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inspector071
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Nitrocellulose runaway, twice in a row
Tonight, I have tried twice to make some more guncotton. I have made about 20 grams of it in the last couple of weeks or so, but tonight I can't seem
to get it to work without it running away!
Earlier tonight I started with 8 grams of cotton, 48 g distilled nitric acid (haven't gotten my hydrometer in yet, but it's concentrated acid
distilled from sulfuric acid and potassium nitrate), and 52.4 g concentrated ~95% sulfuric acid. This is a roughly 1/12 ratio, and it worked just fine
the other day with 5.5 g cotton. My acids were chilled to 5 deg. C prior to mixing, and I used a chilled water bath to regulate the temperature. I
added the cotton and within seconds nitrogen dioxide started spewing from the center of my 250 mL beaker.
Just a few minutes ago I started with 6.5 g cotton, 37 g nitric acid, and 41 g sulfuric acid. Again, the acids were chilled to 5 deg. C before mixing.
After mixing them, I iced them to make sure they were cold. I used an ice bath this time to try and lower the temperature. This time I added the
cotton a little bit at a time. As soon as all had been added, again, nitrogen dioxide came forth from my beaker. After a few minutes it stopped,
leaving a black mixture of partially oxidized cotton and acids. What am I doing wrong? I'm not changing anything that I know of from just the other
day and a few weeks ago where I synthesized a bunch of the stuff with no problem at all.
On a side note, is there a method for determining nitrogen content of nitrocellulose? I'd be curious to know how nitrated I can get cotton with my
acids (if they ever stop running away).
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Bhaskar
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I am not that experienced in nitrating cellulose, i once experienced a runaway when i did it on a large scale, my doubt is that you should nitrate it
in different containers in smaller quantities. The nitric acid you are using is white fuming nitric acid and its quite a waste for such precious acid
as nitration is successful at the azeotropic concentration of nitric acid(about 68%~). Umm....thats all.
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disulfideprotein
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Okay... First... Well... I would recommend chilling to 0C, add the cellulose, wait about ten to twenty minutes. After such neutralise the acids and
wash then dry. Also use stoichiometric amounts so you have less of a chance of oxidation of the product.
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caterpillar
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OK, my experience. I've started with NC, and it was the first something more serious than black powder that I was able to make. The first: do not
spend time and efforts, making distillators. There is a nice way to make mixed acid without it. H2SO4, of course, plus Ca(NO3)2. So simple. I found
calcium salpeter in a simple shop with other fertilizers. it contents some water, and therefore real formulae is Ca(NO3)2.4H2O. heat it till all water
goes away. Do not worry, overheating here is quite impossible. Then break obtained solid mass to small pieces (not dust- 3-4 mm would be better). Put
it into conc H2SO4. I do not remember proper amount, but you may calculate it yourself. Assume all NO3 is replaced by SO4, and resulting mixed acid
contents 40 % of HNO3 and 60% of H2SO4. Let it stay for one night. you may filter it or simple remove upper liquid layer, leaving mass of CaSO4. Then
put cotton into it. Due to the consistence of cotton, you should put it into mixed acid for few minutes, than press (not very strong) it to remove
excess of mixed acid and put wet cotton into another vessel. let it stay for one night. Than wash it with large amount of cold water WARNING: do not
put large pieces into water, once when I did it such piece ignited under water! Take gloves and wash it quickly. Change water some times and use
solution of NaHCO3 (few percent) to neutralize rest of acids.
Women are more perilous sometimes, than any hi explosive.
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Pulverulescent
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| Quote: | | The first: do not spend time and efforts, making distillators. There is a nice way to make mixed acid without it. H2SO4, of course, plus Ca(NO3)2. So
simple. I found calcium salpeter in a simple shop with other fertilizers. it contents some water, and therefore real formulae is Ca(NO3)2.4H2O. heat
it till all water goes away. Do not worry, overheating here is quite impossible. Then break obtained solid mass to small pieces (not dust- 3-4 mm
would be better). Put it into conc H2SO4. I do not remember proper amount, but you may calculate it yourself. Assume all NO3 is replaced by SO4, and
resulting mixed acid contents 40 % of HNO3 and 60% of H2SO4. |
If you knew anything at all about inorganic chemistry you'd know that the above scheme is rubbish!
Because CaSO<sub>4</sub> is insoluble, very little reaction occurs when the dry salt is added to
H<sub>2</sub>SO<sub>4</sub>!
To liberate HNO<sub>3</sub> from calcium nitrate, the salt must first be dissolved in water before the addition of
H<sub>2</sub>SO<sub>4</sub> to the soln..
CaSO<sub>4</sub> precipitates leaving a soln. of nitric acid.
"I know not with what weapons World War III will be fought, but World War IV will be fought with sticks and stones"
A Einstein
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Pulverulescent
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| Quote: | | This time I added the cotton a little bit at a time. As soon as all had been added, again, nitrogen dioxide came forth from my beaker. After a few
minutes it stopped, leaving a black mixture of partially oxidized cotton and acids. What am I doing wrong? |
You're trying to nitrate a very impure cotton, or something that isn't cotton . . .
"I know not with what weapons World War III will be fought, but World War IV will be fought with sticks and stones"
A Einstein
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caterpillar
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Quote: Originally posted by Pulverulescent  | | Quote: | | The first: do not spend time and efforts, making distillators. There is a nice way to make mixed acid without it. H2SO4, of course, plus Ca(NO3)2. So
simple. I found calcium salpeter in a simple shop with other fertilizers. it contents some water, and therefore real formulae is Ca(NO3)2.4H2O. heat
it till all water goes away. Do not worry, overheating here is quite impossible. Then break obtained solid mass to small pieces (not dust- 3-4 mm
would be better). Put it into conc H2SO4. I do not remember proper amount, but you may calculate it yourself. Assume all NO3 is replaced by SO4, and
resulting mixed acid contents 40 % of HNO3 and 60% of H2SO4. |
If you knew anything at all about inorganic chemistry you'd know that the above scheme is rubbish!
Because CaSO<sub>4</sub> is insoluble, very little reaction occurs when the dry salt is added to
H<sub>2</sub>SO<sub>4</sub>!
To liberate HNO<sub>3</sub> from calcium nitrate, the salt must first be dissolved in water before the addition of
H<sub>2</sub>SO<sub>4</sub> to the soln..
CaSO<sub>4</sub> precipitates leaving a soln. of nitric acid.
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I do know chemistry! Where d'you find, that I added CaSO4??? I do add Ca(NO3)2, of course. Just because CaSO4 is insoluble, this reaction goes on and
at nearly all HNO3 is extracted. BTW, how d'you think the first fertilizer was made? I mean, Ca(H2PO4)2 superphosphate. Absolutely insoluble Ca3(PO4)2
reacted with H2SO4, producing much more soluble CaSO4. I realized, that similar method must work with Ca(NO3)2 too. You may dissolve Ca(NO3)2 in
water, but you'll det diluted mixed acide. It is useless to argue with experiments, that I made many times.
Women are more perilous sometimes, than any hi explosive.
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Ral123
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I think the insolubility of BaSO4 is exploited in some nitric acid synthesis.
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caterpillar
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There is one problem with Ca(NO3)2- I wanted to get conc HNO3, but got mess of crystals instead. You can get mixed acid with 40% of HNO3, but 50-60 %
of volume will be white mess- small cyrstals of CaSO4. Perhaps, using glass filter some more mixed acid could be obtained, but I simple threw it away.
Here is a good news too- I think, that during this process concentration of mixed acid goes up- CaSO4 surely contents some water- CaSO4*xH2O. I made
NG and NC in such way.
Women are more perilous sometimes, than any hi explosive.
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Pulverulescent
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Look, when calcium nitrate is added to sulphuric acid, the particles are immediately coated with CaSO<sub>4</sub>, preventing further
reaction.
The quantity of HNO<sub>3</sub> released is negligible.
CaSO<sub>4</sub>.2H<sub>2</sub>O is gypsum, a plaster used in interior walls!
It is also used to make Plaster of Paris, Ca(SO<sub>4</sub> <sub>2</sub>.H<sub>2</sub>O. | Quote: | | Do not worry, overheating here is quite impossible. |
FYI, calcium nitrate decomposes @~560°C!
Quicklime, NO<sub>2</sub> and O<sub>2</sub> are formed!
I suggest you read some basic inorganic chemistry texts!
"I know not with what weapons World War III will be fought, but World War IV will be fought with sticks and stones"
A Einstein
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simply RED
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If you mix dry lead nitrate with concentrated 96-98% sulphuric acid and heat this in boiling water bath for 20-30 minutes it gives quantitive yield of
insoluble PbSO4 and concentrated nitric acid that can be used for nitrating OH groups. I have done this multiple times, the problem is that much of
the nitric acid gets soaked in the precipitate, so you have to add twice as much sulphuric than needed and decant. The decanted solution (decant after
cooling!!!) is the ready nitrating mix. Works with barium nitarte too, no probem at all...
[Edited on 5-3-2012 by simply RED]
When logic and proportion have fallen sloppy dead...
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Pulverulescent
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| Quote: | | I made NG and NC in such way. |
You're lying!
Organic nitrates cannot be prepared by adding glycerine or cotton to mixtures of dry calcium nitrate in sulphuric acid!
"I know not with what weapons World War III will be fought, but World War IV will be fought with sticks and stones"
A Einstein
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Bot0nist
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| Quote: Originally posted by caterpillar | | Than wash it with large amount of cold water WARNING: do not put large pieces into water, once when I did it such piece ignited under water! Take
gloves and wash it quickly. |
Your kidding me right? I have made hobby sized rockets for many years and use homemade nitrocellulose lacquer on every one. So, suffice to say I have
made a lot of cellulose nitrate. Never once has it ignited during washing. Ever. The most you'll get is mild exertherm, not even sufficient to boil
the cold washing water. A wet piece of cellulose nitrate wont even deflagrate when exposed to direct flame for several seconds! I call bullshit.
STOP!
[Edited on 5-3-2012 by Bot0nist]
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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Adas
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As Pulverescent said before, make sure the stuff is really 100% cellulose. You can also try other nitration method - first put the cellulose into HNO3
and then slowly add H2SO4 - I heard this works very well.
Rest In Pieces!
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inspector071
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I'm using "natural, 100% pure cotton" balls.
I'm pretty sure they are indeed pure cotton as I have successfully nitrated it before. The product burned very quickly and left behind little to no
residue. I figured the black stuff in my runaway beaker was just charred cotton.
I'll give the cellulose + HNO3, then add H2SO4 a shot. I don't mind using my distilled concentrated nitric acid as I can always make more. I'd really
like to have as nitrated a product as I can possibly get. When using concentrated nitric (90%+) can I use a bigger ratio, say 1/8 or 9 and still get a
fully nitrated product? Seems as though a lot of these nitrations require empiric research since excess is often required to get decent yields.
What sources of pure cellulose do you guys use when making NC? And any way to analyze the nitrogen content of NC?
[Edited on 5-3-2012 by inspector071]
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Somniferrous
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| Quote: Originally posted by inspector071 | Tonight, I have tried twice to make some more guncotton. I have made about 20 grams of it in the last couple of weeks or so, but tonight I can't seem
to get it to work without it running away!
(...)
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In my dreams I always washed my cottonballs before nitrating, first with water, then with acetone.
I nitrated small batches with my proprietary NS (nitrating solution) in an ice bath. As I removed each cottonball from the NS with a hemostat, I
squeezed each one out with some tweezers then transfer it to a small cold water bath then to a larger cold water bath. From there it goes into a long
bath and finally in a slightly alkaline soln(H2O with a little bicarb).`
I also suspect that something has been added to the cottonballs may be causing that effect (assuming all other things are equal).
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inspector071
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| Quote: Originally posted by Somniferrous | | Quote: Originally posted by inspector071 | Tonight, I have tried twice to make some more guncotton. I have made about 20 grams of it in the last couple of weeks or so, but tonight I can't seem
to get it to work without it running away!
(...)
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In my dreams I always washed my cottonballs before nitrating, first with water, then with acetone.
I nitrated small batches with my proprietary NS (nitrating solution) in an ice bath. As I removed each cottonball from the NS with a hemostat, I
squeezed each one out with some tweezers then transfer it to a small cold water bath then to a larger cold water bath. From there it goes into a long
bath and finally in a slightly alkaline soln(H2O with a little bicarb).`
I also suspect that something has been added to the cottonballs may be causing that effect (assuming all other things are equal).
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I'll test a few of the cotton balls with some solvents to see if anything else is in them.
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caterpillar
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| Quote: Originally posted by Pulverulescent | | Quote: | | I made NG and NC in such way. |
You're lying!
Organic nitrates cannot be prepared by adding glycerine or cotton to mixtures of dry calcium nitrate in sulphuric acid!
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You are insulting me. They can. Read that I wrote more closely. I added cellulose or glycerine to MIXED ACID. This acig I got by adding dry Ca(NO3)2
to conc (probably 92%) H2SO4. After 12-20 ours of exposition upper liquid is just desired mixed acid and can be easely removed. Made experiment by
yourself, if you pretend that you are scientist in some way. I think, you beleive in your level of knowledge of chemistry too strong. "There are more
things on the Earth, on the heaven, Horatio, than any dreamt of in our philosophy". About ignition: In fact, there was no flame. There was violent
reaction, producing red smoke and leaving black coal instead of white cotton. Ant it occured just in water! I called it "ignition" only for
simplisity. Oxidisation, destruction would be better terms, probably.
Women are more perilous sometimes, than any hi explosive.
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Pulverulescent
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OK, I've prepared HNO<sub>3</sub> by distillation from KNO<sub>3</sub>/H<sub>2</sub>SO<sub>4</sub>
mixtures only!
It has always, though, been my understanding that nitrate salts whose sulphates are insoluble react only to a small extent with
H<sub2</sub>SO<sub>4</sub> before the particles become coated by the insoluble sulphates.
If you, or sRED can produce pictorial proof that organic nitrates can be prepared from dry Ca, Pb or Ba nitrates in
H<sub>2</sub>SO<sub>4</sub> I will quickly lose my scepticism.
It would seem though, at best, a remarkably inefficient method for preparing HNO<sub>3</sub>, nitro or NC!
"I know not with what weapons World War III will be fought, but World War IV will be fought with sticks and stones"
A Einstein
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inspector071
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And isn't the mixed acid nitration preferred over a nitrate salt/sulfuric acid mix for NC? I would like to learn more about the different forms of
nitrations, because, as I understand it, there are many different methods for different species being nitrated. RDX apparently decomposes in H2SO4 and
must either be nitrated via pure HNO3 or less pure HNO3 and glacial acetic acid as a dehydrant. Picric acid and ETN both have syntheses that seem to
favor the nitrate salt/H2SO4 method, while nitroglycerin uses a standard mixed acid.
I'm currently distilling more HNO3 as we speak. My cotton has been washed thoroughly and is now drying. Should be able to make some NC tonight.
[Edited on 5-3-2012 by inspector071]
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caterpillar
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| Quote: Originally posted by Pulverulescent | OK, I've prepared HNO<sub>3</sub> by distillation from KNO<sub>3</sub>/H<sub>2</sub>SO<sub>4</sub>
mixtures only!
It has always, though, been my understanding that nitrate salts whose sulphates are insoluble react only to a small extent with
H<sub2</sub>SO<sub>4</sub> before the particles become coated by the insoluble sulphates.
If you, or sRED can produce pictorial proof that organic nitrates can be prepared from dry Ca, Pb or Ba nitrates in
H<sub>2</sub>SO<sub>4</sub> I will quickly lose my scepticism.
It would seem though, at best, a remarkably inefficient method for preparing HNO<sub>3</sub>, nitro or NC!
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I do not see, what "pictorial proof" means. Assume I'll show you snapshot of a bottle with some liquid and crystalline mess- is it proof or not? How
could you know, what actually is in there? May be, NaCl + some water. Make your own experiment, it is very simple. You undestanding about diffusion is
wrong. It goes, not very fast but goes. Find an article about superphosphate- it is made by similar way. Moreover, too thin dust makes problems- one
needs to get rid of crystalline mess. It is not very efficient method, yeah, because I threw away lots of mixed acid with CaSO4. It is very efficient
method, on the other hand, because I was able to bypass distillation. Moreover, I believe (only believe! I do not know) that this method increases
quality of mixed acid- CaSO4 binds some H2O.
Women are more perilous sometimes, than any hi explosive.
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caterpillar
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| Quote: Originally posted by inspector071 | And isn't the mixed acid nitration preferred over a nitrate salt/sulfuric acid mix for NC? I would like to learn more about the different forms of
nitrations, because, as I understand it, there are many different methods for different species being nitrated. RDX apparently decomposes in H2SO4 and
must either be nitrated via pure HNO3 or less pure HNO3 and glacial acetic acid as a dehydrant. Picric acid and ETN both have syntheses that seem to
favor the nitrate salt/H2SO4 method, while nitroglycerin uses a standard mixed acid.
I'm currently distilling more HNO3 as we speak. My cotton has been washed thoroughly and is now drying. Should be able to make some NC tonight.
[Edited on 5-3-2012 by inspector071] |
Distillation was always problem for me. I think, that if it can by bypassed, it must be done. Picric acid can be obtained by KNO3 (or NaNO3) + H2SO4.
NC reqires liquid mixed acid, therefore method that I described (Ca(NO3)2 + H2SO4) is good here. Nitrourea can be obtained by HN4NO3, dissolved in
H2SO4. But RDX and HMX, yeah, they surely require HNO3 and here distillation is a must (may be extraction by CH2Cl2, but even in this case one needs
distillation)
Women are more perilous sometimes, than any hi explosive.
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simply RED
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You may make the very very simple experiment: take powdered dry lead nitrate and twice the neeed amount conc H2SO4. Mix well in a small jar with screw
cap, put a piece of nylon on the cap not to pass nitrous fumes. Screw the cap and transfer the jar to 100 degC water bath for 20-30 minutes. Agitate
the jar by hand in every 1-2 minutes. You will see the insoluble heavy lead sulphate forming on the bottom. After this, cool the mix and
decant/filter. This is perfect mixed acids for nitrating organics!
You will be left with a quantitive (more than 80% in any case) yield of lead sulphate precipitate that can not be mistaken with anything else.
Extremely simple and always works fine...
Also perfect to use lead nitrate to "add power" to a nitrating mix with commercial 60-65% HNO3. Always decant the mixed acids as the presence of lead
sulphate may (and has!) lead to runway!
By the way, what is the solubility of calcium sulphate in conc. sulphuric acid? I never got quantitive (theoretic) yield with calcium nitrate (it
works too but with much lower yield), lead nitrate works best.
[Edited on 6-3-2012 by simply RED]
When logic and proportion have fallen sloppy dead...
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caterpillar
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May be, lead nitrate works too. But calcium nitrate is much cheaper and can (well, could some years ago, when I was young and made such experiments)
be obtained as a fertilizer. When I first time met that wonderful shop, where I was able to buy some reagents, there was some restrictions. I couldn't
buy acids (but H2SO4 92-94% was availible across the street as a liquid for accumulators!) but I was able to buy lead nitrate. I took 100 gr and
wasted it during my first attempts to prepare picric acid and its salts. Some years later when I made stiphnic acid and went to aforementioned shop,
all salts of nitric acid was in list of reagents not for free sale (one had to bring some paper from an organisation- a scool, laboratory and so on).
I could buy lead acetate, but according one thick book I had to use only lead nitrate for preparation of lead stiphnate. Therefore I made ammonium
salt of stiphnic acid and exploded it, using TATP as detonator. I do not know about the solubility of calcium sulphate in conc. sulphuric acid. It
should be low- few gr per 1liter, no more. One has to wait, wanting to extract more HNO3, using Ca(NO3)2 and H2SO4. May be, exposition in hot water
would help. But I simple waited for a night. After it I decanted the upper layer.
Women are more perilous sometimes, than any hi explosive.
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simply RED
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ftp://ftp.igt.ethz.ch/PublicWorld/kostas.serafeimidis/solubi...
Very good article!
In discussion, the truth is born...
Maybe the sulphate covering of the crystals is penetrable by sulphuric acid without dissolving it (or through some kind of mass excahge) and the
sulphuric acid can continue reacting with the nitrate, as water reacts with iron through the insoluble rust. As I said with lead nitrate the reaction
goes to completion within 30 minutes at 100 degrees C. And you are left with shitload of PbSO4 at the bottom of the jar that can easily plug the drain
canal (believe me  )... Just try it to see what I mean!
Maybe lead nitrate works better because the "heavy" lead sulphate falls at the bottom of the jar and separates from the mix but calcium sulphate forms
small crystals suspension in the solution? Or maybe they work exactly the same only I did not wait long enough in my experiments with the calcium
nitrate.
When logic and proportion have fallen sloppy dead...
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