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quicksilver
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Wash with distilled saline water approximate 2% weight stabilizer,, 5% anti-acid (Naoum, Nitroglycerin & Nitroglycerin Explosives). The allow
exposure for approx 48-96 hours, replace, until the NG is neutral to litmus. Upon completion, store in absorbent with anti-acid and stabilizer
(Diphenylamine, urea,centrelite, etc, etc) or, if to be kept as liquid, retain under saline water with anti-acid (sodium carbonate, etc).
NOTE: Neutral means 7 - not 7.5. The "salt water" will clean up the NG to a very clear material, pulling any water from it.Stabilizers should not be
applied too heavily. There is even a B vitamin that will act as a stabilizer (Betaine).
[Edited on 13-3-2012 by quicksilver]
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Bhaskar
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Quote: Originally posted by quicksilver  | Wash with distilled saline water approximate 2% weight stabilizer,, 5% anti-acid (Naoum, Nitroglycerin & Nitroglycerin Explosives). The allow
exposure for approx 48-96 hours, replace, until the NG is neutral to litmus. Upon completion, store in absorbent with anti-acid and stabilizer
(Diphenylamine, urea,centrelite, etc, etc) or, if to be kept as liquid, retain under saline water with anti-acid (sodium carbonate, etc).
NOTE: Neutral means 7 - not 7.5. The "salt water" will clean up the NG to a very clear material, pulling any water from it.Stabilizers should not be
applied too heavily. There is even a B vitamin that will act as a stabilizer (Betaine).
[Edited on 13-3-2012 by quicksilver] |
thank you!
Are stabilizers compulsary even for short term purposes?
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Bot0nist
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It is not a bad idea, but is really important in longer term storage, IIRC. We are getting way off topic here though. I'm not scolding anyone, because
I know more than anyone how easy a discussion can stray. For future searcher's sake can we please post NG questions in one of the many corresponding
threads.
U.T.F.S.E. and learn the joys of autodidacticism!
Don't judge each day only by the harvest you reap, but also by the seeds you sow.
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quicksilver
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| Quote: Originally posted by Bot0nist | | It is not a bad idea, but is really important in longer term storage, IIRC. We are getting way off topic here though. I'm not scolding anyone, because
I know more than anyone how easy a discussion can stray. For future searcher's sake can we please post NG questions in one of the many corresponding
threads. |
Personally, I agree. - with one caveat. Some materials are VERY tough to get the acid out and neutralized. These are OFTEN crystalline shaped
materials, but not always. IMO - the cardinal rule is to get that synthesis to a 7 (neutral) pH. If the material is (especially) a crystal or a liquid
- - I would put a stabilizer in there IF (1) I was making more than I was going to use that moment, (2) I would not consider making a large amount -
period. (3) - one of the most effective methods of getting acid out of a crystal is re-crystallization.
NG (again IMO) should be made in very small amounts. It's an easy material to make - but it can also go badly very quickly from all sorts of things -
even UV light.
There are few experiments that you can't do with a few milligrams other than end up blind or learn to type with one hand.
I am not a young guy. Frankly I am a Hell of a lot older than the overwhelming majority of people on this Forum. I also know that I am not the
wisest. But I do know that all ten fingers are typing this now. The interest in Energetic Materials is similar to an interest in firearms. The first
thing and the last thing to learn and continue with - is how not to fuck up while having a hobby that has and will continue to change and DEMANDS
maturity or extracts a vicious price for a blunder.
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TheMessenger
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| Quote: Originally posted by niertap | In most energetic material synthesis' 70% HNO3 is used. Why doesn't everyone just use KNO3 or NaNO3? There will be a considerable amount of water
that will not have to be removed from the reaction, decreasing the amount of H2SO4 needed.
A 3.8L jug of 98% H2SO4 can be purchased from the hardware store for around $25. Why would someone not in an analytical setting use anything
different?
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All of us who distill our own HNO3 use 90%+ concentration. Reactions done with HNO3 instead of nitrate salts have 200-300% high yields. ETN
synthesized with fertilizer grade KNO3/H2SO4 results in a yield of around 1E > 0.5ETN while ETN synthesized with HNO3/H2SO4 results in a yield of
1E > 2ETN by weight.
You have been SERVED by TheMessenger.
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BromicAcid
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| Quote: Originally posted by caterpillar | | How do you determine this yield? It can be calculated in different ways. You need generally more H2SO4, and according to it yield will be, yeah,
lower. |
Can't speak for Pulverulescent but I can't think of any reasonable chemist that would calculate yield based on anything BUT the key raw. In which
case concentration be damned, the amount of sulfuric acid would not make a lick of difference unless you can't recover your product out of it in which
case it really wouldn't count as yield would it?
I certainly agree on the front of purity however as a star in favor of using nitric acid. In terms of energetics as far as I know you always want to
maintain the best purity you can in order to maintain consistency of your final product and reduce the chance of decomposition (unintentional
decomposition of course). Certainly most of us have heard of a few percent of this or that stabilizing or conversely catalyzing the decomposition of
a compound. Be your cation ammonium, sodium, potassium, etc. that unquestionably introduces another variable into the equation.
Edit: Counterpoint to the title, Dinitrogen pentoxide is an excellent nitronium ion source, why not use it?
[Edited on 3/18/2012 by BromicAcid]
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AndersHoveland
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Yes, N2O5 is an excellent nitronium cation source, ideal in several ways. But it also has some disadvantages: it is a relatively sensitive explosive,
it is unstable and will decompose after about 2 days at room temperature, it is difficult to prepare and is not commercially available.
For these reasons, nitronium tetrafluoroborate, NO2BF4, is usually preferred. Another less commonly thought of disadvantage to N2O5 relative to NO2BF4
is that the nitrate anion itself can actually be problematic in certain extreme reactions.
For using N2O5, one possible method involves using pressurised liquid CO2 as the solvent.
https://www.sciencemadness.org/whisper/viewthread.php?tid=17...
http://www.sciencemadness.org/talk/viewthread.php?tid=17304
The danger, of course, would be that as soon as the mixture was depressurized, the CO2 would immediately boil out, leaving the solid explosive N2O5.
The sudden decompression could potentially trigger detonation.
SO2 would be much easier to liquify, but N2O5 would probably oxidize the SO2 to nitrosyl pyrosulfate, (NO)2S2O7
Preparation of Nitronium Tetrafluoroborate
Nitronium tetrafluoroborate is a useful nitrating agent which has several advantages over nitric acid. There are also some nitration reactions where
the presence of the nitrate ion would prevent the desired product from forming. Nitronium tetrafluoroborate is a solid ionic compound, with the
formula NO2(+) BF4(-). Nitronium tetrafluoroborate can be prepared by adding a mixture of anhydrous hydrogen fluoride gas and boron trifluoride to a
solution of either highly concentrated nitric acid or nitrogen pentoxide dissolved in nitromethane.
WARNING: Rubber gloves, an apron, and a plastic face mask are strongly recommended. All operations should be carried out in a hood. If hydrogen
fluoride comes in contact with the skin, the contacted area should be thoroughly washed with water and then immersed in ice water while the patient is
taken to rushed to the emergency department. Burns caused by hydrogen fluoride may not be noticed for several hours, by which time serious tissue
damage may have occurred.
Note: Any operations involving liquid hydrogen fluoride must be carried out with equipment resisting hydrogen fluoride, such as fused silica,
polyolefin, monel steel, or teflon. Kel-F grease is recommended for ground-glass joints. Nitronium tetrafluoroborate slowly attacks silicone stopcock
grease, causing air to enter the flask. After completion of the reaction, all equipment should be washed with plenty of water.
A 1-Liter three-necked polyolefin flask is provided with a short inlet tube for nitrogen, a long inlet tube for gaseous boron trifluoride, a drying
tube, and a magnetic stirring bar. The flask is immersed in an ice-salt bath and flushed with dry nitrogen. Under a gentle stream of nitrogen and with
stirring, the flask is charged with 400 ml. of methylene chloride, 41 ml. (65.5 g., 1.00 mole) of red fuming nitric acid (95%), and 22 ml. (22 g.,
1.10 moles) of cold, liquid, anhydrous hydrogen fluoride. 5. It is convenient to condense anhydrous hydrogen fluoride, b.p. 19.5°, from a cylinder
into a small calibrated polyolefin flask immersed in a mixture of dry ice and acetone. As hydrogen fluoride is very hygroscopic, it should be
carefully protected from atmospheric moisture, preferably by maintaining an atmosphere of dry nitrogen over it, otherwise by means of a drying tube.
The hydrogen fluoride is then simply poured into the reaction flask.
Gaseous boron trifluoride (136 g., 2.00 moles) from a cylinder mounted on a scale is bubbled into the stirred, cooled reaction mixture. (The
temperature of the reaction is not critical, but the reaction is slower at higher temperatures because of the lower solubility of boron trifluoride in
the solvent). The first mole is passed in rather quickly (in about 10 minutes). When approximately 1 mole has been absorbed, copious white fumes begin
to appear at the exit, and the rate of flow is diminished so that it takes about 1 hour to pass in the second mole; even at this slow rate, there is
considerable fuming at the exit. After all the boron trifluoride has been introduced, the mixture is allowed to stand in the cooling bath under a slow
stream of nitrogen for 1.5 hours. The mixture is swirled, and the suspended product is separated from the supernatant liquid by means of a
medium-porosity, sintered-glass Buchner funnel. Note that since free hydrogen fluoride is no longer present, filtration can be carried out with glass
or porcelain equipment.
The gooey solid remaining in the flask is transferred to the funnel with the aid of two 50-ml. portions of nitromethane. The solid on the funnel,
nitronium tetrafluoroborate, is washed successively with two 100-ml. portions of nitromethane and two 100-ml. portions of methylene chloride. In order
to protect the salt from atmospheric moisture during the washing procedure, suction is always stopped while the salt is still moist. The moist salt is
transferred to a round-bottomed flask and dried by evaporating the solvent. At the end of the procedure the flask can be gently heated to 40–50°C
(Nitronium tetrafluoroborate is thermally stable up to 170°. Above this temperature it starts to dissociate into nitryl fluoride and boron
trifluoride.) The yield of colorless nitronium tetrafluoroborate is 85–106 g. (64–80%) It is stored in a wide-mouthed polyolefin bottle with a
screw cap. The edge of the cap is sealed with paraffin wax after it is screwed on. Nitronium tetrafluoroborate is very hygroscopic. It is stable as
long as it is anhydrous, but it is decomposed by moisture, and all transfers should be in a dry box.
Nitronium tetrafluoroborate slowly attacks polyethylene and polypropylene, but apparatus made of these materials will last for several preparations of
the salt.
The last part of the procedure can be used to purify nitronium tetrafluoroborate that has picked up water on standing. The impure salt is washed twice
with nitromethane, twice with methylene chloride, and is dried under reduced pressure.
Making Boron Trifluoride BF3
Boron trifluoride is a very toxic gas, which readily reacts with water to form metaboric acid and Fluoroboric acid, which then can further hydrolyze
if excess water is present. It is a strong fluoride ion abductor, meaning it will pull a fluorine atom from many covalent compounds to form the
tetrafluoroborate anion (BF4-), while leaving a positively charged cation. However, boron trifluoride is not as powerful of an abductor as antimony
pentafluoride, as demonstrated by its unreactivity towards trichlorofluoromethane.
Boron trifluoride may be prepared by heating a mixture of boric oxide and calcium fluoride with concentrated sulfuric acid. It may also be prepared by
mixing 5 parts of potassium borofluoride (KBF4) with 1 part finely powdered boric oxide, then heating with concentrated sulfuric acid. The boron
trifluoride, can be collected over mercury. Potassium borofluoride may be produced by heating together 2 parts boric acid, 5 parts CaF2, and 10 parts
conc H2SO4. The liquid is then cooled and filtered, and a solution of a potassium salt is added. Potassium borofluoride precipitates out, and may then
be recrystallized from hot water. By this method it can be prepared as anhydrous hexagonal crystals. If it is prepared instead from hydrofluoric acid,
boric acid, and K2CO3, a gelatinous mass forms instead, which however forms cubic octahedral and cubic dodecahedral crystals when heated to 100degC.
Boron trifluoride also results from heating a mixture of boric oxide and calcium fluoride to a white heat in an iron pipe. Heating solid borofluorides
to red heat, boron trifluoride is evolved, leaving behind metal fluorides.
[Edited on 18-3-2012 by AndersHoveland]
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AndersHoveland
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Here is a different method for preparation of nitronium tetrafluoroborate:
| Quote: | Prepare a mixture of 8.8 g of hydrofluoric acid and 40 g of ethylnitrate in 300 mL of dry nitromethane. Place this mixture in a salt-ice bath and cool
to 10 C. Slowly add 100 g of boron trifluoride to the mixture while keeping the temperature between 10 and 15 C. A few minutes after the addition
filter to collect the crystals of nitronium tetrafluorate that form. Wash the crystals with two 400 mL portions of a 1:1 mixture of methylene chloride
and nitromethane, and then with one 400 mL portion of methylene chloride.
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The ethyl nitrate being made by nitration on ethanol, of course.
Not sure what exactly they mean by "hydrofluoric acid", might be better to pass the equivalent amount of HF gas into the reaction (using plastic
containers and tubing, and taking the appropriate precautions).
[Edited on 24-8-2013 by AndersHoveland]
I'm not saying let's go kill all the stupid people...I'm just saying lets remove all the warning labels and let the problem sort itself out.
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