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Warning.
There may be certain federal, state or local laws which prohibit the possesion
or manufacture of certain substances mentioned herein. Severe penalities may
be prescribed for violation of such laws. Be warned!
The procedures to be followed in this manual and the resulting end-product
are extremly dangerous. Whenever dealing with high explosives, special
precautions should be followed in accordance with industry standards for
experimentation and production of high explosives. Failure to strictly such
industry standards may result in harm to life or limb.
Therefore, the author disclaim any liability from any damages or injuries of
any type that a reader or user of information contained within this manual may
encounter from the use of said information. Use this manual and any end-
product or by-product at your own risk.
Preface.
The information in this manual serves as an introduction to the organic
explosive PETN, pentaerythritol tetranitrate. Included are important physical
and chemical properties with which the reader should be familiar before
proceeding to the section that describes in detail one of several proven
methods for the manufacture of high-grade PETN. Finally it should be
mentioned that the chemicals listed in this text are hazardous if used im-
properly or handled carelessly. The reader is urged to adopt a "think before
you do" attitude, pay attention to details, and use safe laboratory equipment
and procedures.
1. PETN: Its Discovery and Properties.
The high explosive pentaerythritol tetranitrate was first synthesized in
1894 at the Rheinish-Westfalische Sprengstoff Company in Germany by a chemist
researching the nitration process of pentaerythritol in a high concentration
of nitric acid. The resulting explosive was collected, tested, and found to
have a very fast rate of detonation, high density, and good chemical stability,
making it an ideal substance for military use. Unfortunately, at that time
there was no means available to mass-produce the raw ingredient pentaery-
thritol. PETN thus remained a laboratory interest until World War II, when it
was used in ammunition, bombs, and other fragmention devices. During this time,
Germany produced as much as 1,440 tons of PETN per month, with the USA and the
USSR following suit.
Still manufactured on a large scale, PETN remains one of the most powerful
conventional explosives ever developed, rivaled only by HMX and RDX. The
military, as might be expected, is the largest user of PETN, with annual
purchasing well over 2,000 tons. Nonmilitary use is primarily limited to
demolition work and as a booster material for secondary explosives such as
ANFO, dynamite, etc.
Physical and Chemical Properties.
PETN is a white crystalline substance that feels powdery to the touch. In
its pure form, PETN melts at 141.3 degrees centigrade. The boiling point is:
160řC at 2mm Hg
180řC at 50mm Hg
200řC at 760mm Hg (standard atmosphere)
The molecular structure is:
O NOCH H CONO
2 2 2
\ /
\ /
C C H O N
/ \ 5 8 12 4
/ \
O NOCH H CONO
2 2 2 2
The calculated nitrogen content is as follows:
Element # Atoms
x Atomic Wt.
Carbon 5 x 12.011 = 60.055
Hydrogen 8 x 1.00794 = 8.064
Oxygen 12 x 15.9994 = 191.993
Nitrogen 4 x 14.0067 = 56.027
ÄÄÄÄÄÄÄ
Total 316.139
56.027
ÄÄÄÄÄÄÄ
316.139 (100) = 17.722% Nitrogen
Correspond with the military specification MIL-P-387 for PETN:
Melting Point 140.0řC
Nitrogen Content 17.5% Minimum
Substances Insoluble
in Acetone .10% Maximum
Acid or Alkali Content .003% Maximum
Vacuum Stability at 120řC 5ml of gas / 20 hours
Overall Purity 98.7%
If we examine the ultraviolet absorption spectrum of a single PETN crystal,
we find a narrow band in the 280ćm area. Because ordinary sunlight emits UV in
the same range, PETN should not be exposed to the sun for a long period of
time as damage in the form of cracks in the crystals will appear and render
the PETN useless.
2. PETN Manufacture.
PETN can be made in a number of different ways, but the overall process is
always the same and consists of the following steps:
1. Nitration. Adding pentaerythritol to a given amount of nitric acid for
a specific time at a specific temperature to form crude PETN.
2. Washing. The crude PETN is rinsed with distilled water until free of acid,
filtered, and throughly dried.
3. Recrystallization. The dry PETN is dissolved in heated acetone, purified
with a neutralizing agent, and then poured into cold water where the purified
PETN is precipitated.
4. Washing. The pure PETN is again rinsed with distilled water to remove
remaining traces of acid and acetone, filtered, and dried to a 10 percent
water content. The PETN is now ready for use.
We will now proceed to the actual method for making high-grade PETN on a
laboratory scale (larger amounts can be made by increasing the size of the
equipment) that will yield about 500ml per batch. The amount of chemicals used
can vary if one wishes to produce more or less PETN per batch. However, the
proportions and the temperatures are exact and must not be changed under any
circumstances. We will begin with a list of equipment and chemicals needed.
Then each of the steps mentioned above will be detailed and fully discussed.
Hardware Required
1. Stirring hotplate, with at least a 10" x 10" surface area. This type of
hotplate will heat solutions and stir them by spinning a glass-coated bar
magnet that is dropped into the solution being treated. The temperature
and mixing rate are both adjustable by turning two dials on the face of
the machine. The magnetic stir bar should be about 2.75 inches long and
glass coated. If a regular hotplate of the nonstirring type is used, then
all stirring must be done by hand with a glass rod.
2. Glass coated magnetic stir bar 2.75" long
3. One 4,000ml Pyrex beaker of standard configuration, with graduation
4. One 1,000ml Pyrex beaker, tall form with graduation
5. One thermometer graduated in degrees centigrade
6. One thermometer clip to hold thermometer to the beaker
7. A few glass stirring rods
8. Pack of fine-grade filter paper (grade: 230, 33cm diameter)
9. Glass funnel
10. Plastic bucket: one or two
11. Wood or plastic cookspoon (used to scoop PETN crystals)
12. Several pans for drying (disposable pizza pans work well)
13. One graduated cylinder used for measurement. A 100 or 200ml cylinder will
do.
14. Several paper cups
15. Full face shield to protect eyes and face while working with acid.
16. Plastic or rubber gloves
Chemicals Required
The amount of chemicals listed is just enough to make one 500ml lot of PETN.
The reader will have to decide how much to purchase if he decides to vary the
amount of PETN produced.
1. 600ml nitric acid with a purity of 98 percent. (Don't use 70 percent or
90 percentÄuse only 98 percent.)
2. 250ml pentaerythritol, reagent grade
3. 1,500ml acetone, reagent grade
4. One teaspoon sodium carbonate powder, reagent grade
5. 800ml distilled water
6. 30 to 40 gallons of tap water for rinsing. Should tap water be hard or
contain chlorine, distilled water must be used.
7. One vial of red litmus paper, used to test pH level alkaline range 7 to 14
8. One vial of blue litmus paper, used to test pH level in acid range 0 to 7
9. Small bag of crushed ice
10. Optional: Full range 0 to 14 pH indicator strips. These are helpful in
determining the pH of a solution, but litmus will suffice.
All of the hardware and chemicals listed are readily available from major
scientific supply companies. Consult the yellow pages and don't be afraid to
shop around for the best prices.
Procedure
Step One: Nitration
(a) Take the 100ml tall form beaker and fill it with 600ml of nitric acid. Be
sure to wear your face shield when working with acid.
(b) Place the tall form beaker with the acid inside of the larger 4000ml
beaker and center it.
(c) Fill the larger beaker with crushed ice up to the same level as the acid
in the tall form beaker. Now pour tap water over the ice until the level
reaches the 700ml mark on the tall form beaker. Do not let any ice or
water fall into the acid.
(d) Carefully place the stir bar into the beaker of acid.
(e) Using the thermometer clip, attach the thermometer to the rim of the tall
form beaker and adjust it so that the bulb (the part with the mercury)
falls just slightly below the surface of the acid. Be sure the numbers can
be clearly read.
(f) With two hands, carefully lift the whole assembly and place it on the
stirring hotplate and move it around so that the stir bar is centered in-
side the tall form beaker. All controls on the hotplate should be in the
off position.
(g) Using the graduated cylinder, measure out 250ml of pentaerythritol and
pour this into the paper cups (you will most likely need two paper cups).
During the manufacture process, acetone is used to purify crude PETN and to
safely remove crystals that may have condensed on various pieces of laboratory
equipment. Because acetone readily dissolves PETN, a table of solubility is
given below as a reference.
ÚÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÂÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄż
łAmount of PETN ł Acetone Soluble in Water ł
łdissolved in ĂÄÄÄÄÄÄÄÄÄÄÄÂÄÄÄÄÄÄÄÂÄÄÄÄÄÄÄÂÄÄÄÄÄÄÄÂÄÄÄÄÄÄÄ´
ł100 grams of ł 55% ł 70% ł 80% ł 90% ł 92% ł
łsolution (grams)ĂÄÄÄÄÄÄÄÄÄÄÄÁÄÄÄÄÄÄÄÁÄÄÄÄÄÄÄÁÄÄÄÄÄÄÄÁÄÄÄÄÄÄÄ´
ł ł Temperature of Solution in řC ł
ĂÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄĹÄÄÄÄÄÄÄÄÄÄÄÂÄÄÄÄÄÄÄÂÄÄÄÄÄÄÄÂÄÄÄÄÄÄÄÂÄÄÄÄÄÄÄ´
ł 5 ł 1 gr @41C ł 41.5 ł 22 ł ł ł
ł 10 ł 4 gr @62 ł 54.5 ł 38.5 ł 15 ł 10 ł
ł 15 ł ł 62 ł 48 ł 24.5 ł 20.5 ł
ł 20 ł ł ł 54 ł 34.5 ł 29 ł
ł 25 ł ł ł 59 ł 41.5 ł 34 ł
ł 30 ł ł ł 63 ł 46.5 ł 40.5 ł
ł 35 ł ł ł ł 51.5 ł 45 ł
ł 40 ł ł ł ł 55 ł 50 ł
ł 45 ł ł ł ł 58.5 ł 54 ł
ł 50 ł ł ł ł 61.5 ł 57.5 ł
ł 55 ł ł ł ł ł 60.5 ł
ł 60 ł ł ł ł ł 62.5 ł
ŔÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÁÄÄÄÄÄÄÄÄÄÄÄÁÄÄÄÄÄÄÄÁÄÄÄÄÄÄÄÁÄÄÄÄÄÄÄÁÄÄÄÄÄÄÄŮ
The above table indicates a low solubility of PETN in water and this helps
to explain the low toxicity of PETN on the human body. Handling or inhaling
the dust in small amounts causes almost no effect. From a toxic point of view,
PETN, unlike nitroglycerine, TNT, or dynamite, is safe to work with.
Explosive Properties
Pure PETN, when heated above its melting point, explodes at 205-225řC.
A Table of Gaseous Products Released
During Decomposition of PETN
Initiation NO NO N O N CO CO H O
2 2 2 2
Detonation Ä 5.3 Ä 22.8 37.0 26.7 6.8 1.4
Impact Ä 24.3 5.3 9.4 19.1 35.4 6.5 Ä
Thermal 210řC 12.0 47.6 9.5 1.6 6.3 21.0 2.0 Ä
Heat of Explosion: 1,530 Kcal/Kg.
Volume of Gases: 768 L/Kg.
Temperature: 4,230řC
The rate of detonation of a single crystal of PETN, the density of which is
1.77g/cubic centimeter, is 8,500 meters/second. In order to get a cartridge
filled with PETN powder to detonate at the same rate, two things must be done:
1. Pure, dry PETN must be mixed by weight with 10 percent water. This will
drive the air out and allow the detonation wave to travel rapidly from one
crystal to the next. The water also makes the PETN safer to work with, as dry
PETN explodes when subjected to a slight impact.
2. The PETN must be loaded into the cartridge under high pressure so that
the density of the powder approaches the crystal density.
The ideal loading density of a cartridge containing PETN should be in the
range of 1.72 to 1.73g/cubic centimeter. At this density, the 8,500 meter/
second detonation rate can be achieved and the maximum explosive power of PETN
obtained. It should be mentioned, however, that even if a cartridge is only
packed by hand, a very powerful explosive device will still result.
The loading density of a cylindrical cartridge can be determined by using
the following equations:
Force
Pressure = ÄÄÄÄÄÄÄ
Area
Volume = Area x Length
Mass (amount of PETN)
Loading Density = ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ
Volume of Cartridge
We are now ready to continue. Be sure the work area has good ventilation,
and wear your face shield to avoid acid burns in case any beakers are
accidently knocked over.
(h) Turn on the stirrer and adjust until a smooth rapid motion occurs in the
acid. The heater will be in the "off" position during the whole nitration
process. If you are not using a stir bar, the stirring must be
continuously done by hand with a glass rod.
(i) Look at the thermometer. When the temperature falls to 10řC, very slowly
sprinkle in some of the pentaerythritol by squeezing the rim of the cup
to form a spout and shake lightly. As soon as the temperature starts to
rise, stop adding. Look to see where the temperature stops. If it is below
20řC, then continue adding the pentaerythritol and stopping whenever the
thermometer reads 20řC. Allow the whole mixture to cool back to 10řC and
then start sprinkling in the pentaerythritol until 20řC is again obtained.
Continue adding in this manner until all 250ml of pentaerythritol has been
added. When the temperature again falls to 10řC, remove the thermometer
and the stir bar. Take the small beaker out of the larger one and set it
aside for forty-five minutes. The stir switch can be turned off and the
ice-water mixture thrown out.
Important: Never let the temperature of the mixture rise above 25řC during
this operation.
This concludes Step One.
Step Two: First Washing
(a) After forty-five minutes have elapsed, the crude PETN will have settled to
the bottom of the beaker, as a thick yellow-white sludge, with a layer of
acid on top. Pick up the beaker and slowly pour off the top layer of acid,
being careful not to disturb the PETN sludge. When finished, set the
beaker aside and dispose of the waste acid.
(b) Fill a plastic bucket with two gallons of water. Use distilled water if
your tap water is hard or chemically treated.
(c) Pour the beaker of PETN into the bucket and scoop out any sludge with a
wood cookspoon. Using a glass rod, stir the contents of the bucket
vigorously for ten seconds and then wait for the PETN to settle. If a foam
has developed on the surface of the water, be sure to agitate the surface
with your stirring rod. The foam, which is just air trapped in PETN, will
settle to the bottom of the bucket.
(d) After the contents have settled, take a strip of blue litmus paper and dip
it into the bucket. You will notice that the litmus paper turns red,
indicating the presence of any acid. This acid must be removed, so take
the bucket and slowly pour off the layer of water. Be careful not to pour
off any PETN by accident.
(e) Take two gallons of fresh water and pour it into the bucket. As before,
stir to break up the foam and then allow the contents so settle again.
Using a new blue litmus paper, test for the presence of any acid. Should
acid be present, continue the cycle of pouring off the water adding fresh
water, stirring, settling, and testing with litmus paper.
(f) After several wash cycles, you will find that the litmus paper no longer
turns red but instead remains blue, indicating that the rinse water is now
neutral. Wash the PETN one more time, let settle, and pour off the water.
(g) Place a filter paper into the glass funnel. Scoop the PETN from the bottom
of the bucket and put it into the filter. The filter paper and funnel
serve to allow the water to drip away, thus allowing the PETN to dry fas-
ter. Allow the PETN to filter for at least thirty minutes.
(h) After filtering, take the PETN and spread it out as a thin layer in the
drying pans. The PETN must be allowed to dry completely. When dry, it will
be a white crystalline powder. The drying might take several days.
(i) Clean and dry the beakers, stir bar, and thermometer, as they will be used
again during the next step.
(j) After the PETN has dried, place it in any handy containerÄother than the
beakersÄand set it aside.
This concludes Step Two.
Step Three: Recrystallization
(a) Take one teaspoon of sodium carbonate and place it in the tall form beaker.
Add 800ml of distilled water and stir until completely dissolved. This,
your neutralizing solution, will be used shortly.
(b) Fill the 4,000ml beaker with 1,500ml of acetone. Put in the stir bar and
thermometer and place on top of the hotplate. Turn the stir dial to a
medium speed and turn on the heat. The temperature of the acetone will
rise and must be held between 50řC and 60řC. Do not let the temperature
stray out of this range during the next steps. Aim for a temperature of
55řC. Heated acetone is highly flammableÄuse caution!
(c) Take two heaping tablespoons of dry PETN, add it to the acetone, and let
it dissolve completely. The temperature will now drop slightly, but if it
is still above 50řC, take two more tablespoons of PETN, add it to the
acetone, and let it dissolve. Keep up this method of adding two tablespoons
of PETN and letting it dissolve until the temperature reaches 50řC, stop
adding PETN and let the temperature rise to just under 60řC. Then begin
adding PETN again two spoons at a time and allowing it to dissolve until
all the PETN has dissolved
(d) With all the PETN now dissolved in acetone and the temperature held at
55řC, we will begin neutralizing the solution.
(e) Have both the blue and red litmus papers ready.
(f) Fill the graduated cylinder with the sodium carbonate solution that was
prepared in the tall form beaker.
(g) Keeping the contents of the large beaker in the 50ř to 60řC range, add to
it 10ml of the sodium carbonate solution (SCS). Insert a blue litmus paper.
if the paper turns red, add 10ml more of the SCS, and test again with the
litmus paper. Keep up this process of adding 10ml of SCS at a time, until
the litmus paper remains blue. When this happens, add a final 10ml of SCS.
Test with both the red and blue litmus paper. If neither paper changes
color, the solution is neutral. Turn off the hotplate.
(h) Immediately fill a bucket with two gallons of cold water. Pour the con-
tents of the large beaker into the bucket and stir. The PETN will now pre-
cipitate with its new fine crystalline structure.
(i) Test the water in the bucket with blue and red litmus paper. If the inst-
ructions in this text were followed carefully, there will be no reactions.
If they do react, then an error was made and salvaging the PETN will be
beyond the scope of this text. You will have to try again.
This concludes Step Three.
Step Four: Second Washing.
(a) This washing process is similar to Step Two, only we will be removing
acetone instead of acid from the PETN. When the contents in the bucket
(including the foam) have settled, pour off the water.
(b) Add two gallons of fresh water, stir, and allow to settle. If you smell
the water, you will notice a strong acetone odor. Continue the wash cycle
until the acetone odor is no longer apparent and then rinse the PETN two
more times to complete the washing.
(c) After the PETN has settled, pour off the water. Filter the PETN and allow
to dry to a 5 to 10 percent moisture content. The finished PETN should not
feel wet when a sample is squeezed between your fingers. When the PETN has
been dried, it will be ready for use. Store in a cool, dark place.
This concludes the manufacture of PETN.