 5,739,325 Wardle et al. 45 Date of Patent: Apr. 14, 1998

54 HYDROGENOLYSIS OF 24,68,10,12 Chemical Abstracts, 120: 248721w, Propellants and Explo HEXABENZYL-2,4,6,8,10,12 HEXAAZATETRACYCLO5.5.0.0.0) sives, "The thermal stability of the polymorphs of hexani DODECANE trohexaazaisowurtzitane. Part I”, vol. 120, (1994). Chemical Abstracts, 120: 221778h, Propellants and Explo 75) Inventors: Robert B. Wardle, Logan; W. Wayne sives, "Diagnostic scheme for polynitrocage compounds', Edwards, Tremonton, both of Utah vol. 120 (1994). 73) Assignee: Thiokol Corporation, Ogden, Utah Arnold T. Nielsen et al., Polyazapolycyclics by Condensa tion of Aldehydes with Amines. 2. Formation of 2,4,6,8.10, 12-Hexabenzyl-24.8.10, 12-hexaazatetracyclo (21) Appl. No.: 568,451 (5.5.0.0.0') dodecanes from Glyoxal and 22 Filed: Dec. 7, 1995 Benzylamines', Journal of Organic Chemistry, vol. 55, pp. (51 Int. Cl. ... CO7D 255/04 1459-1466(1990). 52 U.S.C...... 540/554; 149/92 58 Field of Search ...... 149/92; 540/554, Primary Examiner-Richard D. Lovering 540/556; 54.6/1; 564/107, 141, 144 Attorney, Agent, or Firm-Cushman Darby & Cushman IP Group of Pillsbury Madison & Sutro, LLP; Ronald L. (56) References Cited Lyons, Esq. U.S. PATENT DOCUMENTS 57 ABSTRACT 2,459,002 1/1949 Parker et al...... 56.4/144 X 2,485.855 10/1949 Blomquist et al. ... 149/92 X A process for the hydrogenolysis of 2.4.6.8, 10.12 3.228,929 1/1966 Frankel ...... 540/554 hexabenzyl-2,4,6,8.10.12-hexaazatetracyclo[5.5.0.0. 3,535,390 10/1970 Driscoll ...... 149/88 X O'") dodecane ("HBIW") is disclosed. In the process, a 4,432,902 2/1984 McGuire et al ... 149/92 X quantity of HBIW, a cosolvent, and a bromine source are 4,485,237 11/1984 Willer ...... 149/92 X placed into a reaction vessel, Acetic anhydride and a palla 4,487,938 12/1984 Boileau et al...... 548/304 dium hydrogenolysis catalyst are rapidly added to the reac 5,124,493 6/1992 Lukasavage et al...... 149/92 X tion vessel. The hydrogenolysis catalyst should be substan 5,409,617 4/1995 Ross et al...... 210,762 tially free of water. The reaction vessel is purged of an atmosphere capable of reacting with hydrogen, and hydro OTHER PUBLICATIONS gen is quickly introduced into the reaction vessel to convert Anthony J. Bellamy, "Reductive Debenzylation of Hexa the HBIW to tetraacetyldibenzylhexaazaisowurtzitane benzyl-hexaazaisowurtizitane.” Tetrahedron, vol. 51, No. ("TADB"). The acetic anhydride is added immediately prior 16, pp. 4711-4722 (1995). to hydrogen introduction so that the acetic anhydride does Chemical Abstracts, 120: 221757a, Propellants and Explo not have time to react with the HBIW to form an acetylated sives, "Synthesis and explosive performance characteristics derivative prior to commencement of the desired hydroge of polynitro polycyclic cage explosives", vol. 120, p. 232 nation reaction. The process requires very little palladium (1994). catalyst, preferably less than 10% wit/wt based on the HBIW Chemical Abstracts, 121: 38726w, Propellants and Explo substrate. The TADB, precipitated on the palladium hydro sives, "The thermal stability of the polymorphs of hexani genolysis catalyst, is subjected to a second hydrogenation trohexaazaisowurtzitane'', vol. 121, p. 186 (1994). step using a formic acid solvent in the presence of hydrogen Chemical Abstracts, 120: 32623e, Propellants and Explo to form tetraacetyldiformylhexaazaisowurtzitane ("TADF"). sives, "Thermal stability of hexanitrohexaazaisowurtzitane in an Estane formulation”, vol. 120, (1994). 27 Claims, No Drawings 5,739,325 1. 2 HYDROGENOLYSIS OF 2,468,10,12 find conditions which would effect partial or complete HEXABENZYL-2,4,6,8,10,12 debenzylation of HBI.W. The yield of toluene was used as an HEXAAZATETRACYCLO15.5.0.0.0. indicator of the extent of reductive debenzylation. When the DODECANE toluene yield was low, the recovery of starting material was usually high, whereas in those experiments where reason GOVERNMENT RIGHTS able yields of the tetrabenzylated product were obtained, the The U.S. Government has a certain rights in this invention toluene yield was at or slightly below 4 mmol per mmol of as provided for by the terms of contract No. N00014-91-C- starting material. 0254 awarded by the Office of Naval Research. Bellamy's experiments used 1 mmol HBIW (708 mg) in 1O combination with various solvents, acetylating agents, and FIELD OF THE INVENTION hydrogenation catalysts. The following different hydroge nation catalysts were tested by Bellamy: dried Degussa type The present invention relates to the hydrogenolysis of E101 NE/W 10% Pd on activated carbon, dried Pearlman's 2.4.6.8,10,12-hexabenzyl-2,4,6,8,10.12-hexaazatetracyclo catalyst (palladium hydroxide on carbon, 20% Pd), and (5.5.0.0.0'ldodecane, sometimes referred to as "hexa 15 moist Pearlman's catalyst. The catalysts were used at quan benzylhexaazaisowurtzitane” and hereinafter referred to as tities from 70 mg to 710 mg (10% wt?wt to 100% wit/wt “HBIW. based on HBIW substrate). According to Bellamy, at least 50% wit/wt and preferably 100% wt?wt catalyst, based on BACKGROUND OF INVENTION HBIW substrate, was necessary to achieve acceptable An important step in the synthesis of 2.4.6.8,10,12 debenzylation of the HBI.W. hexanitro-2,4,6,8,10,12-hexaazatetracyclo[5.5.0.0.0." The palladium-based catalyst used in the hydrogenolysis dodecane, sometimes referred to as "HINTW" or "CL-20," is step represent a major expense in the overall cost to syn the hydrogenolysis of the chemical intermediate HBIW. thesize CL-20. Arnold T. Nielsen has reported that the HBIW can be synthesized according to the procedure catalyst cost is over $200 per pound of CL-20 ultimately described by Nielsen et al., “Polyazapolycyclics by Con 25 produced. See, copending application Ser. No. 07/292,028, densation of Aldehydes with Amines. 2. Formation of 24, filed Dec. 21, 1988 and Ser. No. 07/989,369, filed Dec. 8, 6,8.10.12-Hexabenzyl-2.4.6.8,10,12-hexaazatetracyclo 1992, and the references cited therein, which applications (5.5.0.0.0') dodecanes from Glyoxal and and references are incorporated herein by reference. Benzylamines,” Journal of Organic Chemistry, Vol. 55, pp. In the original synthesis of CL-20 reported by Arnold T. 1459-66, (1990). An improvement to the hydrogenolysis of 30 Nielsen, "Synthesis of Polynitropolyaza Caged Nitramines.” HBIW would represent an improvement in the overall Chemical Propulsion Information Agency (CPIA), publica synthesis of CL-20. tion number 473, December 1987, the TADB is converted to CL-20 is a polycyclic caged nitramine oxidizer. For most CL-20 via a dinitro so intermediate, existing weapons systems, the most critical ingredient in teraacetylidinitrosohexaazaisowurtzitane, as shown below: both propellant and explosive applications is the oxidizer. 35 CL-20, with its substantial increase in performance output, Ac Ac represents a major breakthrough in energy capabilities for AN 1 N1A. future propellant and explosive systems. It may be possible N N1 to replace existing weapons system energetic fills with CL-20 to increase shaped charge anti-armor penetration, increase missile payload velocity and standoff, increase underwater torpedo effectiveness and lethality, and improve gun propellant impetus. The current open literature techniques of HBIW hydro genolysis are reported by Anthony J. Bellamy, "Reductive 45 Debenzylation of Hexabenzylhexaazaisowurtzitane." Tetrahedron, Vol. 51, No. 16, pp. 4711-22 (1995). A repre sentation of the current hydrogenolysis step is set forth below: 50

Although effective, this route uses large amounts of Pd(OH) ?carbon and the expensive BF-based nitrating agents. 55 / N An improvement to the Nielsen route for the cleavage of Bn NB the final benzyl groups is depicted below: ANAc 1 N1A.Ac ANAc 1 N1A.Ac N3–8 N1 Nos N N1 N N Bn1 YBn ON1 NNo

The product is tetraacetyldibenzylhexaazaisowurtzitane 65 (“TADB"). Bellamy reports the catalytic hydrogenation of HBIW under a variety of conditions with the objective to 5,739,325 3 -continued ON NO2 Bn. Bn ONN N1,No. SNN 1) N35N1 H2, Ac2O N, 1NN2 Pd) Cosolvent 3-k N N Bromine N oN1 YNO, Bn1 NBn Ac Ac As explained in greater detail in copending application ANN 1 N1A.N1 Ser. Nos. 07/292,028 and 07/989,369, it would be an 10 advancement in the art to avoid the formation of the dini x & troso intermediate and the need for expensive BF-based 1. N N NB reagents and to provide a simpler route for the formation of Bll CL-20. It would be a further significant advancement in the art to 15 According to the process, a quantity of HBTW and a provide a process for the hydrogenolysis of 2,4,6,8,10,12 cosolvent are introduced into a reaction vessel. Currently hexabenzyl-2,4,6,8.10.12-hexaazatetracyclo[5.5.0.0.0. preferred cosolvents which have been shown to provide 11ldodecane which requires less catalyst than currently significant improvement are N,N-dimethylformamide known processes, thereby reducing the overall manufactur (“DMF"), N-methylpyrollidone ("NMP"), and 1,2- ing cost of CL-20. It would also be an advancement in the dimethoxyethane. Of course, other known and novel cosol art to provide a process for the hydrogenolysis of 2.4.6.8, vents can be used, but they may not provide the same 10, 12-hexabenzyl-2.4.6.8.10.12-hexaazatetracyclo[5.5.0.0. improvement in reproducibility and in reducing the catalyst 9.0"dodecane which produces high yields of the desired loading as with the cosolvents mentioned above. end product. A bromine source is also added to the reaction vessel. 25 Suitable bromine sources include molecules having active SUMMARY OF THE INVENTION bromine, such as benzyl bromide, acetyl bromide, and bromine gas (Br). The order of bromine source addition is The present invention is directed to a process for the not critical to the present invention. The HBIW, cosolvent, hydrogenolysis of 2.4.6.8,10,12-hexabenzyl-2,4,6,8,10,12 and bromine source are preferably mixed in an atmosphere hexaazatetracyclo[5.5.0.0.0'ldodecane (“HBTW). In 30 the process, a quantity of HBIW, a cosolvent, and-abromine which is substantially non-reactive with hydrogen. For source are placed into a reaction vessel. Acetic anhydride instance, the reaction vessel can be purged with an inert and a palladium hydrogenolysis catalyst are added to the atmosphere, such as a nitrogen. Alternatively, the reaction reaction vessel, followed immediately by introduction of vessel atmosphere can be removed by vacuum. hydrogen into the reaction vessel. Once hydrogen is intro 35 Acetic anhydride and a palladium hydrogenolysis catalyst duced into the reaction vessel, the HBW is converted to are rapidly added to the reaction vessel. It is important that tetraacetyldibenzylhexaazaisowurtzitane ("TADB"). The the acetic anhydride and palladium catalyst are added just acetic anhydride is added immediately prior to hydrogen before the reaction begins to inhibit formation of introduction so that the acetic anhydride does not have time N-benzylacetamide which acts as a catalyst poison. to react with the HBIW to form an acetylated derivative N-benzylacetamide is formed by reaction of HBFW and prior to commencement of the desired hydrogenation reac acetic anhydride. tion. The hydrogenolysis catalyst is preferably added to the reaction vessel in an amount less than 10% wt?wt based on The hydrogenolysis catalyst should be substantially free the HBIW substrate. Typical hydrogenolysis catalysts which of water to inhibit unwanted reaction byproducts. This can can be used include Pd(OH), Pd, and mixtures thereof on be accomplished by washing with the cosolvent. The process 45 carbon commonly used as a catalyst support. Several stan requires very little palladium catalyst, preferably less than dard palladium metal and Pearlman's-type catalysts have 10% withwt based on the HBIW substrate, and most prefer both been found to be suitable. Such catalysts are commer ably less than 5% wit/wt based on the HBIW substrate. The cially available. Similarly, catalysts that are provided either palladium hydrogenolysis catalyst preferably includes a water-wet or dry have been useful. The weight percent of carbon substrate wherein the palladium metal content rela 50 active palladium on carbon is preferably less than 10%, tive to the carbon is less than 10% by weight, preferably less more preferably less than 5%, and can be as low as 3%. than 5%, and can even be used at concentrations less than The hydrogenolysis catalyst is preferably substantially 3%, by weight. free of water. This can be accomplished by washing the The TADB product precipitates on the palladium hydro 55 catalyst with the cosolvent prior to introduction into the genolysis catalyst and is easily recovered by filtration. reaction vessel to remove water associated with the catalyst. According to the disclosed process, the TADB is subjected The palladium catalyst is normally shipped water-wet, with to a second hydrogenolysis step using a formic acid solvent approximately 50% of the weight being water. While not in the presence of hydrogen to form tetraacetyldiformyl wishing to be bound by theory, it is presently believed that hexaazaisowurtzitane ("TADF'). acetic acid, formed by reaction of acetic anhydride in the reaction mixture with the water on the catalyst, reduces the DETALED DESCRIPTION OF THE yield and increases the chances of a failed or incomplete INVENTION reaction. Previous efforts at water removal, such as vacuum The present invention is directed to a process for the drying, which was unacceptable due to fire hazard and hydrogenolysis of 2.4.6.8,10,12-hexabenzyl-2,4,6,8,10,12 65 catalyst activity reduction, or washing with acetic anhydride, hexaazatetracyclo[5.5.0.0.0"ldodecane (“HBIW"). The did not fully remove water and left acetic acid present. first step of the hydrogenolysis process is shown as follows: Washing with the polar cosolvent effectively removes water 5,739,325 S and does not introduce deleterious side products or reduce catalyst reactivity. Ac Ac Ac Ac A.NN 1 N1A1. ANN 1) NA.N1 It has been discovered that addition of the reactive acetic anhydride immediately prior to hydrogen introduction 5 improves the reaction yield, rate, and reproducibility. A Bn1 major contributor to incomplete or low yield reactions is the formation of N-benzylacetamide which acts as a catalyst poison. N-benzylacetamide is formed by the acid catalyzed 10 decomposition of HBIW to yield “free” benzyl amine fol lowed by acetylation of the benzyl amine by acetic anhy dride. This reaction occurs slowly once the reaction mixture is together. To minimize this unwanted reaction, the cosol vent and HBIW are preferably placed in the reaction vessel 15 first, followed by the bromine source. The contents are thoroughly mixed and placed under a nitrogen atmosphere. The acetic anhydride and the washed palladium catalyst are then added quickly, followed immediately by hydrogen 20 introduction. Once the acetic anhydride is added to the It has been found that the resident catalyst onto which the HBIW, the hydrogen must be added rapidly to inhibit product from the first hydrogenolysis precipitated was suf unwanted side reactions. ficient for the second hydrogenolysis reaction, even at dramatically reduced catalyst loading for the first hydro Hydrogen introduction into the reaction vessel to begins 25 genolysis reaction. conversion of HBIW to tetraacetyldibenzylhexaazai sowurtzitane ("TADB"). The TADB product is allowed to precipitate onto the catalyst and is not removed from the The second hydrogenolysis is accomplished using formic catalyst. The cosolvent assists in providing complete pre acid as the solvent. While not wishing to be bound by theory, cipitation. After the hydrogenolysis is complete, the product it is presently believed that formic acid plays an important and catalyst are filtered from the liquid phase and washed role in the hydrogenolysis of TADB. It is postulated that the with a solvent, such as denatured ethanol, methanol, or formic acid converts the benzylamine moiety into a benzy isopropanol. The solvent is preferably miscible with the lammonium formate functionality which is then hydrogeno DMF, acetic anhydride, and acetic acid so that these com lyzed more readily, as shown below:

Ac Ac Ac Ac Ac N an N2. AN TN NAc/

Bn1 3-X. NR OHC1 N

HCOOH HCOOH H2) Ac Ac A.NN 1 N1A.N1

NN N HCoo- NR H pounds can be removed from the desired TADF product. The The hypothesis that protonation is the reason for success in solvent is also preferably immiscible with the desired TADF the second hydrogenolysis reaction is supported by the fact product so that the TADF is not dissolved and washed away that the used catalyst from the conversion of HBIW to with the solvent. It is also important that the solvent have no TADB can also carry out the conversion of TADB to TADF effect on the subsequent hydrogenolysis reaction. with no modification of that catalyst or addition of a second The filtered and washed TADB is sufficiently pure for a catalyst. This establishes that the catalyst is not the limiting second hydrogenolysis reaction in which the TADB product reagent in the removal of the final two benzyl groups. and catalyst are reacted with formic acid to form tet Rather, it suggests that a change in the substrate from raacetyldiformylhexaazaisowurtzitane ("TADF"). This containing a benzylamine moiety to a substrate containing a route differs from the known CL-20 synthesis in using a benzylammonium formate moiety causes this change in second hydrogenolysis step, rather than NO, to remove the 65 reactivity. Furthermore, experimental results show that final two benzyl groups. The second hydrogenolysis reaction when a more robust catalyst than 20% Pearlman's catalystis is shown below: used, such as Degussa E101 NE/W, 10% Pd), that catalyst is 5,739,325 7 8 still effective in the first hydrogenolysis even after having purely exemplary and should not be viewed as a limitation been previously employed in both the first and second on any claimed embodiment. hydrogenolysis reactions. This complete recycle was dem EXAMPLE 1. onstrated on a laboratory scale with a single 10% weight to-weight catalyst loading, based on HBIW substrate. Preparation of 4,10-Dibenzyl-2.6.8, 12teracyl-2, The formic acid preferably has a concentration of 88%, 4,68.10.12-hexaazatetracyclo[5.5.0.0.0) which is the water azeotrope, so that recovery of the formic dodecane (“TADB") acid is simplified. In this way, the formic acid can be reused To a mixture of 122 kg of DMF and 70 kg (686 moles) of after a simple distillation. Of course, the concentration of acetic anhydride in a 75 gallon stirred autoclave (steel formic acid can vary. However, if the formic acid concen reactor) were added 43.2 kg (61 moles) of HBIW, 0.781 (7.4 tration is too dilute, the desired diformyl product will not be 10 moles) of bromobenzene, and 4.63 kg of a 55.3% moisture obtained. The products which arise from the second hydro 10% palladium on carbon catalyst (dry weight of catalyst genolysis reaction are dependant on the reaction medium. was 2.07 kg). The vessel was purged four times with These products vary from the bis-free amine to the com hydrogen. During the purges, the temperature of the reactor pletely protected TADF, as shown below: rose from 21.3° C. to 25.2°C. The reaction was then stirred 15 under 50 psi pressure of hydrogen introduced into the AC Ac reaction mixture via a sparge ring. Over the next 30 minutes, AN 1 N1. the reaction temperature rose to 51.4° C. and cold water was then circulated through the jacket of the flask to control the exotherm. Approximately 140 moles of hydrogen (based on N N pressure drop in the hydrogen tank) were consumed during Bn1 NB this period not counting any hydrogen consumed during the Ac Ac purges. Over the next 1.5 hours, another 120 moles of AcN an N1Ac hydrogen were consumed with the reaction temperature then at 43.1° C. (cold water was stopped circulating when the 25 reaction temperature dropped below 35° C.). The reaction N N was allowed to stir an additional 21 hours during which time HN1 YNH another 40 moles of hydrogen were consumed (total of 300 moles versus a theoretical 250 moles for the reaction). The Ac Ac reactor was purged three times with nitrogen then the AN 1 N2Ac 30 reaction mixture was filtered. The solids were washed with HCOEater roughly 130 l of denatured ethanol to afford the desired product along with palladium catalyst slightly moist with N N Bn1 NBn ethanol and trace amounts of DMF as a gray solid which was used directly in the next reaction. In a total of three reactions Ac Ac 35 / ran as described above, a total of 85.7 kg (82-85% yield) of AN TN NAc the product mixture were obtained. X-X EXAMPLE 2 N HN1 NCHO Preparation4.6.8,10,12-hexaazatetracyclo[5.5.0.0.0'l of 4,10-Diformyl-2,6,8,12-tetraacetyl-2, Ac Ac dodecane ("TADF) AcN n N1Ac A stirred solution of 85 kg of the product mixture from Ple Example 1 above (roughly 150 moles of TADB) in 220 kg 45 of formic acid in a 75 gallon stirred autoclave (steel reactor) N N was purged 5 times with hydrogen. Over the next 4 hours, Bn1 NBn approximately 110 moles of hydrogen were consumed and Ac Ac the reaction temperature rose from 16.1° C. to 25.8°C. Over AN 1 N1A. the next 16 hours, a further 220 moles of hydrogen were N N1 consumed with the reaction temperature at 30.4° C. near the X-S 50 end of that period. The reactor was purged three times with N N nitrogen then the catalyst was separated from the soluble OHC1 YoHO product by filtration. The catalyst was washed with 2001 of water then concentrated in a wiped film evaporator operating The catalyst remaining with the TADB from the previous 55 at a pressure below 20 torr with the distillation occurring at reaction is all that is needed for this reaction. Upon addition 50° C. The wiped film evaporator and autoclave were of hydrogen, the reaction proceeds. The second hydro cleaned with 40 1 of water and 20 1 of denatured ethanol genolysis reaction is slower than the first hydrogenolysis, which were added to the product. Remaining volatiles were due to the reduced activity of the last two benzyl groups removed by drying the product in a vacuum oven at 15 torr towards hydrogenolysis. and 50° C. By this method, 57 kg of the desired product The catalyst is removed by filtration, and the product is (86% yield from TADB) were obtained with an average of recovered by evaporation of the volatile solvents. The cata 0.46% water, 1.1% DMF, and 9.82% formic acid. lyst may be recycled and used again in the process or it may be reprocessed by the catalyst manufacturer. The product EXAMPLE 3 thus obtained is of a purity suitable for direct use in the Palladium Catalyst Comparison nitration reaction to produce CL-20. 65 The following examples are offered to further illustrate A large number of catalysts were examined under stan the present invention. These examples are intended to be dard reaction conditions. All reactions were run using 50 g 5,739.325 9 10 of HBTW, 125 ml of DMF, 75 ml of acetic anhydride, and 1 the same scale analyzed for E101 NE/W 10% catalyst, the ml of bromobenzene. All hydrogenations were ran until cost per pound of CL-20 should be under $5 without any hydrogen uptake ceased and for a minimum of 24 hours. multiple use without reprocessing. Slightly lower costs will Typical effective reaction times were 2-4 hours. Effective be achieved at larger scale. This is an enormous improve ness in a recycle was determined by obtaining a similar yield ment over the cost reported by Nielsen at over $200 per in the first recycle, to that obtained in the initial reaction, pound of CL-20. See, copending application Ser. No. Yields with NMP were generally 3–5% higher. Many cata 07/292,028, filed Dec. 21, 1988 and Ser. No. 071989,369, lysts were found to be excellent in the process. Several were filed Dec. 8, 1992, and the references cited therein. This found to be effective in recycle. The results are reproduced result alone shows the dramatic improvements in cost below in Table 1: achieved using a process within the scope of the present invention. TABLE 1. EXAMPLE 4 Catalyst Metal Loading Yield Type (%) (% to HBIW) (%) Recycle Pilot Scale Preparation of 4,10-Dibenzyl-2.6.8,12 15 E101 NEW 10 5 90 yes tetraacetyl-2,4,6,8.10.12-hexaazatetracyclo[5.5.0.0. E101 NEW 5 5 88 na 9.0"dodecane (TADB") E101 NOW 5 5 89 O E101 O/W 5 10 84 O The procedure of Example 1 was scaled up for use in a E101 RD 5 10 91. yes 1500-gallon glass-lined reaction vessel rated for up to 100 E107 NEAW 10 1O 88 C) psi. All reasonable effort was made to run the reaction E107 NE/W 5 10 86 O according to the procedure of Example 1. However, the E1.17 XN/W 10 5 80 yes amount of time required to load all the reagents into the E196R/W 5 5 89 O reactor and purge the reactor with inert gas before safe hydrogen introduction was significantly increased. While The catalysts were obtained from Degussa Corporation, 25 the hydrogen uptake began immediately on introduction and South Plainfield, N.J. The "E" designation represents palla was rapid for several hours, the total amount of hydrogen dium. The "N" and “O'” designations mean the metal was consumed was roughly fifty percent of the amount theoreti predominantly in the oxide form. The "R" designation cally required to convert all HBIW to TADB. Further, the means the metal was predominantly in the metallic form. temperature rise was significantly slower than on the smaller The "IW" designation means the catalyst was supplied 30 scale. Hydrogen uptake slowed to a near stop roughly 18 water-wet, while the "/D” designation means the catalyst hours into the reaction. was Supplied dry, A small aliquot was removed from the reaction mixture, It was generally found that while certain catalysts could the catalyst removed by filtration, and the majority of be used multiple times in the process without reprocessing, volatiles removed under reduced pressure. The "H NMR of the yield tended to drop after first cycle and more so in 35 the glassy material obtained suggested a mixture of three further cycles. Recycling of the palladium catalyst is shown possible isomeric compounds with two acetyl moieties and four benzyl moieties attached to an intact hexaazaisowurtzi

- HCOOHMr S.

OHC1

cle

The total cost of a kilogram of catalyst was determined 50 tane cage skeleton were the major constituents, shown based on actual production runs and all costs associated with below: the use of the catalyst. These results, reported in Table 2. were obtained on the E101 NEW 10% catalyst.

TABLE 2 55 Quan- Pd Catalyst Pd Pod return Catalyst tity cost Production Recovery credit Net Cost (kg) ($) ($) ($) ($) (S) (Skg) 15 4032 350 1100 2100 6182 412 25 6720 2175 1500 2770 7625 305 7O 21475 6525 3000 17000 14000 2OO

These data show that only about $10 per pound of the CL-20 production costs are catalyst related at this level. 65 Using E101 NE/W 5% catalyst results in lower palladium loss and reduced refining and processing costs. Projected to 5,739,325 11 12 -continued 8.7 kg of a 54% moisture 10% palladium on carbon catalyst Ac designation Degussa E101 NE/W (dry weight of catalyst was 4.00 kg) was washed with 201 of DMF to remove water, NAcN and the DMF was discarded. The catalyst was added to the 3 & reactor wet with DMF. To this mixture were added 438 kg N of acetic anhydride. The vessel was purged four times with Bn1 hydrogen alternating with vacuum. During the purges, the temperature of the reactor rose from 22.1° C. to 23.0°C. The This material was stable in the reaction mixture of DMF, reaction mixture was then stirred under 60 psi pressure of acetic anhydride, and acetic acid indefinitely. Later conver 10 hydrogen which was introduced into the reactor via a sparge sion to the desired TADB established that the 4 and 10 valve. Over the next 50 minutes, the reaction temperature benzyl groups were not removed to any degree in this partial rose to 52° C. and cold water was then circulated through the reaction. This was consistent with previous results that the 4 reactor jacket to control the exotherm. The temperature was and 10 benzyl groups were not removed to any degree under held at or below 55° C. for the remainder of the reaction the reaction conditions. 15 period. The reaction mixture was allowed to stir an addi A minor component that remained initially unidentified tional 3.5 hours. The reactor was purged three times with exhibited a characteristic doublet at 64.23 in the "H NMR nitrogen then the reaction mixture was filtered. The solids spectrum (300 MHz). Dilution of the crude glassy material were washed with roughly 2001 of methanol to afford the with toluene and water separated the minor component from desired product along with palladium catalyst slightly moist the major constituents due to higher solubility of this com with ethanol and trace amounts of DMF as a gray solid pound in water. Isolation of this material allowed simple which was used directly in the next reaction. From this identification of the material as N-benzyl acetamide by 'H reaction, approximately 145 kg of the desired product, not NMR. This identification was verified by comparison with including catalyst weight, were obtained. an authentic sample of N-benzyl acetamide. The presence of It will be appreciated that the present invention provides this compound in the reaction mixture suggests that a 25 a method for the hydrogenation of HBIW which avoids the portion of the HBTW starting material was hydrolyzed under formation of the dinitroso intermediate and provides a the reaction conditions to afford free benzyl amine which simpler route for the formation of CL-20. The present was acetylated under the reactions conditions. This material invention-further provides a process for the hydrogenolysis was found to be a potent poison of the hydrogenolysis of HBW which requires less catalyst than currently known reaction. Only 0.17 g of N-benzyl acetamide was required to 30 processes, thereby reducing the overall manufacturing cost completely inhibit a hydrogenolysis reaction run on a scale of CL-20. The present invention also provides a process for of 25 grams of HBIW treated under standard reaction the hydrogenolysis of HBIW which produces high yields of conditions the desired end product. These data suggest a scenario for the failure of this The present invention may be embodied in other specific reaction to proceed to completion. With a longer time 35 forms without departing from its essential characteristics. involved in introducing all reactants and purging the reactor The described embodiments are to be considered in all with inert gas, there was a greater opportunity for the HBIW respects only as illustrative and not restrictive. The scope of to be hydrolyzed by the acidic medium resulting in forma the invention is, therefore, indicated by the appended claims tion of N-benzyl acetamide that then stopped the reaction rather than by the foregoing description. from proceeding further. This effect was verified by execut The claimed invention is: ing a small scale reaction under the time conditions of the 1. A process for the hydrogenolysis of 2,4,6,8.10.12 large reaction and observing the same result. hexabenzyl-2,4,6,8,10,12-hexaazatetracyclo[5.5.0.0.0. Since the toluene and water extraction was found to 11 dodecane ("HBIW") comprising the steps of: largely remove the N-benzyl acetamide from the mixture of (a) introducing a quantity of HBIW and a cosolvent into diacetyl compounds, the unconcentrated bulk reaction mix 45 a reaction vessel; ture was diluted with toluene and washed several times with water. The toluene layer was concentrated in a wiped film (b) adding a bromine source to the reaction vessel; evaporator to a viscous liquid from which a solid slowly (c) adding acetic anhydride and a palladium hydrogenoly crystallized. The solid obtained was essentially free of sis catalyst to the reaction vessel, wherein the hydro N-benzyl acetamide based on "H NMR analysis. This solid 50 genolysis catalyst is substantially free of water; and was resubjected to the original hydrogenolysis conditions (d) quickly introducing hydrogen into the reaction vessel and yielded TADB in excellent yield based on the amount of wherein HBIW is converted to tetraacetyldibenzyl diacetyl compound in the reaction. This product was con hexaazaisowurtzitane (“TADB"). verted to the desired nitratable TADF under conditions of 2. A process for the hydrogenolysis HBIW as defined in 55 claim 1, wherein the cosolvent is selected from the group Example 2. Although the initial hydrogenation reaction consisting of N,N-dimethylformamide ("DMF"), failed to proceed to completion, the overall effect was small N-methylpyrollidone (“NMP”), and 1.2-dimethoxyethane. with respect to yield. The TADF obtained was indistinguish 3. A process for the hydrogenolysis HBIW as defined in able from that made in the standard process. claim 1, wherein the acetic anhydride is added to the EXAMPLE 5 reaction vessel before the palladium hydrogenolysis cata lyst. Preparation of 4.10-Dibenzyl-2.6.8.12-tetraacetyl-2, 4. A process for the hydrogenolysis HBIW as defined in 46.8.10.12-hexaazatetracyclo[5.5.0.0.0'' claim 1, wherein the palladium hydrogenolysis catalyst is dodecane (“TADB") added to the reaction vessel before the acetic anhydride. To a mixture of 765 kg of DMF in a 500 gallon Pfaudler 65 5. A process for the hydrogenolysis HBIW as defined in reactor (glass lined and rated to handle pressurized gases) claim 1, wherein the bromine source is a molecule contain were added 270 kg of HBIW and 7.52 kg of bromobenzene. ing reactive bromine. 5,739,325 13 14 6. A process for the hydrogenolysis HBIW as defined in 20. A process for the hydrogenolysis HBIW as defined in claim 1, wherein the bromine source is at least one selected claim 19, wherein the solvent is selected from the group from the group consisting of benzyl bromide, acetyl consisting of denatured ethanol, methanol, and isopropanol. bromide, and bromine gas (Br). 21. A process for the hydrogenolysis HBIW as defined in 7. A process for the hydrogenolysis HBIW as defined in 5 claim 19, further comprising the step of reacting the TADB claim 1, further comprising the step of purging the reaction product and catalyst, in a formic acid solvent, with hydrogen vessel of an atmosphere capable of reacting with hydrogen to form tetraacetyldiformylhexaazaisowurtzitane ("TADF"). by replacing said reactive atmosphere with an inert atmo sphere. hexabenzyl-2,4,6,8,10,12-hexaazatetracyclo[5.5.0.0.0.22. A process for the hydrogenolysis of 2,4,6,8,10,12 8. A process for the hydrogenolysis HBIW as defined in 10 11) dodecane ("HBIW") comprising the steps of: claim 7, wherein the inert atmosphere is nitrogen. (a) introducing a quantity of HBIW and a cosolvent 9. A process for the hydrogenolysis HBIW as defined in selected from the group consisting of N.N- claim 7, further comprising the step of mixing the HBIW, dimethylformamide ("DMF"), N-methylpyrollidone cosolvent, and bromine source within the reaction vessel ("NMP”), and 1,2-dimethoxyethane into a reaction under a nitrogen atmosphere prior to the addition of the 15 acetic anhydride and the palladium hydrogenolysis catalyst. vessel; 10. A process for the hydrogenolysis HBIW as defined in (b) adding a bromine source selected from the group claim 1, wherein hydrogen is introduced into the reaction consisting of benzyl bromide, acetyl bromide, and vessel by purging the reaction vessel with hydrogen a bromine to the reaction vessel; plurality of cycles, followed by introduction of hydrogen gas 20 (c) adding acetic anhydride and a palladium hydrogenoly under pressure. sis catalyst which is substantially free of water by being 11. A process for the hydrogenolysis HBIW as defined in washed with the cosolvent; and claim 1, wherein the palladium hydrogenolysis catalyst is (d) immediately introducing hydrogen into the reaction made substantially fee of water by washing the catalyst with vessel wherein HBIW is converted to tetraacetyldiben the cosolvent. 25 Zylhexaazaisowurtzitane ("TADB") and is caused to 12. A process for the hydrogenolysis HBIW as defined in precipitate onto the palladium hydrogenolysis catalyst. claim 1, wherein the palladium hydrogenolysis catalyst 23. A process for the hydrogenolysis HBIW as defined in comprises Pd(OH) on carbon. claim 22, wherein hydrogen is introduced into the reaction 13. A process for the hydrogenolysis HBIW as defined in vessel by purging the reaction vessel with hydrogen a claim, wherein the hydrogenolysis catalyst is a mixture of 30 plurality of cycles, followed by introduction of hydrogen gas Pd(OH) and Pd on carbon. under pressure. 14. A process for the hydrogenolysis HBIW as defined in 24. A process for the hydrogenolysis HBIW as defined in claim 1, wherein the hydrogenolysis catalyst added to the claim 22, further comprising the steps of filtering and reaction vessel in an amountless than 10% wtfwt based on washing the TADB product and catalyst with a solvent. the HBW substrate. 35 25. A process for the hydrogenolysis HBIW as defined in 15. A process for the hydrogenolysis HBTW as defined in claim 24, wherein the solvent is selected from the group claim 1, wherein the hydrogenolysis catalyst added to the consisting of denatured ethanol, methanol, and isopropanol. reaction vesselin an amountless than 5% wtwt based on the 26. A process for the hydrogenolysis of tetraacetylidiben HBTW Substrate. zylhexaazaisowurtzitane ("TADB") comprising the steps of: 16. A process for the hydrogenolysis HBIW as defined in (a) introducing a quantity of TADB precipitated on a claim 1, wherein the palladium hydrogenolysis Catalyst palladium hydrogenolysis catalyst and a formic acid includes a carbon substrate and wherein the palladium metal solvent into a reaction vessel; content relative to the carbon is less than 10% by weight. (b) purging the reaction vessel of an atmosphere capable 17. A process for the hydrogenolysis HBTW as defined in of reacting with hydrogen; and claim 1, wherein the palladium hydrogenolysis catalyst 45 (c) introducing hydrogen into the reaction vessel wherein includes a carbon substrate and wherein the palladium metal TADB is converted to tetraacetyldiformylhexaazai content relative to the carbon is less than 5% by weight. sowurtzitane (“TADF"). 18. A process for the hydrogenolysis HBIW as defined in 27. A process for the hydrogenolysis of tetraacetyldiben claim 1, wherein the TADB product precipitates onto the zylhexaazaisowurtzitane (“TADB") as defined in claim 26, catalyst. 50 further comprising the steps offiltering the palladium hydro 19. A process for the hydrogenolysis HBIW as defined in genolysis catalyst and recovering the TADF product. claim 18, further comprising the steps of filtering and washing the TADB product and catalyst with a solvent.