DENSITY ESTIMATION FOR NEW SOLID AND LIQUID EXPLOSIVES · PDF filedensity estimation for new...

00 o 17 February 1977

Final Report

May 17, 1976, to February i6, 1977

DENSITY ESTIMATION FOR NEW SOLID AND LIQUID EXPLOSIVES

By: Craig M. Tarver, Clifford L. Coon and John M. Guimont

Prepared for:

NAVAL SURFACE WFAPONS CENTER

White Oak Laboratory

Silver Spring, MD 20910

Attention: Mr. Charles Dickinson

Contract No. N60921-C-0146

SRI Project PYU 5425

;> APR 11 1977 iIt

S I STANFORD RESEARCH INSTITUTEMenlo Park, California 94025 • U.S.A.

ADroved for Public release; distribution unlimited

a STANFOR RtERH NMT13 Mel Pak aioria905 USA

17 Februay--977

Final Report. ,/ -

lay 1-7-,.z-976"*o Febu- 77

DENSITY ESTIMATION FOR NEW SOLID AND LIQUID EXPLOSIVES,

By Craig M./Tarver, Clifford L Coon and& John A Guimont ," jr" /'/ -*+- /

Prepared for:

NAVAL SURFACE WEAPONS CENTER


Silver Spring, AID 20910

Attention: Mr. Charles Dickinson

Contract No. N6421-76-C-146

SRI Project PYU 5425

Approved:

M. E. Hill, Director

Chemistry Laboratory A.IP lO ,. ---

I ileIS ~

P. J. Jorgensen, Executive Director CDC

Phyiscal Sciences Division .......................................-. iV+

\•i :

PREFACE

This report is submitted in partial fulfillment of the contractual

obligation for Contract No. N60921-76-C-0146 entitled, "Density Estimation

for New Solid and Liquid Explosives." The report contains a summary of

work performed during the period May 17, 1976, through January 16, 1977.

The research program was performed by staff of SRI's Physical

Sciences Division under the supervision of M. E. Hill and Donald L. Ross.

Crai- Il. Tarver and Clifford L. Coon were the principal investigators.

Other personnel who participated in tile research include John M. Guimont,

Gerald E. Manser, Robert L. Simon, and D. V. H. Son.

We wish to acknowledge the valuable suggestions and discussions

given to this project by Dr. M. J. Kamlet, Project Monitor, and Dr.

Horst G. Adolph of Naval Surface Weapons Center.

ii

REPORT HIGHLIGHTS

The group additivity approach to estimating density was studied and

shown to be reasonably accurate. The den.i Lies of approximately 180

explosives were estimated. Where direct comparison was possible, 375

of the values were accurate within 1% and 70% were accurate within 2%.

rTcurrently, the synthesis of energetic oxidizers was investigated

iii

SUMMUARY

The group additivity approach was shown to be applicable to density

estimation. The densities of approximately 180 explosives and related

compounds of very diverse compositions were estimated, and almost all the

estimates were quite reasonable. Of the 168 compounds for which direct

comparisons could be made (see Table 6), 36.9% of the estimated densities

were within 2-35, 8.9% were within 3-4%, and 9.0% were more than 4% dif-

ferent from the measured densities. Thus, of the densities estimated in

this study, 82% were within 3% of the measured density. The average

absolute error in density was approximately 0.022 g/cm3 , and the absolute

error in density exceeded 0.04 g/cm3 for only 24 of the 168 compounds

(14.3%). The largest errors occurred for compounds with several bulky,

highly polar groups in close proximity, and for compounds containing

groups whose calculated molar volumes were based on density data for only

two or three compounds. As more density data for a certain group confi-

guration become available, the molar volume can be determined more

accurately, and the overall agreement between measured and estimated

densities of compounds containing that group should improve.

Synthetic work was carried out on a number of newly postulated

explosives or explosives whose syntheses were expected to be difficult.

Progress was made toward the synthesis of 3,6-bis(nitrimino)-3,6-dihydro-

1,3,4,5-tetrazine and 3,5-bis (nitrimino)-hg-2,3,4-triazoline, which conta i

no hydrogen and are highly energetic. Syntheses were developed for the

preparation of the important intermediates hexachloroazobi s formalidi lne

and 3,5-bis(chlorimino)- A-1,2,4-triazoline. In addition, the oxidation

of diaminotetrazine was partially successful in that the partially

oxidized intermediate, 3-amino-6-hydroxylaino-s-tetrazine, was isolated.

iv

CONTENTS

PREFACE ................................. ......................... ii

REPORT IIIGIILIGHTS ................................................ iii

SULM \ARY .......................................................... iv

LIST OF I LLUSTPu\TIONS ............................................ vi

LIST OF TABLES ................................................... vi

I DENSITY ESTIMATION ........................................... . I

Introduction ................................................ 3 Results .....................................................Conclusions and Recommendations ............................. S

References for Section I .................................... . 1

II SYNTHESIS OF NEW EXPLOSIVES FOR DENSITY ESTIMbTION ............ 29

Introduction ................................................ 29

Fluorination of Tetranitroglycoluril (TNGU) ................. 29

Derivatives of Nitrocyanamide ............................... 32

Fluorination of Dinitrofuran (DNF) .......................... 36

Dipolarophile Additions to Fluor'odini troacetoni tri le

Oxide (FDNO) ................................................ 38

Oxidation of 3,G-Diainotetrazine ........................... 15

3,5-Bis(nitrimiino)-A '-1,2,,4-tr'iazoline (NTZ) ................ ,163,6-Bis (nit rimino)-3,6-dihyd ro-s-tet razine .................. 49

Oxidation of Guanazole ...................................... 50

Experimental Details ........................................ 52

References for Section II ................................... 58

DISTRIBUTION LIST ................................................ 59

DD FORM 1,73 ..................................................... 60

v

ILLUSTRATIONS

] Preparation of Dinitrimino Azo Compounds ................................... 47

2 111 NMR Spectrum of 5,5'-Dini tro-3,3'-bi-2-isoxazoline ...................... 5!

3 13C N'R Spectrum of 5,5'-Dinitro-3,3'-bi-2-isoxazoline ..................... 56

41 Mass Spectrum of 5,5'-Dinitro-3,3'-bi-2-isoxazoline ........................ 57

TABLES

1 Density Estimations for 25 Known Solid Aromatic Explosives ContainingNO.,, 011, a113, and N1 2 Groups ............................................... 12

2 Calculated Group Molar Volumes for Aliphatic Compounds .................... 13

3 Density Estimations for Aliphatic Compounds Containing NO2 , 011, F,

CO2 H, and ONO, Groups ..................................................... 1-

4I Calculated Group Molar Volumes for Various Nitrogen Compounds .............. 19

5 Density Estimations for Amines, Nitramines, and Various Cyclic Compounds .. 20

6 Summary of the Accuracy of the Group Additivity Approach to Density

Estimation ........... ........................ . 26

Density Estimation for Proposed Explosives .................... 27S i........................

v i

I DENSITY ESTIMATION

Introduction

Discussions at the ARPA Workshop on Advanced Warhead Technology

(San Diego, 1974) and at the Naval Sea Systems Command Program Review

meeting (Asilomar, 1974) showed the urgent need to rapidly and inexpen-

sively assess and surpass the massive Russian effort to synthesize new

explosives. The Naval Surface Weapons Center (NSWC), White Oak, is

surveying the Russian literoture on the development of new explosives.

As new families of explosive compounds are identified, their detonation

properties tust be calculated to determine the compounds that offer

advantages over explosives currently in use and that should therefore be

synthesized.

The main detonation property that determines the impulse delivered

by the explosive is the Chapman-Jouguet (CJ) pressure, PCJ' which is

given by:

PCJ - K +l1 (1)

where Po is the initial density of the explosive, D is the detonation

velocity, and K is the adiabatic expansion coefficient of the chemical

reaction product gases at the CJ state. Measurements of P for various

explosives have shown that P is proportional to the square of theCJ

initial density. Therefore, to develop more powerful explosives,

energetic molecules with very high densities must be identified.

The CJ pressure of an explosive ca.n be calculated to within

experimental measurement accuracy by a thermodynamic equilibrium computer

code, such as SRI's TIGER code, or, for explosives containing only

References are presented at the end of Section I

1(

II

C, 1[, 0, and N atoms, by the empirical formula of Kamlet et al. 2 These

methods require only the molecular formula, the heat of formation, and

the initial density of the explosive as input data for a CJ detonation

calculation. The group additivity approach to heat of formation

3,4 ka/o nestimation is usually accurate to within ± 2 kcal/mol; and, since

explosives release 200-500 kcal/mol of energy when detonated, this

approach may be confidently used in detonation calculations for hypothetical

explosive molecules. Reliable detonation calculations thus require only

an accurate method of estimating densities of explosives. One major

objective of this research program was to develop such a method.

The prediction of the density of a solid or liquid explosive with

no knowledge of its physical properties is difficult; no general method

to predict the density of conplex organic molecules exists. Before this

program began, three general approaches to density prediction were

reviewed: potential function, the theory of close packi.g for solids, and

group additivity. The potential function approach is attractive because5

it evolves from first principles, and some recent progress has been

made in its application to large organic molecules. However, as shown6

by Lee et al., the potential function approach is mainly concerned with

minimizing the potential energies for an arbitrary set of potential

functions and then calculating the resulting interaction energies. Den-

sity estimates obtained aF a secondary feature of the approach are

usually inaccurate, and development of an accurate potential function

approach to density prediction would be very expensive and time-consuming.

For solid organic molecules, a great amount of crystallographic7,8

data has been generated and summarized by Kitagorodskii. A theory of

close packing has been developed to explain the measured densities of

solid crystals. However, this crude theory relies on experimentally

measured packing coefficients for each molecule. Although several groups

2

9are working on the problem, no theoretical explanation of the measured

packing coefficients exists. Therefore the crystallographic close packing

approach is not sufficiently developed to use as a tool for predicting

densities of solid explosives.

The group additivity approach to density prediction was usod by

Exner to estimate the densities of 870 organic liquids, lie determined

the densities of very simple liquids to within a standard deviation of

30.003g/cm . For liquids comparable in complexity to most liquid explo-

sives, hie determined the densities to within a standard deviation of *0.008 g/cm3

. Exner concludes that the group additivity approach is

invalid only for liquids with extremely branched chains or directly

bonded functional groups.

No corresponding study of solid compounds by the group additivity

approach has been previously reported. The greater degree of internal

ordering and the possibile existence of more than one stable polymorphic

form make density prediction more difficult in solids. However, because

group additivity works well for liquids and because the other two approaches

cannot be easily developed, the group additivity approach was used in this

study for density prediction in both solid and liquid explosives.

The resulting density estimations for approximately 180 known

explosives and related compounds and for some of the new explosives

synthesized during this research program are reported in the "Results"

portion of this section. Discussion of these results and recommendations

for future work complete this section.

Results

Because the main objective of this research effort was to determine

the general usefulness of the group additivity approach in predicting

explosive densities, an effort was made to calculate group values and

predict densities for the maximum possible number of explosives and

related compounds. For group additivity to be a worthwhile tool in

predicting densities of new explosives, it must be applicable to all

types of organic explosives: aromatic, aliphatic, alicyclic, and hetero-

cyclic. Therefore density data on these types of compounds were collected

il-15from several handbooks. In most cases, density data found in two

or more sources were in reasonable agreement; but for some compounds, two

conflicting density values or only one value from an older, less reliable

source was obtained. Thus some of the measured densities used for

comparison in this report may be incorrect and may result in poor correla-

tions with the estimated densities.

When the available density data for a series of explosives were

assembled, the groups present in each compound were identified and a

linear equation was written in terms of ,olar volume for each compound.

A simple computer program was used to calculate the group molar volume

contributions that produced the minimum total absolute error in molar

volume for that particular set of compounds. Most of the calculated group

values are based on data from 10-20 compounds and are considered to be

reliable, but some of the calculated values for the less common groups

are based on only two or three densities and thus are not as reliable.

In this first-generation group additivity approach, only one value of the

molar volume is assigned to each group, regardless of where it appears

in the molecule. No second-order effects, such as nearest-neighbor

interactions, phase changes, and crystalline structure changes, are

considered when calculati.., these group values. A discussion of the

possibility of including second-order effects in a more sophisticated

group additivity approach, similar to the detailed models developed by3

Benson et al. for the estimation of various thermochemical properties,

is presented in "Conclusions and Recommendations" at the end of this

section.

4 ji

The first explosives to which the group additivity approach was

applied are 25 solid aromatic compounds containing NO2 , Oil, CII3, and NIl 2

groups bonded directly to the benzene ring. Only five group values

(Ca-H1, Ca-N0 2 , Ca-Oil, Ca-CII 3 , and Ca-NIl 2 , where Ca designates an aromatic

carbon atom) are required to describe these compounds. The group molar

volumes that give the best overall agreement and the resulting density

estimations are shown in Table 1 The average error in Table 1 is 1.29%,

3 3which represents 0.022 g/cm based on an average density of 1.692 g/cm3 .

The estimated density is within 1% of the reported density for 11 compounds.

within 1-2% for 9 compounds, and within 2-3.3% for the other 5 compounds.

The use of only one molar volume for each group does not allow for

density differences between isomers. For example, in terms of formulating

high-density molecules, it appears to be much more favorable to have

nitro groups para to each other rather than ortho or meta. This explains

the significantly higher densities of p-dinitrobenzene and 1,2,4-trinitro-

benzene relative to m-dinitrobenzene and 1,3,5-trinitrobenzene, respectively.

There also appears to be a smaller advantage in placing nitro groups meta

rather than ortho to reduce steric hinderance. Quantifying such effects

for all possible nearest-neighbor interactions would result in a slightly

improved overall agreement but would greatly increase the number of group

values to be determined. The good overall agreement between measured

densities and those calculated by using only one molar volume per group

led to the use of this technique in predicting densities of explosives

bound in other configurations.

The second major series of explosives and related compounds consists

of 77 aliphatic compounds containing N02, Oil, F, C0211, and ON0 2 groups.

Table 2 lists the calculated molar volumes for the 26 group configurations

Tables are presented at the end of this section.

5-

found in these compounds. Most of the group values are determined by

comparing densities of 10-20 compounds containing that group, but nine

of the group values (denoted by the letters f, m, q, r, s, t, u, v, and

y in Table 2) are determined from density data on only two or three

compounds and are considered to be less reliable. In the case of C-C,

H2, ON02 groups, two molar volumes are used. One value is used for

nitrate esters similar to PETN in which three or four C-C, H2, ONO2

groups are bonded to a central carbon atom; another molar volume is used

for nitrate esters like nitroglycerine (NG) that have C-C, 112, ON0 2

groups bonded to separate carbon atoms.

The resulting density estimations of these 77 aliphatic compounds

are shown in Table 3. Direct comparisons between the measured and

calculated densities can be made for 71 of the 77 compounds. The average

error is 1.70%, which represents 0.022 g/cm3 based on the average density3

of 1.294 g/cm 3. Of the estimated densities, 48% are within 1% of the

measured densities and another 28% are within 1-2% of the measured

densities. Large errors occur for compounds with bulky or highly polar

groups bonded in close proximity, such as oxalic acid and malonic acid.

In the previously mentioned statistical study of density estimation by

10group additivity in liquids, Exner concluded that the approach is

least accurate for highly branched chains containing several polar groups.

This problem appears to be a real limitation of the group additivity

approach in its present form, but it exists for only a small number of

potential explosives. Second-order effects must definitely be considered

to improve the density estimations for these explosives.

Many other existing and potential explosives are derivatives of

amino, alicyclic, and heterocyclic compounds. Table 4 lists the

calculated molar vo1,ncs for the 48 group configurations required to

describe the 83 amines, nitramines, and cyclic compounds whose density

estimations are tabulated in Table 5. Because nearly all the cyclic

6

compounds considered contain a 5- or 6-membered ring, the group values

with a subscript c in Table 4 are derived from the available density data

on alicyclic and heterocyclic compounds containing 5- or 6-membered

rings. In general, the cyclic group molar volumes are a few cm 3/mol larger

than the corresponding aliphatic groups. In the case of the C-C, 112,

N-NO 2 group (letter k in Table 4), the available density data suggest

that the same molar volume can be used in both aliphatic and cyclic

systems. The molar volumes of two groups found in 8-membered rings

(labeled with the subscript c=8 in Table 4) had to be determined to esti-

mate the density of II, relative to RDX. The molar volume of the group

[C-112, (N-N0 2 ) 2 found in HNIX was calculated by taking the value for

the corresponding group in RDX, rC-112 , (N-NO 2 ) 2 ]c, and subtracting the

difference between the groups (C-C ,iI ) 'hich was determined2 2 c=8'

by the density of cyclooctane, and (C-C , 112) for 5- and 6-membered2 c

rings. This simple difference between a 6- and an 8-membered

ring explains most of the difference in the densities of RDX and IIMX.

33The calculated densities differ by 0.07 M/cmn3 , the measured densities

are 0.094 g/cm 3 apart.

Direct comparisons of the measured and estimated densities can be

made for 72 of the 83 compounds listed in Table 5. The average error

3is 2.054%, which represents 0.0214 g/cm based on an average density of

1.0403 g/cm 3 . Of the estimated densities, 24% are within 1% of the

reported values, 38% are within 1-2%, and another 19% are within 2-3%.

This overall agreement is quite reasonable when compared with the results

in Tables 1 and 3 and when the diverse nature of the compounds in Table 5

is considered.

Undoubtedly there are other explosives and related compounds whose

densities have been measured, but the 179 compounds in Tables 1, 3, and

5 represent those obtained during a fairly extensive review of the open

literature. The group molar volumes listed in Tables 2 and 4 should

cover most other existing compounds. The overall results of the density

*1 estimations by this first-generation group additivity approach for the

7

168 compounds whose estimated and measured densities call be compared are

summarized in Table 6. Of the estimated densities, 70% are within 2% of

tile measured densities, with another 12% within 2-3%. These results and

tile conclusions that call be drawn from them are discussed more fully in

Conclusions and Recommendations below.

Because the major part of this research program was a synthiesis effort

aimed at producing high-density potential explosives and then comparing

their measured and estimated densities, the group additivity approach

was used in Table 7 to estimate the densities of 11 compounds that were

proposed targets of the synthesis program and one can pound that was

recently synthesized at SRI. Efforts to synthesize the proposed compounds

are summarized in Section II.

3Tetranit,3glycoluril (TNGU), which has a known density of 2.03 g/cm3 ,

was used to obtain the group molar volumes required for density estimations

of compounds 4, 5, and 6 in Table 7. These group molar volumes are in-

cluded in Table 4. Furan, which is compound 51 in Table . is the base

compound for tle first two compounds in Table 7. Conpound 3 in Table 7,

discovered at WVOL and recently rodiscovered at SRI, has a measured density

3of 1.85 g/cm

Conclusions and Recommendations

The main conclusion regarding the applicability of the group additivity

approach to density estimation is that tile results are very promising.

Approximately 180 explosives and] related compounds of very diverse natures

were considered in a first-generation group additivity approach, and almost

all the estimated densities were within 1% of the measured densities,

33.3% were within 1-2%, 11.97o were within 2-3o, 8.9% were within 3-1%,

and 9.0% were more than 4% different from the measured densities. A 3%

error in the estimated density of an explosive that has an actual density

3of 1.7 g/cm an a CJ pressure of 300 kbar would cause an error of

8

approximately 18 kbar in the estimated CJ pressure, because pressure varies

as the square of the density. This 6% error is within the experimental16

error of present methods of measuring the CJ pressure. Therefore, an

error of this magnitude would not affect a decision about the usefulness

of a new explosive molecule based on a CJ pressure calculation. Of the

densities estimated in this study, 82% were within 3% of the measured

density and thus would yield realistic estimates of the CJ pressure.

The average absolute errors in density were approximately 0.022 g/cm3

in Tables 1, 3, and 5 and may be a better indication of the accuracy of

the group additivity approach than do the percent errors. The absolute

error in density exceeded 0.04 g/cm3 for only 24 of the 168 compounds

(14.3%). Therefore 85.7% of the estimated densities could be used with

confidence in CJ calculations.

As mentioned previously, the largest errors occurred for compounds

with several bulky, highly polar groups in close proximity and for compounds

that contain groups whose calculated molar volumes were based on density

data for only two or three compounds. As more density data become avail-

able for a certain group configuration, tie molar volume can be determined

more accurately and the overall agreement between measured and estimated

densities of compounds containing that group improved. Therefore, it is

iery important to obtain as much density information as possible for a

series of related compounds before deriving the group values.

10From the results of Exner and of this study, it can be concluded

that the group additivity approach estimates densities of liquids very

accurately, except in a few cases of very highly branched, polar molecules.

Group additivity is therefore a useful density estimation tool

for the many liquid explosives that are known and those that will be

synthesized. Inclusion of second-order effects, such as correction factors

for nearest-neighbor interactions, should reduce the errors in density

for the highly branched polar molecules.

9

The group additivity approach also worked well for solid explosives

when the group values were determined from data on many similar compounds,

such as the aromatic compounds in Table 1. Slight differences in the

crystalline packing geometries of these compounds were effectively averaged

over as the group molar volumes were determined. In compounds that are

not as cimilar as the aromatic explosives and in compounds that have

several stable polymorphic forms, the difference in crystal geometries

could have significant effects on the actual density. The first-generation

group additivity approach used in this study cannot predict these density

changes. However, inclusion of second-order corrections for the various

possible crystal configurations may allow group additivity to successfully

predict different densities for various polymorphs of a solid explosive.

Based on the accuracy of the group additivity approach in predicting

densities of liquid and solid explosives, and based on the need for a

reliable approach to density estimation for hypothetical explosive molecules,

it is recommended that the group additivity approach be extended to include

second-order corrections for phase changes, nearest-neighbor interactions,

effects of crystal geometry, and other factors. Together with a CJ

calculation technique and a related synthesis program, an expanded group

additivity approach would constitute a rapid and inexpensive method for

selection of more powerful candidate explosives.

1

10

REFERENCES FOR SECTION I

1. M. Cowperthwaite and W. If. Zwisler, TIGER Computer Code Documentation,

SRI Report No. Z106 (March 1974).

2. M. J. Kamlet et al., J. Chem. Phys. 48, P. 23, P. 36, p. 13, p. 3685 (1968)

3. S. W. Benson et al., Chem. Rev. 69, 279 (1969).

'4. R. Shaw, Int. J. Chem. Kinetics 5, 261 (1973).

5. F. A. Momany, et al., J. Phys. Chem. 78, 1595, 1621 (1974).

6. T. W. Lee, R. A. Greenkom, and K. C. Chao, Ind. Eng. Chem. Fundam.,11, 293 (1972).

7. A. I. Kitagorodskii, Organic Chemical Crystallography, Translation

of the Consultants Bureau, New York, 1961.

8. A. I. Kitagorodskii, Molecular Crystals and 1M1olecules, Academic

Press, New York, 1973.

9. 11. Cady, LASL (private communication).

10. 0. Exner, Collection Czech., Client. Commun. 32, 1 (1967).

11. Handbook of Chemistry and Physics, 53rd Edition (1972-73), Chemical

Rubber Co., Cleveland.

12. Engineering Design Handbook, Explosives Series: Properties of

Explosives of Military Interest, AMCP No. 706-177, U.S. Army Materiel

Command, January 1971.

13. B. T. Fedoroff and 0. E. Sheffield, Encyclopeoia of Explosives and

Related Items, PATR 2700, Volumes 1, 2, and 3, Picatinny Arsenal,

Dover, N. J. (1966).

14. N. A. Lange, Handbook of Chemistry, McGraw-Hill, Now York, 1961.

15. T. Urbanski, Chemistry and Technology of Explosives, Pergamon Press,

New York, 1964.

16. W. C. Davis and D. Venable, Sixth Symposium (International) on

Detonation, ACR-184, Office of Naval Research, Pasadena, California,

1970, p. 13.IIr

.. . . ... . . .. . . . . .. . . . . . : . .. i . . ..1 1 t . . t

- - -t- .- 0 t -N - -o - -000--- - - - -. .- 0

00~0 0 00 0 0 6O 0

N~~~~~~ N N Ct a> 0 0 0 > t o t t . 0~ . t. I t.

.. .. .. . . . .C> C . N. . .N .t. t. . . . . 0

o~~~~~1 -- - -1>>0C -N 0

41 v. 00 v o? - - O 0 o o ON N 0 to N taN 00 ON N- --c Na N cC v. I . N

to 0C o o o

C>u

12to

Table 2

CALCULATED GROUP MOLAR VOLUMES FOR ALIPHATIC COMPOUNDS

Calculated cm 3

Group Configuration Letter Designation Molar Volume mo

C-C, H a 30.68

C-C, H2 ,NO2 b '2.61

C-C 2 ,If2 c 15.69

C-C ,INO, d 29.16

C-C(NO0 ) e e 73.60

C-C , 1, (NO2 ,) f 59.12

C-C2, (NO) 2 g 40.87

C-CO,=O h 21.88

C-CH 2 , ,0 16.84

C-C ,012 ,O1 29.61

C-C, If ,F k 30.68

C-C 2 IHOH 1 15.12

C-C 3 ,OH 1.94

C-C,=0,OH n 21.98

C-C ,H,=C o 12.11

C-C ?If2,ONO 2 (PETN) p 34.41

C-112 ,=C q 20.05

C-C ,F2 ,NO2 r 59.92

C-Cs2 fF S 25.63

C-C ,F3 t 46.28

C-C,F,(NO2 ) 2 u 68.81

C-if2 ,0' v 27.91

C-C ,H, ,ONO,, (NG) w 51.21

C-C4 x 41.49

C-C3 ,NO. y 71.23

C-C 2 ,H,ONO- z 40.39

13

0 w t- CD 0 wD C 0 0 m t- OKt- 0 CC 0- to -T O D

:1 4 0 r-4 .-4 010C C .") 4 0 0 0 000 .-4C

LtC. CC vD o, CD 1 0 0 CC CD 0' oC4 00 K. 4 v 10 0 IT- 0

cz44 NC NC CCC 1, 0 MD w D t'-

.0 U - 00 to 00 mC tD0- N 0C to QD '-4 t. 040C D

-1 a" C! 0 C Ci 0 10 a'- 10 K' CC. -4 -! CD CD t- 1D K'

o-H -4 0 0 v- C 0 0 1 4 14 - 4.4 0 00 -4 0

(0

0

a0 0 w I'- 0 l 0 4 0C .1 m = CC CC wD wD 10

CD C CC CC C! C CC C CC

mC C"C VD tD CD 0 1 : C- CC CC N0 0 C CC C 0 10 (n CCm' D M1 CC CD v 0 C 00 0 -4 1'- to t'- K- co CC

:% + + + Q~ + C) w 4+ + 7 + C

0C 0 . 0 . + + ~ - ) + + . " C) + '0 +m.. + + + + C .0 0 dU + + .0 U +e4 + M ' C

a OC C C C% CU CC CC CC CC CU 0CC CC 0 z0 z NC cl 10

z

z

E CC C' oo CD ,- CC CD CD LO 0 1 0 1l)0 0 CC 1 0 00Cz :j 0I o K- -11 oo CD CC CD to CD to 0 CC 00 C 0 CD CD CD

CU 00 C C a CC CC qD CC CC 1 CC! 10 10 .-4 CCC' CD 1- . '

0'. ~4 .4 0 0 -4 V) 0 .'4 4 .-4 ,-4 . 0 0 0 ' 0

0

00

4: C' C C CCC 10 C C CC CC CC 0! C : K '- 0 0 CC C

a') 10 6 C l 10 -4 CC 0 0 10) 0 IT IT v D l 10 .4 CD 0 0 10n C

0 -. t'- CD 01 CD) 0 CC 0 0 C13C 1010 10) 1CC D C D to 0 '

o) O1.4 -4 m- 10 .4 .4 .- 4 14 1.4 ,-4

10

00

0 Q 0i4 E! W.) I) I~ I) QC I 0 0l . 1 ,

z ) 10 C) 0

.U CC 10 10 C '- CD CC 0 u C 10 UD 10 CD K' C

14

0lIn t. 0)i 0a to CO C, in) a) )C)3 M t- a) C') M- CC 0 ~ CC C r- 0 C! ot 0 - in C C

0 0 0 0 0 0 -1' 0 -4 0 w0 .4 - 0 0 0) I

S00v C') 0) t- I,4 wC CC t- i 0 Cl) C' 0) N- 0m nv) tA o C .) cq vC CC 0 .in C ) .- 0 mC '

C) 0 0 .4 0 0 0 N) .4 ~ . 4 . . 4 . ~ ..

0 0

0 fs0 t - QC to M0 N0 0 in CC C ) WCC C - i 0 C-1 - > C . 4 en 0 00 CC C) £0C 0 t- ' C

0 S . . t: . . ) CC 1;- 0 n . i -c -UL m ) in C . C- C) C n -4) £0 £ i13CC 0 0 C-4

U 04 . 4~

0. 0

0 -03

C..~ ~ + a'- -= C C 0) - .

CC -+ + + 0)i + + C) +z - W Q + C C) N r c C N N C) +) +C

0 cq +)+ C ) 0 Cq 0 ) 0 ) C + C) + +CC) 0) C C', + + 0) +i ;j - + C - ) C )

I~. + C) + + C)4)C 4 ) C ) C )C0 Cd ca c s N)0) 0 03 C ) 0) C') 00 C 03 N) 09 N N 0) C

0 t

0~ 0)0 lI40 0 0 0 C3I

-l .4 c) t ciL

m. .- C 0 0) C C) 0 in .4 0)0 £

0 to C) C C)! 0 - C) 0) CC 0 i 0! 0) C0H OD 00 00 . 0) 0 H M- 0) 0 W in C 0 0 in

o). CC CC C'3 CC CC Cv 0 i C C) 0 0 0 0

CL

C.. I Iu U .

0 0)

.. 4 C)~ ~~~~~ C -. CC CC C ) 0 . ' C 0 £ C - CC 0 .4 I'-LO G~ P4 -CI M v4 0 0 CC t.

C4 0qc

C..5

r mO t, to ei) cc m~ . a ) c c C c c V- C 0

p V) OD m m 0 a) 0- mO 0' cc 00 t- mO N- LtC COO CI "IL

oi 0 -v '? N v v -T 0 0 -T 0 R 00 0 0 C) CO) 5'

2;t 1 z 0iC 0 t 4 14 CO C ': CO C; cc t: CO ccS. CO t- wO 0. Mc 0 vC to Q 0 n 17 t, K-) CO C- t- t- 0 0 0 K-

o C C 03 C1 N CO m O V 0 ) 0 NO C 0 N- C - -c N- 0 C CO N

0C

0 a. N r .t 0 0 ccK0 0 C c C 0 fO od ri +O 0 4 +O +O a )mC 00 ' 0 u- 0 -4 +- +4 N 0 CO O 0 C ) CO c

Ct) .. CO a cc 0 Q O C C ) i c 0 +O + C es 4 c +- +- es C +o1 coC 0 C') tN CO CO O N -. N C N N N - N - N .-4 0 0 .

0~C-

40

z

U) t, oo +0 + t- +q L- to + + 4- .

ovCC C l) t, C) ) V) 00 m4 4 0 C) +0 (D 4 m- 4I 03v (1C 44 m to (D C 4- ( + N C) .0C) C )

CC3 C) 4- +: 4- 4- + 4- 1C0 C C C C - C N 4 C 1

0

o (d

V C) K- 0 C O a) K- CO C O -4 c CO C - - cc K C C4 0) 0; N* N

) - to~ t, CO CD CD O V . CO C 0 Co CO 0 0 CO N 00 K-K o K- 0 -,r 03

I! u0 CC0

.in c c u- uO uO a) L) V - C - C O V V c C c Cir

4 N N N N 1O it NI . N N N i v 4

C) UC L) K- L) 0 u4 0 NO N' m 8O 0- C O C Nv0c ) C c

u CC u I

pu ou 8 a8o MU0 A =

I I I I I 4.. I

0 'V 00

CCC 0 0 8 8 0 0 O 'CC

Ir to '0" to COO 00-0

CC C C C C CC CC CC 0 I I 06

0 C 0 C4 0m0 C) 00 cc t'o* 0 -

~~s.IO (D -' ~ 0 ' ~ 0 c 0 t - t,

'.4 (0 -1 0 0 00 4 00 0M

w4 -4 00 0 In mi - O 0 o t

C. '. . '4 '4 - . '4'4 '4 4 -

U

04 0 0 0l) a O C1 0 -to 0 0 0 m. C N '.4 (n3 00 N w vc m' C) to ~ c 0.4 0 M . . .

0 S. (n t.- OD 0 t- t- t- ' ( 0 V CC 0 N~ .4 '4 '. '4 . '4 4'4 N '.4 '. '4 CO )

0 00.

0

< N> + '

:0+ t + CO)14 xO ~N N . + 0. +

0 0.)~+ + N' + + 4 0l 0.0 E + x 0.0 a , h + B. + >~ + + cc

0 0 + B, c) C) + + C' c 0 . + 4- a.. - 0 + + + CL 1 -. + ' .4 + .

. 00 C4 . 0 N , C N 0 U N 0 N

0 0O 0 L' m to v'0 0 0 S O ' 0 0 '4 10 C ~ 0

0 4

'0 0 0 0 N O 0 0 0

0 F-. 0 M0. lii M 'A1 D C - 0 0 .I

r- 0 m , MvU)C.4 m*.A

0 NtC)i8 .4 Nl to4 al 0 00. c 4 N 0 0 0 0.0 0 0 0.

-. 0 ~ cl n '.4 N Nq N- v N '. N1 N1 0 1-0 c2000a00e

:0 v 0 0 000 0

I. S..

<~ V.. >> 000000

z0 0

0N0

L)0 0

w- 0 140 u40 Q 01 0 0

U 4 00:0

Y- 0 : 0

-~ ~ z 04 *O 1 0 4 I - 00 0 40 :0 0 14 u

0 00. p NZ U 0 ' p. , IN~ = 0 = OZ I0 . 4, 0 = 0 N V 0 =~ U 0-00

0 C,0 0 1

0 I0 N, N4 0 00 . v .-. :0 0 0 40 0 0 ,

I -) 4 4 4 , 4 I 1 I 10o 4, 0t '. 10 0 0 0

I 0 Z 14?. 14 'I 1007 I 0 4

Table 4

CALCULATED GROUP MOLAR VOLUMES FOR VARIOUS NITROGEN COWOUNDS

Calculated

Group Configuration Letter Designation Molar Volume cm3 /Mol

C-C, 112 ),1\2 2 34.67

C-C 2 ,tNH 2

22.49

C-CI 2 ,NH 20.64

C-C 2 ,H, NI 8.42

C-I , NIl e 32.87

C-C, 11 2 , N 16.09

C-113 ,N 0 31.00

C-C, H2 , N-N0 2 27.30

C-C 2 ,H,N-NO2

9.70

C-t , N-NO 2 p 37.46

[C-112 , 0,NNO 21C or 28.02

C_04 T 28.45

C-1IO3 p 26.63

C-ii2 ,10 2 v 28.66

C-CF,(N02 )2 * U 65.83

C-C,O,F 2 26.78

I

C-C 31,, 2.9,

(CC 2 1 I 2 )c ca 18.38

[C-112 ,(N-NO2 ) 2 ]Ct eb 41.60

(C-C ,12)c=8 -" 16.80

(C-1i 2 , (N-N0 2 ) 23c=8 40.02

cc 21.75

(C-C,1 2 ,0)c

(C-C,ll,=C)C cd 15.12

(C_1,O,= C)c cc 20.,66

(C-11, = C, Nl) c cf 19.81

(N-C,It,Nil)c eg 11.45

18

,

Table 4 (Concluded)

CALCULATED GROUP MOLAR VOLUMES FOR VARIOUS NITROGEN COMPOUNDS

CalculatedGroup Configuration Letter Designation Molar Volume cm3

(C-l, =C,N)e+(C-H, N,=N)c ch 46.27

(C-C,H2,Ni1) c ci 22.35

(C-C2,=O)c cj 13.44

(C-C2 ,H,NO 2 )c ck 31.58

(C-C2 ,H,OH)c cl 12.17(C-C'l) cn 24.67

(C-04 )c cn 11.63

(C-NO2 10,=C)c co 33.53

(C-C,F,=C) cp 20.21C

(C-C, U, O ,N0 2 )c cq 36.04

CC-C0, (NO2) 2]c cr, 43.56CC- (N-N0 2 2, =O C cs 36.66

[C-C,Il,(N-NO2) 2 ]C ct 42.68

[C-C,F,(N-NO2 ) 2 3] cu 47.77

CC-F 2 , (N-N02 ) 2] C cv 51.78

(C-C2,=N) c+ (N-O,=C) c cw 15.92(C-H,C,=N)c+(N-O,=C)

c cx 28.28

(C-C,N,=N)c+(NC,=C)c cy 11.82(C-C,O,=N)c+(NO,=C) cz 20.38

CCa-N(1C)*4f

20.38

Ca-N(C C) 8.54

CaN(C ,NO 2 ) 21.66

*Th groups was listed in Table 2. Consideration of more cOMpoundscontaining this group has resulted in an improved value of its molarvolume.

iSubscript "c" denotes a group from a cyclic compound containing a5- or 6-membered ring.

tSubscript "c=8" denotes a group from an 8-membered ring.

**As in Table 1, C a designates an aromatic carbon atom.

19

01 CO 0)) t, w m) v) wCN C - ' O C O 0 v4

c') 0 4 3 0 0 0 m v- N -i C lN

q4 to 0) CO CD to C 0 m' CO 0) w 0 0 CDNv. . CO)rlC CO tr co U0 V) MO CO CO M4 vO C O C 0 00

OV 0 00 00 0 0 00 0 0 0 -i 4 00

to

z

0 C

4) V

3 00 v V' CO) N CO) cli N C) -v v CO 0 N D CO C 0 CO COv > C! CO 0 1.. C- CO 0 C- CO C- C- t' 0 " CO CO CO CO C

- ;. CD t'- CO 0 Co (7) w~ to N CO Co CO 'r 0) CO 0 N N 0.. s tC Co o CO C 0 CD C) CO CO) 0 Co ) CO CO C 0 0 CO O

0

C4 03

N1 + Nq N9 N1 1CO .~ .N. + + NC

CO U l 0 + u 0 9 0 C.) C 9 eq 0 + + 4'0) Na) O N N N - '. 0 Q-

O +' 0 ' CO CO CO ' 0 q l 0 0 -) eq +C4+ + + .O 0 :~ IOCL (d u) CO1 cl ol vq C l) C 1 CO 0 3 C'- -T 0 C CO O 4 cu

C) vO CO C- (n C C 0 CO t- t CO It.4 N ) CO CO) -:1CC>. CO C O C - t- ' ~ CO C'- 0' M' t - 0 01 0) 0o C)

Cv4 0 0 00 0 0 0 0 0 00 00 0 v.4

vI - -

U)

(- C;. .W CO C C ) Cl V ) C) ' ) 0 CO C) C O C) )C

a) ) Co C'- 0'. CO t- C- 0 0 - C N 0 0 0 0 CO) COC

zzu L

u I U

, N N N (4 N

v Z - U UI u U

Q. 0 '4 - -0- - Z -' I , '0; C; 0 I N 0 N

N I N N Z N N ~~ N N N20

01 C') N' t. wO C 0 C) - O )C

~I0 0 to4 w. 0' -'CO CO 0 - 0 V4 N

4' >.04 C- 0 ) 0 C) 0! 1 C i 0) 11) C)

0 %. CO CM 0 t, 04 0- OD C O IT Lo t- 0 '' 00 t-.0 Co 0 %. 0- C-) V. CO m) C') 0 A ) %- t - 4 m ' C)

C% 0 0 0 4 0 0 0 N- N. '.4 0 'A .4 .4..

E

to

+ +,CL 00 Q' 0 ' O C O C) C- 0 C)00 ' 0 0 0q

0 -4V O C ' C) C -4 (D (n C1 NO v- cli + C13-3 0 .)+ . . . . . c

S. - CO 0 C3 C3 0. -4 +O C- k~ C4 C3 C, C' t4COC-C-w 0 C) Cl C) CO) to cl ci C') N- -4i ci 03 CO N 03

0:

EIto +;+2%.

S 0.0 O., to t, to t- C l) %+ m t to 03 IV (D C') 00

Cs ~0 C') CO 1 O 0 C' 1 C C O C') C'! CO C) ' +co 0.) 0~ 0 0 0 0 0 + 4.

00 (D 00. v) a) (n 00 CO CO 0 C ' C) C ) C'1 C))bb CO

o4 wO :1 v t -C)

4-

0

- C)0 CO CO v. O - O C

CO u.. C) zO C O C ) 4 C 0 CO I) 0 0 C 0C O

IV 0:

C)l

0:21

C D 0 1 1 t'C- C C ' 0 D cD t -

94 03 C'4 03 -' N ' D 0

Ii 4 0 -. 0 to. 0 40 0t, 00 M m

C)

't 0 D CD w 0 0 0 00 to 0'0 ) cO) N c to 00 C

W) > 0! Ci 0 c ) cCi )

0i 0 0.- N ~ 0o 0' 0 0 00000 0 0

0

0 ZuD cc ID z' <v C ' c

00 01 - 0 c0 + o~ c c -4 0 D C

a4 CDj T1 CD 0' .- 4

0 + I cs

00 020

0 I a U) 0

Z,~~ ~ ~ 0 :+ 7 C + 'jr

0 7

+ u C, 0 + .+

Fr CI 0 +~ cl) N C

+ L..J + + 1

1.. cc . 0 n r + 0 cli u C o+- o + + (9 CD - 0 +Z

00 0 v 03 N C3~4

Il e q 0

u' CD D .4

0 a) .l .40 0 + l a) c l

00 + -w z 0 4 U) +q 00 00 to

M 0 g 0 00 t + +

-l CD oocc C 0 a) a) 0) 01 0 CD C0 D0

0 0 0 0 .0 1- 0 ) CD g + + l

-T (*. C) N) (D. (D s.D. v -V N -T 0 0J C )

I!0 C'

u a)t N W0

N C

0) C) C r:C ') 00'

a ' 44 C m 0 CD rD cc c C

u 0 1

1to

E-22

0 000

C)l

0)Cl O. c 0 Cl) 0-- C13 0 cl t- 0 0 00

C Cc C')CO0

C3 0)0 )0050 4 (D C.Oc

0s 0 0) w t- 00( oOC.) o

0

+ +Ee:K 4.4 C)

= + ~ +. + 0 +Occc

0 'cd 0) +) cc +cc-n c- 0) CC' a. c ci

0

-'

zM a

C) z

:4 0

C, . SD t-~ t- 40 00E- a) oo 0D oo t- 0D 0

LO 0 0 0 .4 to

54i

If) 0 .-4C') 0cc2C

00 C) 0 '-4

1.; Ci 0 0- C

0- 0o 0 0 0N -

U 0 EIZ0

ol U

I..~ cd V ccc 0 0cc

0 v3. vc IT C13 03C-

.0 cc0 e

cd t4 04)4 ~ 4

z~~ ~l UC) + C 53C C C

z a, 00c C'0 o) co m

Wc 0

.00 0ICC> 0 - ' cc

0, 01,

(D 0o 0C ('C wC to

cc 24

csO ) 0 0nw C) k

es. Z4 0 0 4 .- . 0 CO -1 0 n 4O -4 4D

*0-j

CO 0) 0v) 0 wn 0. U.-- 0) 011 O C 0 O 0 . C'- S O CO

0 ) C t O w O CO C- CO (C tO C- 0 0 C-

4)0 Cd4% 0 0 C -3 M ~ 0 1 1 0 3 4 0 0r 4 '-4C '-4

C.)

CL

C-~qc 0 0) 0. O 0 O S ' 0 C 0 0

+)C C O Sn CO -'03) C- 13n 0 CO3

z) "iCi)l n t

0 ~ ~~~ 0 4' 1 'a CL 4' CO C01CC

44 * ) ' 0 C) "4 .4 C)0 0in E 0 0 0 Bt CO C O C C) 0 1* . ..

o 0v D 0' 0 0 mO CO NO >1 01 01 0 1 0

0C 00 01 0. o. o. tn 0 0 9 c 0 0 1 C) ,,,,

t C 4C'C4. 'C'C'C"

0~ Z0 0 40 oC0o0O 00

C) En 0. 00...0

.0 C1 (0 (D q 0 S0 co Sn -''-N0 0 0 00m

- C 4 00 V -M - 0 0 N.- 0 N 4 t -4 w -MD . 0 C

it m) 0(1 I- toC) C) C) C) U O

0 0

01 C CO 0 0 CO C Zn S C n C

0 z zS DE S

CO .- 0 C- CO j -4 . -4 Sn L .i- - OC 03

C; c'; N N?. 0;

tN No 0NN 00 00 ri0

0 0 NO ~O N C N5

Table 6

SUMMARY OF THE ACCURACY OF THE

GROUP ADDITIVITY APPROACH TO DENSITY ESTIMATION

Number of Compounds

within This Range of % of Compounds

% Error Range Density Estimation Error Studied with This Range

0-1 62 36.9

1-2 56 33.3

2-3 20 11.9

3-4 15 8.9

4-5 8 4.8

>5 7 4.2

Total 169 100.0

Average Density (179 compounds) = 1.241 g/cm3

Average % Error (168 compounds) = 1.784 %

Average Absolute Error in Density 0.022 g/cm 3

26

Table 7

DENSITY ESTIMATIONS FOR PROPOSED EXPLOSIVES

Molecular Groups Calculated Calculated

Compound weight present molar volume density. g/cm3

1. NO 2 ()N 2 158.07 2cd+2co 97.30 1.6246

0

2. NO2 O 194.05 2co+2cp 107.48 1.8055

NO2 NO2

3. r 340.16 cn+4cc+2cr 185,75 1.83130, 0 (Measured Density 1.85)

O f 0(1.01l Error)

NO2 NO2

DTGU

NO F N02N N

4. 0 358.09 2cs+ct 168.85 2.1208

NO2 F NO2

TTGU

NO2 F NO 2N N

5. F2 /2 402.08 2cs+2cu 178.65 2.2506

NO2 F NO2

NO NO2N N

6. F 22 36.10 2cu+2cv 16.72.1137

NO2 NO.

0II c " )7. F(N02 )2C-C"12-C-OC12-C(N0 2)2F 318.10 c+sh+i+2u 186.07 1.7096

27

Table 7 (Concluded)

DENSITY ESTIMATIONS FOR PROPOSED EXPLOSIVES

Molecular Groups Calculated Calculated

Compound weight presene molar volume

8. F(NO 2)2C-CH2-CF2-O-CH2 -C(NO 2 )2F 3,0.10 c+x+2u+( 190.97 1.7809

9. F(NO 0),,C-CN 314.07 2u+cy+cz 163.86 1.9167

C(NO ).,F

10. F(NO)CC--N 238.09 u+ck+cc+cw 136.17 1.7.185

" .1oCHI

NO,

11. F(N02) 2 C- % 238.09 u+ca+cq+Cw 135.08 1.7626

N -O2 Cll

12. 0-,N N..O 230.14 2a+2cq+2cw 10.68 1.6359

(measured Density - 1.686)

(3.12 ' Error)

See Tables 2 and 4 for defin t 1onS.

28

i

I

II SYNTHESIS OF EXPLOSIVES FOR DENSITY ESTIMATION

Concurrent with our research on the estimation of density by group

additivity techniques, we conducted a synthesis program with the objective

of preparing specific nonhydrogen or low-hydrogen explosives and

determining their densities. These explosives were new, and for the

most part, their syntheses were of an exploratory nature. The choice of

compounds to be synthesized was made by agreement among the Project

Monitor, Dr. M. J. Kamlet and Dr. H. G. Adolph of NSWC, and Mr. C. L. Coon

and Dr. D. L. Ross of SRI. Although none of the target compounds had

been prepared previously, most of the synthetic steps were based on

known analogous reactions. However, this research should be considered

as an exploratory synthetic effort in which the goal was to prepare new

and potentially important military explosives.

Fluorination of Tetranitroglycoluril (TNGU)

Tetranitroglycoluril (TNGU), discovered by the French, is a

powerful oxidizer that is currently receiving some interest in the United

States because of its high density (2.03 g/cm3 ) and high oxygen balance.

One detracting feature, however, is its sensitivity to moisture. Because

a fluorinated TNGU molecule was expected to have a higher density and/or

lower moisture sensitivity, its synthesis was investigated.

We proposed that fluorine could be incorporated into the basic TNGU

structure by two methods. First, TNGU might be fluorinated directly with

29

Ft. . .

elemental fluorine to replace bridgehead hydrogens and give difluorotetra-

nitroglycoluril (DTGU):

NO, NO2 NO, NO.I H I I-F I-

N NI N N

H N F N

NO2 NO,, NO, NO,

TNGU DTGU

This reaction should give a product with increased density as well as

provide a nonhydrogen explosive, a class of explosives of current

interest. Precedent for this type of reaction at a tertiary carbon is

found in the work of Hesse and Barton.' The density of DTGU, estimated

previously in this report, is 2.12 g/cm 3 .

Second, the carbonyl of TNGU might be replaced with difluoromethyl

groups by reaction with SF4 to give 2,2,5,5-tetrafluoro-,3,4,6-tetra-

nitroimidazolido[4,5-d]imidazoline (TTGU):

NO, NO. NO2 NO,

N N N NSF4 F(2) F F

N N N NI I I INO2 NO2 NO2 NO.,

TNGU TTGU

The success of this proposed reaction would provide a more dense explosive

-(estiimated density is 2.11 g/cm3) with lower moisture sensitivity than TNGU.

30

The closest analogy to this reaction is given in the work of de Pasquale, 2

in which a disubstituted amide is converted to its difluoromethyl derivative.

The reaction of TNGU with elemental fluorine in HF was studied in an

effort to fluorinate the bridgehead carbons. A typical reaction was run

by dissolving 1.0 g of TNGU in 25 nil of anhydrous hydrofluoric acid in

a Kel-F reactor and cooling to -780C. A mixture of fluorine in nitrogen

(1:4) was bubbled through the solution for one hour. A sample of the

reaction mixture was removed, and the fluorination was continued for

another hour at O°C. Removal of the hydrofluoric acid by entrainment in

N, left a mixture of white solid and yellow liquid in both the sample

withdrawn and the final product. Although a 19 F nmr analysis of these

crude products showed a peak at 150.6 ppm upfield from fluorotrichloro-

methane, the 1H analyses indicated that the major portion of the product

mixture was TNGU. After multiple recrystallizations from acetone, a

very small amount of another product was obtained. The elemental analysis

of that product was very close to that expected for dinitroglycoluril.

Since dinitroglycoluril might be expected to arise from extensive handling

of the product mixture under ambient conditions, the fluorination was

repeated on a larger scale, taking care to limit exposure of the reaction

mixture to moisture. The 1H nmr analysis of the crude product again

showed that the major component of the product mixture was TNGU.

One additional attempt was made to fluorinate the bridgehead carbons

of TNGU, using perchlorylfluoride. 3 Ethanol was used as a solvent.

Column chromatography of the product resulted in f'ractions containing

mixtures of unknown products, which all contained ethyl groups according

to 11 nmr analysis. Although TNGU exhibits some hydrolytic instability,

it was hoped that reaction with the ethanol would not occur.

The fluorination of the carbonyl groups of TNGU, Equation (2), was

studied using mixtures of SF,, and HF. The combination of 1 g TNGU,

31

7J!

21 g SF 4 , and 19 g HF was sealed in a high-pressure reactor and heated

to 1000C for 4 hours. A dark, gummy product was obtained. The ir

spectrum of the product did not resemble that of TNGU and did not appear

to have any C-F absorption. Apparently, TNGU decomposed under the reaction

conditions.

In summary, the fluorination of TNGU with elemental fluorine or

with SF 4 appears to be difficult. Future work in this area should

be directed toward replacement of the bridgehead hydrogens to TNGU with

elemental fluorine or another fluorinating agent. Although we obtained

no definable fluorinated product from these reactions, TNGU was stable

under most of the reaction conditions used, and a small degree of

fluorination was detected by nmr analysis. Furthermore, the nmr fluorine

shifts were in the region expected for a fluorine atom on a bridgehead.

We would suggest the use of much longer reaction times and perhaps the

use of a fluidized-bed fluorination technique to study this reaction

further.

Derivatives of Nitrocyanamide

The nitrocyanamide group [-N(N0 2 )CN] is of interest when considering

the synthesis of new energetic compounds because of its favorable heat

of formation, the fact that it contains no hydrogen, and its expected

contribution to increased density. Although this group has been known

since 1949,4 very little work has been done on the synthesis of its

derivatives. The only two procedures reported for synthesizing the

nitrocyanamide group are by the reaction of cyanogen halide with the

salt of nitramine, 5 Equation (3), and by the reaction of a salt of

nitrocyanamide with a reactive halide,6 Equation (4).

32

Na CN

R-N-NO + CNX - R-N-NO 2 + NaX(3)

X =Br, I

CN CNI IAgN-NO, + R-X --- R-N-N0 2 + AgX

(4)

X = Br, I, C1

The latter reaction, which was studied briefly in our laboratory,

appears to be quite general with aliphatic halides, and derivatives

such as the following have been synthesized:

CN CNI IqCH3N-NO,, CH2 =CH-CH,-N-NO2

OH3 CN CN

OH-N-NO, CGH 5-CH2 -N-NO,

CH3

CN CN CNiI IS3H 2 N 2 NN--0H-CH=CH-CH,,-N-NO 2

33

Silver nitrocyanamide is easily prepared from nitroguanidine by an

improvement of procedures developed by McKay4 and Harris

NNO 2 AHNaOH II NaNO?

NH 2-C-NH2 + CH 3NH2 (5) CH 3NH--NHNO 2 (6)

NO NHI I 1. NaOHCH3N- C-NHNO2 . AgN(CN)NO2 + CH 2N 2

2. HNO3

3. AgNO3

(7)

On this project we studied the chemistry of silver nitrocyanamide

with the objective of placing three nitrocyanamide groups on a triazine

ring:

ON CN

Cl N

C.oN > ",N N " N

i+ 3 AgN(CN)NO, (8) + 3 AgCI

OlN Cl NO- No N-OI INO2 NO2

As part of this study a solution of excess silver nitrocyanamide and

cyanuric chloride in acetonitrile was stirred at ambient temperature

for 48 hours, during which time a small amount of silver chloride

precipitated. The silver chloride, which was collected and dried,

represented about 4% of that expected for complete conversion, A

34

second reaction of silver nitrocyanamide with cyanuric chloride in

acetonitrile was run at reflux temperature (820 C). After 24 and 48 hours,

3% and 5%, respectively, of the theoretical quantities of silver chloride

had precipitated. Similar reactions were tried using anhydrous acetone

as solvent, and very little silver chloride precipitated. A workup

of these reactions yielded only starting materials, and no metathetical

product was detected.

We also briefly examined the reaction of picryl bromide with silver

nitrocyanamide to obtain the picryl derivative shown in Equation (9).

NC NO2

Br N

02N NO2 02N NO2+ AgN(CN)N0 2 (9) + AgBr

NO2 NO2

The results of this work were similar to those with cyanuric chloride

in that very little reaction occurred; only small quantities of silver

bromide were formed even after long reaction times or at elevated

temperatures, and no metathetical products were detected. In the case

of picryl bromide, the lack of product might be explained by the size of

thc nitrocyanamide group and the steric problems encountered because of

the presence of the adjacent nitro group; this explanation does not hold

in the case of cyanuric chloride. However, metathetical reactions with

picryl halide and cyanuric chloride have generally not been successful;

for example, numerous attempts to react a metal nitrite with these

compounds to form a C-NO 2 bond have not been successful.

35

In summary, we feel that further work on the reactions of silver

nitrocyanamide with cyanuric chloride or picryl chloride will not be

profitable. However, efforts to incorporate the nitrocyanamide group

into energetic organic molecules should continue. This group has been

largely overlooked by researchers, but its relatively easy synthesis,5,6

favorable heat of formation, and possible contribution to density should

be considered in future synthetic efforts.

Fluorination of Dinitrofuran (DNF)

2,5-Dinitrofuran was prepared by the method of Hill and White8 as

shown in Equation (10).

HN0 3 /0\COOH (10) 0 2 N NO 2

Before using this procedure for the synthesis of 2,5-dinitrofuran,

considerable effort was expended in trying to prepare it by the route

of Nazarova and Novikov9 as shown in Equations (1l)-(14).

oHN03

Br COOi Ac2 BrI NO2 'No

360()

NO,,W

The synthesis of the intermediates, 5-bromo- and 5-iodo-2-nitrofuran,

gave no problems, but numerous attempts to prepare DNF failed. At

best, traces of the DNF were detected by thin layer chromatography, but

the desired product was never isolated. Also, the bromo and iodo

intermediates must be handled with great care to avoid contact with skin.

Even dilute concentrations of 5-bromo-2-nitrofuran cause serious burns.

It is obvious that the preferred route to DNF is through the procedure of

Hill and White; the Russian procedure should be avoided.

Three attempts were made to fluorinate DNF to give the target

compound 3,4-difluoro-2,5-dinitrofuran, as shown in Equation (15).

H H F F

0 N- N F2/N2, HF / \:02 NO2 (15) O2 N 02

These fluorinations were carried out by bubbling a 30% (v/v) mixture of

fluorine in nitrogen through a solution of DNF in anhydrous HF. When the

fluorination was run at ambient temperature (-19 0C) or at 00C, the fluorine

nmr spectrum of the crude semisolid product exhibited many peaks between

60 and 100 ppm upfield from the fluorotrichloromethane reference.

Since the large number of peaks indicated decomposition of DNF, a second

fluorination was run at OC and at a much lower fluorine concentration

(10% v/v) and flow rate. The fluorine nmr spectrum of this product had

only four major peaks (69, 83, 91, and 96 ppm) upfield from fluorotrichloro-

methane. Because these shifts were in the region expected for an aromatic

fluorine compound, a separation of products was attempted. Column

chromatography of the product on silica gel using 50% methylene chloiide

in hexane eluted only the starting material. The column was stripped

with ethyl acetate and the solvent evaporated, leaving a residue that

37

:Ne

exhibited strong carbonyl and hydroxyl absorptions in the ir spectrum,

which indicated that significant decomposition had occurred. Nmr

analyses of these products showed no shifts in the aromatic fluorine

region that were present in the crude reaction product.

The presence of only four major peaks in the fluorine nmr spectrum

indicates that the fluorination was more selective at a lower reaction

temperature and fluorine flow rate. Still more selectivity might be

possible at temperatures less than 00C and with slower addition of A

fluorine. Although it is not confirmed that the desired fluorination

is occurring, the presence of relatively few fluorine peaks in the

correct region of the nmr spectrum is promising. We feel that continued

research on this subject could be productive and suggest fluid-bed

fluorination techniques be studied in addition to the low-temperature,

low-fluorine system described above.

Dipolarophile Additions to Fluorodinitroacetonitrile Oxide (FDNO)

A continued effort was carried out on the reaction of dipolarophiles

with fluorodinitroacetonitrile oxide (FDNO). The objective of this phase

of our research was to react FDNO with an energetic dipolarophile to form

a dense, overoxidized product. This research was based on the work ,

of Adolph'°; the general subject of dipolarophile additions has been

extensively reviewed by Huisgen.1,12

A stock solution of fluorodinitroacetaldoxime, the precursor to FDNO,

was prepared by the oxidation of fluorodinitroethylamine with m-chloroper-

benzoic acid:

Nit3/1 20 m-ClC 6H10C0

31[

CF(NO CI l /12 0 CF_(NO2) 2C__2 N _. CF(NO2 ) 2 C11 (=NOII)2)2C 2 - (16) (17)

38

B j

This stock solution of the oxime in methylene chloride was stored at

-300C to prevent isomerization to fluorodinitroacetamide. FDNO was

generated as needed by treating the oxime with dinitrogen tetroxide, as

in Equation (18).

N204CF(N02)2CH(=NOH) - CF(NO2)2CNO + HNO2

(18)

The reaction of FDNO with fluorodinitroacetonitrile was run with

the objective of obtaining the oxadiazole shown in Equation (19).

FC(N0 9 ),CN + FC(N0 2 ) CNO - -FC (NO )--N\ !I

(N0 2 ) 2 F

13,I

Fluorodinitroacetonitrile was prepared by known procedures,1 3'6 shown

in Equations (20)-(22); it can be stored for extended periods of time

without decomposition.

HNO s HBr Fc-c

NCCH2COOH (N02)3C-CN Na (NO 2C-CN FC(N0 2)2CNoleum NaOHl (22)(20) (21)

One equivalent of fluorodinitroacetonitrile was added to a solution of

the fluorodini troacetaldoxime/NO2 adduct,14 and the resulting solution

was heated to form FDNO in situ, which was expected to react with

fluorodini troacetoitrile to form the oxadiazole. The product was a

pale yellow liquid and was identified as bis(fluorodinitroiethyl) furoxane

39

L

by comparison with an authentic sample prepared by the procedure reported

by Adolph, 10 Equation (23).

2FC(NO,2)CNO (23 FC(NO ) 2C-C-C(NO2) ?F

N N

The reaction was repeated using a tenfold excess of fluorodinitro-

acetonitrile to reduce the probability of self-condensation of FDNO,

which results in formation of the furoxane. However, the only product

obtained from this reaction was the furoxane. Since the electronegative

groups in fluorodinitroacetonitrile should make it very reactive toward

FDNO, the fact that the furoxane was the only product indicates that the Iself-condensation reaction of FDNO is very rapid and the condensation

with fluorodinitroacetonitrile was unlikely.

We continued our work on FDNO condensations by studying its reaction

with nitroethylene. The expected product from this reaction is a

fluorodinitron:troisoxazoline as shown in Equation (24).

FC(N02)2CNO + CH2 = CHN02 FC(N 2) C-_N(24)7

CH2 >'CH

NO2

or

FC(N 2 )-C==N

02NICH \ 0

CH2

The procedure was the same as that used for the attempted additions

of fluorodinitroacetonitrile to FIDNO. The nitroethylene addition yielded

40

a yellow liquid that did not contain any bis(fluorodinitromethyl)

furoxane, based on ir analysis. The ir spectrum had an absorption

corresponding to -C=N-, and the proton nmr spectrum indicated the

presence of several products that contained the -CH2-CH(NO,)- group.

Many attempts were made to separate the products of this reaction

by column chromatography and distillation. In general, these attempts

were unsuccessful and resulted in little or no separation of the com-

ponents. However, one chromatographic separation was partially successful.

In this separation the crude product was passed through a silica gel

column and eluted with varying mixtures of methylene chloride and hexane.

At first, the eluant was 20% methylene chloride in hexane, and the

percentage of methylene chloride was increased incrementally until I00

methylene chloride was eluting and no more of the product mixture came

off the column. The column was then stripped with acetonitrile. All

the fractions collected up to fraction 40 appeared to be varying

mixtures of reaction products, based on ir and nmr spectra. The nmr

spectra of these mixtures very clearly showed the presence of several

compouids that contained the -CHo-CH(NO,)- moiety, and the ir spectra

indicated that ketones and alcohols were present. The rechromatographing

of these fractions not only failed to provide further separation of

components but also led to small changes in some of the components as i

shown by their more complex nmr spectra. However, fractions 41 to 47

gave a pure solid product that melted at 1450C after recrystallization

from ethyl acetate/chloroform. Based on the ir and elemental analyses,

the mass spectrum, and 111 and 1C nmr spectra, we identified this product

as 5,5/ -dinitro-3,3'-bi-2-isoxazoline:

N IN\

0'

NO, NO2

411

The mass spectrum and the 111 and 13C nmr spectra are included in the

experimental portion of this section.

The density of 5,5'-dinitro-3,3'-bi-2-isoxazoline was found to be

1.686 g/cm3 . The estimated density using group additivity techniques

was 1.635, which was 3.02% low. Although there is no doubt concerning

the structure assigned to this molecule, no acceptable mechanism for its

formation has been postulated. Any mechanism must account for the loss

of fluorodinitromethyl groups and the formation of a symmetrical dimer.

No similar products have been reported in previous research on dipolarophile

additions. The mechanism of this reaction would probably be clearer if the

other reaction products could be isolated and identified. Because our

previous experience with the reaction of FDNO with fluorodinitroacetonitrile

indicates that FDNO dimerizes to bis(fluorodinitromethyl)furoxane, as was

shown in Equation (23), we suspected that 5,5'-dinitro-3,3'-bi-2-isoxazoline

may be a product of the reaction of nitroethylene with the furoxane.

Therefore, we prepared a sample of the furoxane and refluxed a solution

of the furoxane and nitroethylene in methylene chloride for 16 hours.

There was no reaction. This indicates that the isoxazoline is a product

of the reaction between FDNO and nitroethyletie; therefore, it inay be

possible to react FDNO with other olefins to yield the desired isoxazoline

product.

Additional research on dipolarophile additions with FDNO were carried

out by studying the reaction of FDNO with 4,4,4-trinitrobutene, as shown

in Equation (25).

42

r

FC(N02 ) 2CNO + (NO2 )3CCH2 CH=CH2 FC(NO2 ) 2= F CC-0N(25) / \

H H

CH

C(N02)3

or

FC (NO) 2 -C--N

(NO 2 ) 3 C-CH 2-Cd 0

012

The 4,4,4-trinitrobutene was prepared by the reaction of allyl bromide

with silver nitroform as shown in Equations (26) and (27).

Ag20 BrCHCH=C"t2HC(N02 )3 (2 6 AgC(NO2 )3 2 7)(26) (27)

(NO2 ) 3CCI12CH=CH 2

The attempted condensation reaction was run as described above with

nitroethylene, and a light-yellow semisolid material was obtained.

The ir and nmr spectra of the crude product indicated that it was a

mixture of several compounds; however, the nmr spectrum contained peaks

corresponding to those expected for the desired product. The presence

of the -CH 2 -CH[C 2C(N0 2 ) 3]- moiety was easily discerned by nmr, and ir

analysis indicated that the -CNO group had reacted but that the

fluorodinitromethyl group was still present. Extensive thin layer

43

chromatography and column chromatography using several solid and liquid

phases gave mixtures of products. Nmr analyses of the products obtained

from liquid chromatography samples show that some separation occurred,

but mixtures were always present. These analyses also show that the

components of these mixtures are similar and that the trinitroethyl-

ethylene group is present in several molecular orientations. Chromatography

of fractions from initial chromatographic separation resulted in a further

separation of products, but a decomposition of products also was evident

by the more complex nmr spectra. No pure products were isolated.

Difficulties encountered in our attempts to isolate a product from this

reaction are similar to those involved in the isolation of a product

from the reaction of nitroethylene with FDNO, in which only 5,5'-dinitro-

3,3 -bi-2-isoxazoline was obtained from a complex mixture. 5,5'-Dinitro-

3,3 -bi-2-isoxazoline was not isolated from the FDNO-trinitrobutene

reaction.

In summary, the addition of energetic dipolarophiles to FDNO appears

to be a complex 3action leading to mixtures of compounds whose separation

is difficult. Additional research in this area could be useful if more

complete separation of reaction products can be effected. Thin layer

and high pressure liquid chromatography are attractive techniques that

should be considered.

44

Oxidation of 3,6-Diaininotetrazine

Research was also conducted on the synthesis of 3,6-dinitrotetrazine

by the oxidation of 3,6-diaminotetrazine. 3,6-Diaminotetrazine was prepared

by the reaction of S-methylthiosemicarbazide hydroiodide with sodium

hydroxide,1 5 as in Equation (28).

/S-CH3 NH,2-N\\ /N-+CH3 NH 2 -. x~ NaOH NH 2 -& C-NH2

HI.NH2 -C C-NH I -HINS2/ pH 8-

NNH, CH3-S (28) H H

J Air oxidationN-N/i \\

NH 2 -C C-NH,,

N=N

A study of the oxidation of 3,6-diaminotetrazine to 3,6-dinitro-

tetrazine was carried out using hydrogen peroxide in trifluoroacetic

anhydride, as shown in Equation (29). Several oxidations were run and

the progress of the reactions followed by hplc.

N -N N-N

S NH2 02 /(CF 3CO) 29) 4 NO22- O,, N /

HN N H2(29) NN

Vigorous oxidation conditions (400C) over a 24-hour period gave

complete oxidation of the diamine to gaseous products. Mild oxidation

'15

conditions (< 100C for 20 minutes) produced one major product based on

hplc analysis. Although the structure is unconfirmed, elemental analysis

and hplc retention time strongly suggest that the product is 3-amino-6-

hydroxylaminotetrazine:

N-NHN NHOH ,

Additional oxidation reactions at ambient temperature for longer times

gave mixtures of products. The progress of the reaction was monitored

by hplc analysis of small samples, which showed the appearance and

disappearance of at least five products. However, none of these products

was predominant except the first product formed, which is presumably

the hydroxylamine discussed above. Elemental analysis of the product

mixture after a reaction period of 3 hours gave an average nolecular jformula of C2HN506 , which is overoxidized when balanced to CO and water.

In addition, these product mixtures are shock sensitive. Very little

work was carried out on isolation of the reaction products, although

we feel that efforts in this area using column chromatography and hplc

would be profitable.

3,5-Bi s(nitrimino)-A s-i, 2,4-triazol ine (NTZ)

A brief study of the azo-bis(nitrimino) group was carried out in

conjunction with our efforts to synthesize NTZ as shown in Figure 1.

The only reference to the synthesis of a compound containing the

azo-bis(nitrimino) group was by G. F. Wright in his synth -s of

azo-bis-nitroformamidine, Equations (30)-(33). 16 fie used 100," nitric

acid in acetic anhydride to convert the chloroimino group to a nitrimino

group. We have prepared this compound on a separate project for Lawrence

Livermore Laboratory (LLL) and have supplied LLL with a small sample

46

..

- z

- z

o to

90

I I~ ) 4 .z Z=" 0 .-

C.)) z .

00

0

z

00

z z

- Z Z~zzl

C I z z

Cl) Z=.) w

z m

-. 0 0C. ) z I

Iz --- 0 z

LdaC) I z IZ uZ=.) ZC.)u

zz

47I

for testing. As an explosive it is balanced to CO and H20; its

measured density is 1.83 g/cm3 .

The density of azo-bis-nitroformamidine was estimated by C. Tarver,

who is now working for LLL. Because the densities of similar compounds

are not available, data on compounds containing the N-C and =N groups

were used, along with the density of nitroguanidine.

Groups Present

NNO2 NNO2 2 [C-N, NH,, =N-NO 2]

H2N-C-N=N-C-NH2 + 2 [N-C, =N]

Azo-bi s-nitroformamidine

Density data on compounds containing the N-C and =N groups gave an

average molecular volume of 8.03 cm3 /mol. To obtain the value for [C-N,

NH2, =N-N0 2], it was assumed that the structure of nitroguanidine was

NHi2C(=N-NO2)NH2 , and the average value for changing -NH2 to -N (bonded

to carbons) was taken from Table 1, Report 4, as -17.23 cm3/mol. By

this method the molar volume for [C-N, NH2, =N-N02] is 49.93 cm3/mol.

Thus, tne molar volume calculated for azo-bis-nitroformamidine is

115.92 cm3 /mol, and the estimated density is 1.76 g/cm3 . The fact that

this value is low by 3.8% could be attributed to the assumptions made

concerning the structure of nitroguanidine. As more derivatives

containing the azo-bis-nitrimino groups are synthesized, the molar

volume of this group can be determined accurately and better density

estimations can be made.

The proposed synthetic route to NTZ, given in Equations (34-36),

employs biguanide as starting material. Biguanide can be chlorinated

to hexachlorobiguanide (1ICB) by treating it with JIOCl in acid solution.

IICB is a shock-sensitive, orange solid that melts at 650C and is stable

for long periods if protected from atmospheric moisture. 11CB can be

48

cyclized to 3,5-bis(chlorimino)-A'-triazoline (CTZ) by treatment with

activated charcoal or by treatment with a base followed by careful

acidification. CTZ is a slightly shock-sensitive, yellow crystalline

solid that melts at 1200C with decomposition. Efforts to convert CTZ

to NTZ by reaction conditions used to convert azo-bis-chloroformamidine

to azo-bis-nitroformamidine have not been successful. Little or no

organic product is recovered from this reaction, indicating that the

triazoline ring decomposes during the nitration. Variation in reaction

temperature and reaction time and the use of HNO3-CF3COOH in place of

HNO,-CH3 COOH should be examined.

We also found that NH2C(=NCI)NHC(=NCI)NH2 , which has not been

reported previously, can be prepared by the reaction of biguanide with

HOCI at p11 5, as shown in Equation (37). Although this compound is of

no interest in the current program, it has potential as an interesting

intermediate for other highly overoxidized explosives.

3,6-Bis(nitrimino)-3,6-dihydro-l,2,4,5-tetrazine

Closely related to NTZ is the nonhydrogen compound 3,6-bis(nitrimino)-

-3,6-dihydro-l,2,4,5-tetrazine, which we attempted to prepare by the

reactions shown in Equations (38)-(40). Because Equation (35) involved

loss of chlorine and coupling to form an azo group and because we have

shown that this is a general reaction for these types of NC1 compounds,

we felt that pentachloroguanidine could be made to couple twice to form

3,6-bis(chlorimino)-3,6-dihydro-1,2,4A,5-tetrazine, as in Equation (39).

This reaction was tried several times and gave only low yields of a

product insoluble in organic solvents. An elemental analysis of this

product indicated an average molecular formula of CNCl , which is

indicative of a polymeric product. It is evident that the linear

coupling reaction is favored over ring formation, even at high dilution,

possibly because of the slight strain in the expected tetrazine ring system.

49 j

A second possible route to 3,6-bis(nitrimino)-3,6-dihydro-l,2,4,5-

tetrazine is shown in Equations (41), (42), and (40). Azo-bisformamidirne

can be converted to azo-bis(N,N,N'-trichloroformamidine) by reaction with

acidic HOCI. Azo-bis(N,N,N'-trichloroformamidine) is an extremely

shock-sensitive compound; it forms red-orange plates from hexane that

melt at 78-80C. Conversion of this compound to a tetrazine, as in

Equation (42), has not yet been attempted.

Oxidation of Guanazole

One attempt was made to oxidize guanazole to the dinitro derivative

shown in Equation (43). ]N-C-N11 2 Lo]N- \\

2 (43) 0N-C N

NNH H

Guanazole (1 g) was slow]' added to a mixture of trifluoroacetic

anhydride (12.6 ml), 90% hydrogen peroxide (2 m3), and chloroform (18.4 ml)

at 5 0 C. The solution turned from blue-green to yellow over a 90-minute

period. Aliquots were taken at 30 and 90 minutes, and the remainder of

the material was left to react overnight. After workup, several spots

were observed on a silica gel tlc of the crude product. The crude product

mixture was run through a silica-gel column with anhydrous acetone.

The first cut, a liquid, shows C=O and C-F absorption in the ir, and a

sharp singlet at 2.19 ppm and a broad peak at 5.45 ppm in the nmr

(Inte',ration 3 to 1) . This cut appears to contain some trifluoro-

acetic acid. The remaining three cuts are yellow solids. Their ir

spectra show little or no C-O or C-F absorption; however, no C-NO 2

50

absorption is present either. The nmr spectra show a number ofscattered peaks, indicating a mixture of several compounds. None of

the materials is sensitive to a sharp hammer blow.

51

"I

Experimental Details

The following experiments are given in detail because they

describe the synthesis of either new compounds or key intermediates.

The general descriptions of other reactions studied during this program

are given in the preceding discussion. Elemental analyses were performed

by Georgina Hum on a Perkin-Elmer Autosampler, infrared spectra were run

on a Perkin-Elmer 247 Spectrometer, 1H nmr spectra were run on a Varian

EM-360 spectrometer, and 13C and 19F nmr were run on a Varian XL-100

spectrometer.

3,5-bis(chlorimino)- '-1,2,4-Triazoline

To a solution of 0.75 mol (30 g) sodium hydroxide in 30 ml water

cooled to 50C was added, portionwise over 30 minutes with vigorous

stirring, 0.025 mol (7.6 g) hexachlorobiguanide. The deep-orange-colored

solution obtained was stirred for another hour at room temperature

and then cooled in an ice/salt bath. Concentrated HC1 was then added

carefully, and a violent evolution of chlorine was observed at pH 6.0,

yielding a bright-yellow solution. This solution was extracted six times

with 50-ml portions of chloroform, and the combined chloroform solutions

dried over MgSO4 and concentrated on the rotary evaporator at 250C. The

resulting yellow solid was recrystallized from chloroform/hexane, forming

pale-yellow needles. Yield 1.1 g (27%). Mp 1200C (dec). Elemental

analysis calculated for C2HNC12 : C, 14.46; H, 0.60; N, 42.17. Found:

C, 14.97; H, 0.57; N, 42.69. IR (CHC13 ): 2.94 pim (in, N-H), 6.04 pim

(w, N=N), 6.18 pim (s, C=N), 6.23 pim (w, C-N), and 8.58 pim (s, N-Cl-).

3-Amino-6-hydroxylamino-s-tetrazine

To 18.4 ml chloroform at OC was added 12.6 ml trifluoroacetic

anhydride over a 15-minute period at 0-5°C. To this mixture was added

2 ml (82 mmol) 90% hydrogen peroxide at 0-50C with very vigorous

52

stirring over 20 min. Diaminotetrazine, 1 g (8.9 mmol), was added

in small porti.ns to the mixture at 0-50C over 15 min. The reaction

mixture was stirred at 0-100C for an additional 20 min and then

evaporated to dryness. The residue was extracted with warm acetone,

filtered, and dried. Elemental analysis calculated for C2H4N 0:

C, 18.75; H, 3.15; N, 65.60. Found: C, 19.59; H, 3.02; N, 64.76.

Hexachlorobiguanide

To 200 ml 5.2% NaOCl (0.20 mol) over 40 ml CFCI3 was added a

solution of 2.00 g biguanide (0.02 mol) and 16.4 ml 37% HCI (0.20

mol) in 50 ml water. The biguanide solution was added over a period

of 20 min. A slight temperature rise was noted, and additional CFC1 3

was added to replenish the CFCl3 as it boiled off. After addition of

the biguanide, the reaction was stirred for about 15 min or until

the aqueous phase was nearly transparent. The CFC13 phase was separated,

dried (Na2 SO4 ), and the solvent removed under vacuum to give 6.22 g of

a yellow viscous liquid. This material was dissolved in a minimum amount4!

of CFC13 (- 30 ml) and placed in a -180C freezer for several days. The

yellow crystalline solid that formed was collected. Yield 2.61 g. Mp

690C. This compound is very shock sensitive and can be detonated with

a light hammer blow. It was identified as hexachlorobiguanide by its

elemental analysis. Elemental analysis calculated for C2HN5C16 :

C, 7.81; H, 0.34; N, 22.77; Cl, 69.08. Found: C, 8.38; H, 0.34;

N, 22.53; Cl, 68.71.

5,5'-Dinitro-3,3'-bi-2-isoxazoline

A solution of 8.11 g (95 mmol) 2-fluoro-2,2-dinitroacetaldoximel0

in 150 ml methylene chloride was cooled to OC, and nitric oxide was

bubbled in slowly at 0-50C until a total of 11 g had been added.

The reaction mixture was then allowed to stand at 5oC for 15 hr.

53

Nitroethylene, 30.5 g (486 mmol), was added to the reaction mixture, and

the mixture was refluxed for 16 hr until the evolution of oxides of

nitrogen had ceased. The solvent was then evaporated, and the residue

was passed through a silica gel column. Initially the eluant was 20%

methylene chloride in hexane, but this was increased incrementally until

100% methylene chloride was being used. The fractions eluted with

100% methylene chloride were combined and evaporated to a solid residue,

which was recrystallized from ethyl acetate and chloroform, giving white

needles that melted with decomposition at 1450C. Yield 2.6 g.

Elemental analysis calculated for C6 H6 N406 : C, 31.31; H, 2.63; N, 24.35.

Found: C, 31.60; 2.58; N, 24.80. Pmr (CD3 CN); 3.90 (-CH2-, doublet,

area 2), 6.35 6 (-CH-NO2 , triplet, area 1) (see Figure 2). Cmr (CD3CN)

off resonance, referenced to TMS; 42 (CH2, triplet), 106 (-CH-N02,

doublet), 152 ppm (C=N, singlet) (see Figure 3). The mass spectrum is

shown in Figure 4.

Hexachloroazobisformamidine

To 170 ml 5.25% NaOCl (120 mmol) over 40 ml methylene chloride

was added a solution of 1.20 g azobisformamidine dinitrate 17 ,'8 (5 mmol)

and 11.8 g 37% HCl (120 mmol) in 25 ml water. During the addition,

which took 12 min, the mixture was stirred slowly and the temperature

was kept at 25-20°C with a cold water bath. After the addition the

mixture was stirred until the aqueous phase became nearly clear. The

methylene chloride phase was separated, dried (MgS04 ), and the solvent

removed, leaving 0.32 g of a dark-orange liquid that crystallized after

sitting for 16 hr at 50C. This material was recrystallized from hexane/

dichloroethylene to give a crystallii c product that melted at 74-76°C (dec.).

This product was very sensitive and could be detonated with a light

hammer blow. It was identified as hexachloroazobisformamidine by its

infrared spectrum.

54

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REFERENCES FOR SECTION II

1. R. Hesse and D. Barton, Chem. and Eng. News, April 26, 1976, p. 23.

2. R. J. de Pasquale, J. Org. Chem., 38, 3025 (1973).

3. C. E. Inman et al., J. Amer. Chem. Soc., 80, 6533 (1950).

4. A. F. McKay, Can. J. Res., 28B, 683 (1950).

5. J. A. Garrison and R. M. Herbst, J. Org. Chem., 22, 278 (1950).

6. C. L. Coon, unpublished results.

7. S. R. Harris, J.A.C.S., 80, 2302 (1958).

8. R. Hill and A. White, Am. Chem. Jour., 27, 193 (1902).

9. Z. N. Nazarova and V. N. Novikov, Zh. Obshch. Khim., 31, 263-267 (1961).

10. H. G. Adolph, J. Org. Chem., 40, 2626 (1975).

11. R. Huisgen, Angew. Chem. Internat. Edit., 2, 565 (1963).

12. R. Huisgen, Angew. Chem. Internat. Edit., 2, 633 (1963).

13. C. 0. Parker, W. D. Emmons, H. A. Rowewicz, and K. S. McCallum,Tetrahedron, 17, 79 (1962).

14. J. Hine and W. S. Li, J. Org. Chem., 40, 1795 (1975).

15. C. Lin, E. Lin, E. Lieber, and J. P. Horwitz, J. Am. Chem. Soc., 76

427 (1954).

16. G. F. Wright, Can. J. Chem., 30, 62 (1952).

17. Thiele, Annalen, 270, 39 (1892).

18. A. Kreutzberger, J. Am. Chem. Soc., 81, 6017 (1959).

58

DISTRIBUTION LIST

Copies

Draft for

Approval Approved

Contracting Officer

Naval Surface Weapons Center


Silver Spring, MD 20910

Attention: NSWC/WR-1I 1 3

NSWC/WR-1O 1 1

NSWC/WS-Il 1 1

NSWC/WX-21 3

Defense Advanced Research Projects Agency 1

1400 Wilson Boulevard

Arlington, VA 22209

Attention: Dr. Ernest F. Blase

Commanding Officer 1

DCASMA, San Francisco

866 Malcolm Road

Burlingame, CA 94010

Mrs. Marjorie Pellman

for Dr. M. J. Kamlet

Department of Chemistry

University of California at Irvine

Irvine, CA 92664

59

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REPORT DOCUMENTATION. PAGE BEFORE COMPLETING FORM1. REPORT NUMBER 2. GOVT ACCESSION NO. 3. RECIPIENT'S CATALOG NUMBER

4. TITLE (and Subtitle) 5. TYPE OF REPORT & PERIOD COVERED

Density Estimation fol- New Solid and Liquid Final Report

Explosives 17 May 1976 through

16 February 19776. PERFORMING ORG. REPORT NUMBER

7. AUTHOR(s) SRI Project PYU-5425"8. CONTRACT OR GRANT NUMBER(s)

C. M. Tarver, C. L. Coon and J. M. Guimont N60921-76-C-0146 '1

9. PERFORMING ORGANIZATION NAME AND ADDRESS 10. PROGRAM ELEMENT, PROJECT, TASK

Stanford Research Institute I AREA & WORK UNIT NUMBERS

333 Ravenswood Avenue

Menlo Park, CA 94025 12. REPORT DATE 13. NO. OF PAGES11. CONTROLLING OFFICE NAME AND ADDRESS 17 February 197 61Naval Surface Weapons Center, WOL

White Oak, Silver Spring, MD 20910 15. SECURITY CLASS. (of this report)

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15a. DECLASSIFICATION/DOWNGRADINGSCHEDULE

16. DISTRIBUTION STATEMENT (of this report)

Approved for public release; distribution unlimited.

17. DISTRIBUTION STATEMENT (of the abstract entered in Block 20, if different from report)

18. SUPPLEMENTARY NOTES

19. KEY WORDS (Continue on reverse side if necessary end identify by block number)

density nitrocyanamides

explosives nonhydrogen explosives

fluorodinitromethyl nitriminesnitramines chloro-nitro compounds

20. ABSTRACT (Continue on reverse side if necessary and identify by block number)

' The group additivity approach was shown to be applicable to density estima-

tion. The densities of approximately 180 explosives and related compounds ofvery diverse compositions were estimated, and almost all the estimates were quitereasonable. Of the 168 compounds for which direct comparisons could be made (see

Table 6), 36.9% of the estimated densities were within 1% of the measured

densities, 33.3% were within 1-2%, 11.9% were within 2-3%, 8.9% were within 3-4%, -

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19. KEY WORDS (Continued)

20 ABSTRACT (Continued)

and 9.0% were more than 4% different from the measured densities. Thus, of the

densities estimated in this study, 82% were within 3% of the measured density.The average absolute error in density was approximately 0.022 g/Cm 3, and the

absolute error in density exceeded 0.04 g/cm 3 for only 24 of the 168 compounds(14.3%). The largest errors occurred for compounds with several bulky, highly

polar groups in close proximity, and for compounds containing groups whose

calculated molar volumes were based on density data for only two or three

compounds. As more density data for a certain group configuration become

available, the molar volume can be determined more accurately, and the overall

agreement between measured and estimated densities of compounds containing that

group should improve.

Synthetic work was carried out on a number of newly postulated explosives

or explosives whose syntheses were expected to be difficult. Progress was made

toward the synthesis of 3,6-bis(nitrimino)-3,6-dihydro-1,2,4,5-tetrazine and

3,5-bis(nitrimino)-A /-i,2,4-triazoline, which contain no hydrogen and are highly

energetic. Syntheses were developed for the preparation of the important

intermediates hexachloroazobisformamidine and 3,5-bis(chlorimino)-A'-1,2,4-

triazoline. In addition, the oxidation of diaminotetrazine was partiallysuccessful in that the partially oxidized intermediate, 3-amino-6-

hydroxylamino-s-tetrazine, was isolated.

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