Saturday, December 16, 2017

wlcome ! making a highly impact insensi- tive form of HMX called Alpha HMX - having an average particle size of 5 microns "HMX, which is known as l,3,5,7-tetranitro-l,3,5,7- tetraazacyclooctane, is the most powerful non-atomic 25 explosive in military use...The special insensitivity of this HMX is due to several factors, each of which must be held in tight tolerance. The particle size must be kept to about 1 to about 5 micron in range, the polymorph must be alpha, and the purity must be very high. To obtain the right poly- morph the amount of nitric acid used must be carefully controlled as too high or too low a dilution could cause the formation of gamma HMX..."

SUMMARY OF INVENTION 

65 

It is an object of this invention to provide an im- 
proved process of making HMX which provides both 
high power, and extreme insensitivity, at a price which 



The special insensitivity of this HMX is due to several 
factors, each of which must be held in tight tolerance. 
The particle size must be kept to about 1 to about 5 
micron in range, the polymorph must be alpha, and the 
purity must be very high. To obtain the right poly- 
morph the amount of nitric acid used must be carefully 
controlled as too high or too low a dilution could cause 
the formation of gamma HMX. Further, the tempera- 
ture of the reaction must be kept as close to room tem- 
perature as possible because if the temperature rises 
above 45 degrees Centigrade, the product again ob- 
tained is gamma HMX, instead of alpha HMX, the de- 
sired product. To obtain the right size, the product must 
be precipitated with great agitation in the manner de- 
scribed with a high speed mixing turbine at about 15,000 
RPM. The purity of the product must be upgraded 
using the solid phase up-grading techniques hereinafter 
described. Failure to follow any and all of the steps in 
the procedure, may seriously compromise, if not pre- 
vent the establishment of the special property of insensi- 
tivity to this alpha HMX material. 

EXAMPLE 1 

Nitration of TAT with a mixture of nitric acid and 
phosphorous pentoxide. 

250 grams, within the effective range of 200 to 300 
grams, of 98% nitric acid were introduced into a 500 ml. 
beaker, provided with a thermometer, and a magnetic 
stirring bar. 70 grams of phosphorous pentoxide were 
then added in portions over a 30 minute period. The 
addition was made with stirring via the magnetic stir- 
ring bar and the rate of addition of the phosphorous 
pentoxide was dictated by the temperature of the reac- 
tion mixture, which was not permitted to rise above 35 
degrees Centigrade. The reaction mixture was allowed 
to stir covered by a piece of aluminum foil until the 
temperature fell to room temperature. 50 grams of TAT 
were then added in about 4 equal portions at such a rate 
that the temperature was prevented from rising above 
40 degrees Centigrade. The reaction mixture was al- 
lowed to fall to room temperature, and the stirring bar 
was removed when all signs of any exothermic action 
had subsided. The beaker was covered by aluminum foil 
and allowed to set undisturbed for 16 hours at room 
temperature. During this time the entire reaction mix- 
ture sets-up to a cream cheese like consistency. 

The reaction mixture is discharged directly into the 
vortex of a room temperature water bath stirred by an 
L-TEC air turbine mixed, (see U.S. Pat. No. 4,424,677), 
specifically designed for very high speed mixing and 





dispersing. The water acts to brake the reaction com- 



4 



plex, and precipitates the alpha HMX, guaranteeing the 
formation of extremely small particles (crystals). The 
solid crude alpha is filtered, and washed with as much 
cold water as necessary to reach a constant of 7 ph. 
(This water should be maintained between 10 to 35 
degrees Centigrade to prevent any digestion of the size 
of the crystals. The filtered but damp cake is then dis- 
persed in 6 to 8 times its mass of agitated boiling water. 
The total washing time should not exceed 2 minutes in 
order to prevent size enhancement via digestion. The 
washed crude HMX, which should have no odor, is 



METHOD B 

The quantities and methods as in Example 1 above, 
however, a water proof container is employed and the 
mixture is placed in a constant temperature bath at 40 
degrees centigrade. The thickness of the paste in the 
container is limited so as to permit attainment of bath 
temperature throughout the mixture in a reasonable 
period of time. If necessary the mixture may be stirred 
mechanically. Under these conditions the upgrading 
time is reduced to approximately 4 hours. 



then filtered hot, and rinsed with cold water. This cur- 



METHOD C 



tails crystal digestion before being thoroughly dried. 
The drying may be simple air drying, or vacuum drying 
at a temperature near 50 degrees Centigrade. 

The still crude HMX must now be up-graded in pu- 
rity before use. This is accomplished by anyone of the 
following methods. 

PART 2 



The same quantities were used as set forth in Example 
1 however, the mixture is fed through a heated screw 
mixer or feeder for rapid mixing and temperature equili- 
bration. The temperature may be adjusted upwards to 
the 70 degree region reducing the reaction time to a 
matter of minutes. 

RESULTS 



METHOD A 

Purification of the contaminated HMX produced above 
by trituration with a nitric acid/phosphorous pentoxide 
mixture. 

100 grams of the contaminated HMX are added por- 
tion wise to 100 grams of nitric acid (about 70 ml.), 
within the effective range 80 to 120 grams, containing 
12.5 grams, which is within effective range 10 to 14 30 
grams, of phosphorous pentoxide. The container may 
be a simple beaker which may be covered with alumi- 
num foil. The quantity of nitric acid used here may be 
increased (not above 1 30 grams) for easier mixing of the 
mixture. The quantity used here has been found to be 35 
given about as thick a mixture as is practical. The quan- 
tity of phosphorous pentoxide may be reduced or in- 
creased depending for the greater part upon the amount 
of water originally present in the nitric acid and the 
amount of SEX present in the sample. The quantities 40 
used here have been found to work well over a very 
wide range of sample purities with initial melting points 
as low as 230 degrees centigrade. The phosphorous 
pentoxide should be fully dissolved and contain no solid 
particles. The nitric acid may be prepared ahead of time 45 
and kept as a stock solution. The HMX must be free of 
DANNO (l,5-diacetyloctahydro-3-nitro-7-nitroso- 
1,3,5,7-tetraazocine), since contamination with this 



The impact values obtained via the “ERL, Type 12 
Impact Tester” using a 2 and one half kilogram mass, 
demonstrated values 5 to 10 times greater than normally 
achievable with “Class 5 Beta HMX”, and kinetic en- 
ergy values 10 to 20 times greater than normal, As the 
following actual data indicates 



DROP 


Initiation y = yes, n = no 


100 cm drop 


n 


100 cm drop 


n 


100 cm drop 


n 


100 cm drop 


n 


100 cm drop 


n 


100 cm drop 


n 


100 cm drop 


n 


100 cm drop 


n 


100 cm drop 


n 


100 cm drop 


n 


150 cm drop 


n 


150 cm drop 


n 


150 cm drop 


y 


150 cm drop 


n 


150 cm drop 


n 


150 cm drop 


y 


150 cm drop 


n 


150 cm drop 


y 


150 cm drop 


n 


1 50 cm drop 


y 



compound can cause dangerous fume-offs. The gradual 

addition of the HMX to the nitric acid solution is to 50 Do t0 tbe dam age being caused to the test apparatus 
facilitate the mixing as no exothermic action should by the lar 8 e amount of kinetic energy released from 

occur. The paste is left for about 16 hours at room tern- sucb S reat dro P heights it was decided to accept the 

perature, samples may be taken to determine comple- 50% initiation value as being somewhere above 150 cm. 

tion of the reaction. Reactions have been intentionally ANAT Y

Cielo e terra (duet with Dante Thomas)