Nitrocellulose main query.

[Choppy]

Okay, so I've been mauling over to post here for a while now about this, so I am going to. I have done quite a fair bit of research on this, and a few attempts, and even asked a very familiar chemistry teacher I know, and even he couldn't give me an answer, so, let's see.

By using sodium nitrate, with 98% conc sulphuric acid it gives nitric acid and sodium sulphate.

2NaNO3 + H2SO4 ----> Na2SO4 + 2HNO3

Right, so, its a 2:1 ratio of Nitrate to sulphuric. Now for the maths.

If I use, say, 50grams of Sodium nitrate. Change that into moles,
50/NaNO3.... 50/85 = 0.588 moles.

2:1, so 0.588/2 = 0.279 of Sulphuric acid, now to change into mass..

0.279 x H2SO4....0.279 x 98 = 27.34 grams of sulphuric.. which, using 1.84gcm-3 as density, 27.34/1.84 = 14cm3 of sulphuric acid.

I've tried this. And it fails, it turns into a very thick gunge, which is very hard to submerge the cotton in for the nitration stage. I dont understand quite why that is. Anyway, I stumbled across this statement on http://www.powerlabs.org/chemlabs/nitrocellulose.htm and this guy states
An alternate nitrating mix is made by adding 1gram of finely powdered Potassium or Sodium Nitrate (KNO3/NaNo3) for every 3.325g (3.819ml) of cold concentrated Sulphuric Acid (H2SO4),

So, how is this correct. I dont understand, because surely if I am using the correct molar amounts in relation to one another, then it will create the 2 moles of HNO3 that I want.

Clarification would be highly appreciated.

[peppovsky]

...So now you meet the point where science becomes interesting - theory is good and beautiful and all, but real world acts a little different (something to do with Murphy :rolleyes: ) - working in the laboratory (or @ your home) is NEVER a perfect condition, and things will ALWAYS go different then what you plan in mind. The amount of difference depends, surprisingly enough, on your experience and skills. Practice more - get better results! ;)

Now for your specific query - Did you add the NaNO3 slowly, or all at once? Throwing KNO3/NaNo3 to H2SO4 quickly results in, as much as I remember, slime. Try adding the NaNO3 really slow - over 30 mins or so with this amount (50g).

For the record, you haven't reported of any NO2 gas fuming out, so maybe I'm mistaken. That, of course, doesn't mean anything for what I've said in the first paragraph.

[The_Duke]

NaNO3 + H2SO4 = HNO3 + NaHSO4 :rolleyes:

[Rbick]

Choppy, I had the same problems with making Nitrocellulose using the KNO3 nitrating method. I found that it is in fact from adding the KNO3 too quickly that the nitrating mixture becomes a thick paste. As peppovsky said, add it slowly, and make sure the temp does not raise above 40 degrees C.

The ratio you stated is approx. the amount I use, and it results in some pretty good quality NC. Of course you could get better quality if you get some HNO3 :rolleyes: Good luck.

[Choppy]

Ahh excellent, thanks for that Peppovsky and Rbick. Okay. I'll add it in very slowly then, taking a good 30 minutes for just that stage, or even longer depending on the situation.

I did some of the calculations for the equation that the duke stated.

NaNO3 + H2SO4 ---> HNO3 + NaHSO4

Which turns out, if I use 50grams of NaNO3, then i'll need to use 57.64 grams of sulphuric (31cm3 of sulphuric acid). (Calculations done same way as above)

I'm going to try both the equations, doing the 50g:57g, and the 50g:27g . I am following the way that it equation states, not doing the 1 (nitrate) : 3 (sulphuric) as that website stated, because I can't see the sudden change between 2:1 or 1:1 suddenly to 1:3 !!

I've had a few runaways, but that was only when not using a water bath when adding the cotton in, I've had a few successful batch, but I truely wish to have the best stuff, absolutly no residue and a complete combustion of the product.

[peppovsky]

Good luck.
In the future, avoid not using an ice bath - homemade explosives synth is too damn dangerous as it is ;)

[ponder]

"Which turns out, if I use 50grams of NaNO3, then I'll need to use 57.64 grams of sulphuric (31cm3 of sulphuric acid). (Calculations done same way as above)."
Wouldn't that mean that your nitric is coming to around the conc of the H2SO4 (98%). If that is so the even using the 35% to 65% would give you the tri nitrate in stead of the hexa nitrate .

[Dr. Hextromeister]

Ammonium Nitrate is your friend.....

As previously stated, KNO3 needs to be added slowly over a period of around 15 minutes to allow for the right conditions to work with. Stirring while being slowly killed by nasty vapors isn't such a good thing to do.... So have your gas mask at the ready.

[Mesh5]

If you're making a small amount of NC (4g orso) KNO3 doesn't need to
be added slowly. You won't need any temp. controll whatsoever.

This (http://www.geocities.com/brainfevert/index6.html) is a nice and simple tut. Don't use toilet paper though.

EDIT: You're using 50g of NaNO3 on 30ml of H2SO4!? That's waay too much NaNO3. 20-30g of -NO3 on
30ml of H2SO4 has always done the trick with me. Let it nitrate for 3 hours and you're sure to have
NC that will poof when you light it. Make sure to clean it of acids properly or it will NEVER dry. Drying can
be done in an oven heated to 100C with hot air (turn the oven off and put your NC in).

I think I can (sort of) explain what the mistake is you made. You calculated your quantities to fabricate
HNO3 I'm guessing that the HNO3 this method makes is diluted with water. That's why you need H2SO4
to get the water out sort of (I'm not sure, fact is you NEED the H2SO4 in your mix). The problem lays
not at all in your nitrate-salt.

w00t first post :D.

[Choppy]

"Which turns out, if I use 50grams of NaNO3, then I'll need to use 57.64 grams of sulphuric (31cm3 of sulphuric acid). (Calculations done same way as above)."
Wouldn't that mean that your nitric is coming to around the conc of the H2SO4 (98%). If that is so the even using the 35% to 65% would give you the tri nitrate in stead of the hexa nitrate .

I dont quite follow what you mean, I'm afraid. Are you saying that by using the quanitites which I have I am basically creating a very strong nitric in which will only produce a trinitrate instead of the better hexanitrate?

I've been drying the stuff for a week or so now, and it burns, fast, but with a bit of residue which is annoying. I believe it may still be a little damp, or just didnt nitrate properly. There was still a fair porportion of undissolved sodium nitrate in the sulphuric solution, so I have been advised to basically anhydrate it by heating to like 100*C, obviously not decomposing as it doesnt untill around 300 odd.

I used the 50g nitrate:57g sulphuric (31ml) ratio, what is it which works best? I should be getting some AN and KNO3 soon too.

[ponder]

All I was tyring to say was that if your are using to much nitric acid in ratio to sulphuric then you might not get the best nitration results . Meaning that you will get the tri-nitrate version rather than the hexa-nitrate.

As for the residue left it should not be any salts from the nitrating mixture as they will be soluble and wash of when you are washing to get rid of th excess acid.

If it is taking long to dry you probably still have some acid in your nitrocellulose , when that had happened to me i had had the same probs that you are having.

[me234]

Basically what I understand you to be doing is making some ~98 % nitric acid, and trying to use that as a nitrating agent for cellulose. Also you not quite sure why Powerlab's method uses more sulphuric than stochiometrically required right?

Well, first of all, using so much nitrate salt with so little acid (whether it's the right amount or not) is going to give you problems (had them myself). Secondly, Instead of a straight nitric acid bath, why not try a nitric acid / sulphuric acid bath as with most nitrate esters?

This is what Powerlab's method uses: You add enough sulphuric acid to react with the nitrate salt to give you nitric acid, but then you add further sulphuric acid to give you a nitric/sulphuric acid nitrating mixture.

This gives you at least 2 advantages: Firstly, you get to add extra sulphuric acid which gives you plain old extra volume of solvent to dissolve all your salt into, and; Secondly, straight nitric acid (ignoring any unconverted sulphuric acid) fails to give you the nitronium ion NO2+ (which is the true nitrating agent) in any great quantity (sorry, forgot how to sub- and superscript).

Adding conc. sulphuric to nitric acid dehydrates the nitric to give the nitronium ion which then goes on to form the nitrate esters. So extra sulphuric (ala a sulphuric/nitric bath) generally works better IMO.

Good luck with the synths

Sorry about the lack of mutiple paragraphs NBK

[Alexires]

Just to add on to what me234 is saying, Sulfuric Acid also acts to "suck up" the water created by reacting the nitric acid with the cellulose.

What you should do is this. Write out your equation for making nitrocellulose. Calculate how much water it produces, then work out how much sulfuric acid you need to make the required nitric + how much sulfuric acid you need to absorb all the water + a little more (not too much, but just in case everything isn't absolutely dry, etc).

I'll leave you to the stoichiometry bliss that is chemistry *grin*.

[bobo]

Guideline number one when doing nitrations is that you need excess sulfuric, but not so much excess nitric. Not so much as in not 3eq of nitric. 1.2 eq of nitric would be far more convenient, or 1.5 eq perhaps. Sulfuric is used in great excess some of the time. Salts make things more viscous, their concentration should be minimized.

I hate using nitrate salts directly, by the way. Nitrocellulose from cotton is difficult because the cotton is too heterogeneous, making a sludge is just asking for trouble. This reaction can runaway after unexpectedly long times. I obtained partly nitrated cotton, too. You have to have excellent stirring capabilities, a rotary drill or something like that is a good idea.

Anyway, it might do to re nitrate the partially nitrated cotton to obtain complete esterification. Unlike aromats, nitroesters don't generally go more difficult as nitro content goes up.

[Choppy]

1. NaNO3 + H2SO4 ---> HNO3 + NaHSO4
2. 2HNO3 + C6H10O5 ---> C6H8(NO2)2O5 + 2H2O

So, after working around the last 1-2 weeks with some research both on the net and actually carrying some through, I firstly decided to use the 30g (Nitrate ):90g (Sulphuric) t at Powerlabs suggested. The main problem was, even though I managed to reduce the bisulphate crystals, the actual nitration mixture just wasn't in enough mass to nitrate the cotton that I submerged in it for 4-6 hours. It ended up being okay, didnt burn down to nothing which was dissappointing, but I detonated it with some HMTD that I made up. Not that good. And rather dissappointed.

Very pleased that the actual chemical reasoning has been explained, stops my on going fight that the equation must be correct to follow stoichmetrically. Anyway, I would preferably like to find the exact quantites (for self satisfaction) of each reactant, so I can actually scale up, or scale down making nitrocellulose.

Alexires, I tried having a bash at doing some calculations for the method in which you suggested, but I couldnt make it work without manipluating some of relative molecular mass of the compound. I couldnt get the ratio correct, because two of the things are being mixed up, its not as easy as the classic "how much NaCl is made with 92grams of sodium" because theres one product, with two products its not doable. Or is it?

I have a new plan however. If I take a round bottom flask, clamp it up, and pour in my 60cm3 (90g) of sulphuric, and then add in the sodium nitrate, using around 20-30gs of it, take a bunsen fitted to a butane canister, using a g cramp (oh yes, cramp, GCSE resistant materials taught me that one) as a regulator, then if I heat the mixture gently the nitrate will dissolve much easier with less hasle. If I then took this, let it cool and added the cotton in for nitration then wouldnt that be successful, as the desired amounts would actually be in solution?

I will try this, and get back about it.

[Alexires]

Choppy - *sigh* Ok then. Lets see how we go.

Lets say we want to make one mole of nitrocellulose. That means we need 1 mole of cellulose (1:1 ratio from the equation 2HNO3+C6H10O5 --> C6H8(NO2)2O5 + 2H2O).

1 mole of cellulose = 162.1g
2 moles of HNO3 = 126g

Ok, so you need 126g or 2 moles of HNO3.

As we know that NaNO3 reacts with H2SO4 in a 1:1 ratio to give 1 mole of HNO3, then we need 2 moles of NaNO3 and 2 moles of H2SO4.

2 mole of NaNO3 = 169.8g
2 mole of H2SO4 = 196.04g

That is the basic reaction. Of course, we now need some more H2SO4 to soak the H2O made during the NC reaction. We know that 2 moles of H2O are produced for every mole of NC.

Now, I don't know how much water Sulfuric Acid is capable of absorbing, but I believe it is two moles for every mole of Sulfuric acid due to this equation:

H2O + H2SO4 --> H3O+ + HSO4-

then

HSO4+ + H2O --> H3O + SO42-

So, assuming this is correct, we now need another mole of H2SO4 to absorb the water created. This ends up with 294.06g of H2SO4 in total.

So I would guess this. Add 169.8g of dry pure NaNO3 to 300g of 100% sulfuric acid. Then, when you are ready, add 162.1g of pure cellulose to the sulfuric acid mixture. This should be enough sulfuric to a) react with the NaNO3, b) soak up the excess water, c) with a little left over.

Given the density of 100% H2SO4, this is about 163mL of H2SO4.

I've looked over this a few times, and I'm pretty sure its ok. The only problem could be equilibrium. If the Nitrate Salt/Sulfuric reaction is an equilibrium reaction, you are going to need more H2SO4 to push the reaction towards the Nitric acid side. Same with the NC reaction.

The floor is now open for opposing view points *grin*.

[Choppy]

Ahh excellent maths, however I am a tad confused on the use of the RMM (relative molecular mass, ie Fe = 56g per mole, being used as the mass, in this case you use H2SO4 = 98 per mole, doubled up to 168g per mole) seeing as I usually use the mass = moles x RMM, so RMM = mass/moles, and so, moles = mass/RMM.

But anyway, I got myself over the last week a good set of 0.01 scales, and I performed the experiment, using a 30g-90g ratio of nitrate:sulphuric, and even after adding in the nitrate slowly as suggested by many above, there was still wayyy to much undissolved nitrate.

I am guessing, that my sodium nitrate is way too hydrous for the reaction. I still managed to, (what I believe is) fairly well nitrated cotton. I will have to test this out. I'm thinking maybe heat my nitrate up to the level at which it will remove the water from the compound, and give a more solube nitrate..

[ponder]

"Now, I don't know how much water Sulfuric Acid is capable of absorbing, but I believe it is two moles for every mole of Sulfuric acid due to this equation:

H2O + H2SO4 --> H3O+ + HSO4-

then

HSO4+ + H2O --> H3O + SO42-"
That has nothing to do with the dehydratind power of the sulphuric acid ,in those equations you are just representing the equation of a di basic bronsted-lawry acid .

[FUTI]

Are you guys sure about undisolved nitrate? I have seen KHSO4 precipitating during making "chrom-sulfuric-acid" (God knows how you call that in English), so maybe you have seen the same thing just didn't understood it clearly. Did you check is that undisolved thing mostly nitrate or sulfate?

[Alexires]

Ok ponder, go for it. How much water does sulfuric acid absorb? I said I didn't know, put forward an assumption (stated) based on some research.

Where is your supporting documentation/argument besides "No it doesn't".

Considering you can't spell "Bronsted-Lowry" correctly, I don't see how you expect me to believe you :rolleyes:

[ponder]

Ok ponder, go for it. How much water does sulfuric acid absorb? I said I didn't know, put forward an assumption (stated) based on some research.

Where is your supporting documentation/argument besides "No it doesn't".

Considering you can't spell "Bronsted-Lowry" correctly, I don't see how you expect me to believe you :rolleyes:

Sorry for being off topic . I have not experimented with the dehydrating power of sulphuric acid but you could do a few simple experiments to find out , for example you can leave a known amount of sulphuric acid in air and see how much water it absorbs from the air the time you leave it going for might be quite lengthy,to get more of a precise answer you might want to carry out a few titrations. On another note the dehydration of sugar with the aid of sulphuric acid if a definite indication that it absorbs more than 2 molecules of sulphuric per molecule sulphuric.

[Grapes Of Wraith]

quote by Rbick:

"Now as for the role of Sulfuric Acid: As mentioned earlier, the Sulfuric is used to absorb water from the resulting nitration and act as a catalyst, driving the reaction. Unless of course if you are using a nitration salt, in which case the Sulfuric is also used to make HNO3 through the reaction with the nitrating salt. Sulfuric Acid is not always needed in some reactions. For instance, RDX and PETN can use 95% or higher HNO3 alone. What happens when the Sulfuric Acid mixes with the water is as follows:

H2SO4 + H2O --> H3O+ + SO4 -

This creates a positively charged Hydronium ion and a negatively charged Sulfate ion. The two bond to form Sulfuric Acid Hydrate, or H2SO4*H2O. This is how Sulfuric Acid absorbs the water. If you can, visualize the Water and Sulfuric Acid “sharing” a Hydrogen atom. Sulfuric acid hydrate can be turned into steam from the exothermic reaction with water, which is corrosive and dangerous. Remember, add acid to water, not water to acid ."

This sounds right to me. but does that mean that 1 molecule of sulphuric only absorbs one water molecule?

[Rbick]

I didn't put accurate numbers for the reason that I'm not sure how many molecules of water 1 mol of Sulfuric Acid absorbs. I just know it is used for dehydration (among other things), and attracts water strongly enough to be considered hygroscopic.

It is probably more than 1, considering Sulfuric Acid is composed of a positive H ion and a negative Bisulfate ion. Or H+ and HSO4-. Or I guess you could say 2 positive H ions and one sulfate ion with a -2 charge. This makes the molecule itself electrically neutral, as things in nature tend to move towards more stability (entropy in action!), but the components hold the charge regardless. Along with the above reaction, which was discussed just a few posts eariler in this thread, the positively charged H ion(s) may attract the negatively polar Oxygen of the water molecule and the negativley charged Bisulfate would probably attract the positivley polar Hydrogen in other molecules of water. The above explains how most ionic compounds become hydrates. I had to bust out the organic chemistry text book for this... :D

In case you're wondering, polarity (http://http://en.wikipedia.org/wiki/Chemical_polarity) of a molecule depends on the electronegativity (http://http://en.wikipedia.org/wiki/Electronegativity) of an element. This is determined by the elements electron affinity, or how easily the element will give away or gain an electron. So when two mols of Hydrogen Bond with the one mol of Oxygen, the two elements' electronegativity effect the polarity of the molecule. So, since Hydrogen has a very low level of electronegativity, and Oxygens is substancially higher (the further up and right you go on the periodic table, the more electronegative elements become, Flourine being the most), the electrons shared in the molecule will be more attracted to, or "spend more time" around the Oxygen Nucleus. This will cause the side of the molecule with the oxygen atom to be more negativley charged (electrons are negativley charged particles), and are therefore attracted to the H ion of the Sulfuric Acid. The opposite is true of the H atoms of the water, which will be more attracted to a negative charge. When enough water has bonded to the molecule, it will dissolve in the water, becoming a solution. I think part of the purpose of the Sulfuric Acid in a nitration reaction is to have all the water absorbed and have enough Acid to not fully be dissolved by the water. This is a little off topic of NC, but it is applicable to the reaction needed to make it. Hope this helps the understanding of it.

How many it would bond with, I'm not sure. Could any body verify this or correct me if I'm wrong?

[megalomania]

If you are going to be pedantic, spell electronegativity right... :) Polarity is not just about electronegativity, carbon is only slightly less electronegative than oxygen, yet simple alkanes are not polar molecules. Water is polar because of its lone pair of electrons, the molecule is no longer linear which contributes to a dipole. Even fluorine containing molecules can be non-polar if in pairs because the effects of one cancel out the other.

You should also know that acidic species form H3O+, and solvation effects are a very complicated gridwork in solution as water can bond to other waters or species in the water.

[LibertyOrDeath]

Not being anything close to a chemist myself, I just did a quick Wikipedia check of how much water sulfuric acid will absorb (link (http://en.wikipedia.org/wiki/Sulfuric_acid#Reaction_with_water)).

It says that sulfuric acid reacts with water in two steps. First there's this:

H2SO4 + H2O → H3O+ + HSO4-

Then the bisulfate ion reacts with another water molecule:

HSO4- + H2O → H3O+ + SO42−

So, if we believe this, each mole of sulfuric ultimately "deals with" two moles of water. But then there's the solvation of each hydronium ion by multiple water molecules.

The above seems sensible, but maybe it's overly simplistic for what's being discussed here? I.e., in some reactions (possibly including NC) maybe the HSO4- ion initially produced will have a significant probability of reacting with something other than a water molecule, meaning that the H2SO4 will have killed off only one water molecule in that case? Pardon my naivety if this makes no sense.

[Rbick]

Thanks for the corrections Mega, I felt silly when I saw my mispelling. As far as being pedantic, well you know I'm always trying to impress you guys :D, along with trying to learn of course, since obviously I wasn't all too clear on the reaction.

But the polarity has little to do with the amount Sulfuric Acid bonds with water then? Its probably almost impossible to figure everything that happens exactly, but maybe the reaction between Sulfuric Acid and Water is as simple as they have it on wikipedia in perfect conditions? This reaction is something I don't know much about but have been very interested in for quite a while. Its fun to know how a reaction works along with actually performing it.

[nbk2000]

Experimentation would be in order.

Leave 1 mole of sulphuric acid exposed to the open air until it no longer gains weight, at which time you calculate the water absorbed, and that tells you what you want to know. :)

[megalomania]

Sounds like physical chemistry... EVIL! RUN AWAY!

[rangegal]

Has anybody ever heard of nitrating ping pong ball cellulose trinitrate into cellulose hexanitrate?

I'm just wondering because I'm going to try synthesizing NC for my first time tomorrow, but I can only make a bit because I only have a couple cotton balls left. Then I remembered I have a little jar of thick ping pong ball NC lacquer I mixed up the other day.

I figure it should work, since toluene is nitrated into the mono, then di, then trinitrate in separate steps. But other things in the ping pong balls (I read theres some camphor in there?) might get in the way of the nitration. Plus, as NBK says; chemistry isn't 1+1.

Either way I'm going to try it. I just wanted to see if anybody has heard of this before.

[rangegal]

Nitrating trinitrocellulose into hexanitrocellulose doesn't work. I don't know why I thought ping pong ball NC would dissolve in the acid mix.

I also learned when dealing with chemicals and using long sleeves for slight protection past your gloves, put rubber bands on your wrists to hold the sleeve to your skin. I was wiping spilt H2SO4 off the side of my graduated cylinder when I stupidly turned it upside down and a drop or two of acid left inside it must have fell down my sleeve. I didn't notice until I felt my flesh stinging and pulled up my sleeve to see what was up. A square half inch spot of flesh was red and puffing up along with tiny dots around it. I washed, neutralized and sterilized it before putting some scar ointment on it.

Perhaps wearing short sleeves is better anyway. I have spilt chemicals on my forearms before but always noticed quickly enough to wipe it and neutralize it before it caused any real damage.

[rangegal]

Sorry for posting 3 times in a row, but I just wanted to share a picture and video of my yield.
http://img512.imageshack.us/img512/212/dscf3664smallvh7li5.jpg

http://youtube.com/watch?v=IIfTLHX6qWM
Thats a small amount of fluffy NC burning. I don't know how much it weighed.
Is that fast burning? Or can it to be faster?

[Barnacles]

I know "SWIM" who puts their NC in a jar and use a hand blender to increase the surface area. Also he noted that NC burns extremely fast each time high quality or not if ignited with a cherry from a cigarrette or other smoking types.

EDIT as someone named bert mentioned in your video comments on youtube, that it appears to be lower quality. My question is how much would this effect VOD? the difference between the tri and hexa nitrates?

[Masonjar Chemist]

I also know "SWIM" who will never put anything other than inert compounds in his coffee grinder after he had an incedent with nitrocellulose detonating inside of his. Honestly this is a bad idea I would stop imediatly if you value your fingers.

[Barnacles]

Its never a large amount and always done remotely, so he says. I should've said that but to me its common sense. No offense intended.

EDIT the hand blender is about 2 feet long, and its blended in a plastic measuring cup that isnt sealed and never more than a gram or 2 is done ,so he says.

Could it be you did it in a sealed environment which allowed a DDT? any glass involved?

Thanks for the concern though! Will definately keep that in mind!

[Man Down Under]

It could be done safely if the NC was blended while suspended in water.

[Bert]

Phokion Naoum describes milling partially finished smokeless powder under water in a wheel mill to reduce it to particles small enough to be shot in rock bore holes. This was done during the period after WWI, when they were recycling military surplus into civilian explosives.

[peppovsky]

...I'm starting to think something is wrong with my chemicals (or is it with me?):

Today was my 5th unsuccessful (!!) try on Nitrocellulose synth. I used 100% cotton pad, 68% HNO3 and 98% H2SO4 . I mixed (drop wise) 3.5 ml of HNO3 with 6.5 ml of H2SO4 . I then added about 2 grams of cotton, and let it nitrate for 30 mins, while the temp kept at ~23 C. Then neutralized with saturated NaCO3 mixture, and two times water (the last batch of water was slightly basic when I tested it).

Now the thing is - as every time I tried making NC - the shit doesn't burn at all. I even tried igniting it with a torch - nothing. I dissolved it in acetone - and not all of the pad dissolved, just some it.

I really don't understand this. Should I let it sit in the mixture for more then 30 mins? Should I let it dry for a couple of days before trying to ignite it? should I rise the temp a bit while it's in the nitrate mixture?..


EDIT: I take that all back. Stupid me, never gave it a chance to dry thoroughly. After writing the post I took some and dried it in an oven for 210F (about 100C) for an hour. Then tested it. Now it burns fast, flashy and with that famous "woosh" sound. A lesson for all us noobs out there - let things dry before you give up :)

[Charles Owlen Picket]

...I'm starting to think something is wrong with my chemicals (or is it with me?):
Today was my 5th unsuccessful (!!) try on Nitrocellulose synth. I used 100% cotton pad, 68% HNO3 and 98% H2SO4 . I mixed (drop wise) 3.5 ml of HNO3 with 6.5 ml of H2SO4 . I then added about 2 grams of cotton, and let it nitrate for 30 mins, while the temp kept at ~23 C. Then neutralized with saturated.....


Your'e going too small scale! That's all. Everything is fine you just can't scale down NC synthesis to that point. Try working with at least a few hundred ml of acid and give it a try; you'll do fine! Nitrations are the Big Birtha of organic reactions and just need a heft and push to get them moving especially on cellulose ... :D ... You are going to NEED TO SPEND ACID on a nitration. That's a fact of life. :p

[peppovsky]

Thanks for answering, Charles.

Since my first success, I've slowly raised the scale each synth - even when it comes to the simplest nitrations I believe in caution. I know that I can theoretically scale it up as much as a factor of 10 or more, but before I start "manufacture" stuff in "bulk" (by "manufacture" and "bulk" I mean, of course, 100 grams NC MAX :p ), I need to see I can handle a reaction on a small scale... ;)

Yet, one thing remains unclear... when making the nitrating solution (0.65 parts [conc] H2SO4 and 0.35 parts [68%] HNO3, by volume), I first pour the H2SO4, then I stir (with a magnetic stirrer, 'course) and add HNO3 drop wise (actually 1/2 ml wise ;) ), on an ice bath, to avoid hot acid spills. This takes a lot of time.

My questions are:
1. Which is safer - Adding the HNO3 to H2SO4, or the other way around?
2. Is there any other safe way of mixing these acids, which is a faster one?

(EDIT: now that I think about it, since the HNO3 contains water, I should probably add the H2SO4 to the HNO3 and NOT the other way around - "Add acid to water", after all... am I right?)

[Charles Owlen Picket]

Realistically... acid to acid additions on the level we are talking about [with nitric and sulfuric] - the addition order means little.... Personally I would add the sulfuric to the nitric (for a somewhat quirky reason) but it's not big deal. You could make a point that there is more water in the nitric so that should dictate your choice; but I don't think it's a big deal....

If you can, keep the acids cold. You know that an exothermic reaction takes place when they are mixed; if they start off cold the level of heat produced is much less, even if mixed as fast as possible.

Put a pinch of Urea in the nitric; it keeps that delicious spicy nitric smell around awhile longer. You know.... "the smell of camel shit, RDX & cosmoline; that's the smell of the desert"

[peppovsky]

Of course, I always mix the acids on an ice bath, while monitoring the temp... The highest temp I've got to this day was 30C. Though, I haven't yet made a larger then 20 ml batch, and I guess a 100 ml batch or so will give off much more heat ;)

Yesterday, when making another NC batch, I've mixed the acids the other way around then I was used to (H2SO4 to HNO3 this time). Well, what can I say - the mixture got hotter then usual. I started on an ice bath, with temp at 10C, then it raised to 22-25C while adding the H2SO4, and it even gave out more acid vapors then usual - the other way around it tends to raise up to 20C, and give much less vapor. oh well.

[Charles Owlen Picket]

Just in point of our discussion, the sulfuric has greater density..... so perhaps that influences the exothermic dynamic.
Another thought -> I had some fantastic results in NC with toilet paper. I'm not kidding. It worked so well as to really be the first choice I make rather than cotton batting. I did try some totally natural cotton from a plant once but even after cleaning it - it still had some inconsistent results.
When people didn't burn their ping-pong balls 1st to SEE whether they were cellulose, some people attempted to nitrate them and wound up with plastic crap... :-] Geniuses! But those that did try to nitrate existing cellulose products often had pretty good results. The method of extracting NG & NC cleanly from double based smokeless powder is to use ethyl acetate and ethanol. I tried it and it really DOES work!

[peppovsky]

btw - How do you guys suggest to store the NC? I usually put it in a small plastic box, wet with lots of (distilled!) water, sealed so it won't get dry. Is there any better way to store it?..

[Charles Owlen Picket]

Storage of esters might include an anti-acid like a carbonate in solution. You could simplify by using baking soda @ 10% with your water.

Interrelated with this subject is the materials used in firearms propellants. Most people know that the standard of triple based smokeless is NitroGuanadine but actually there are HE's that are used as propellants as well! All these materials can be sourced out of the propellant if you have a desire to work at it.

[peppovsky]

It's ok, I have lots and lots of Na2CO3... ;) What about storing it with dry Ethanol?

[Charles Owlen Picket]

Alcohol is often preferred as it evaporates fast and [via refrigeration] can maintain itself as a low temp preservative. But you need a bit of water to dissolved the carbonate in as I believe that it does not go into solution well with alcohols.

Often in times past, kerosene was used as a preservative as it keep oxygen off the target material. But kerosene levels very tiny (almost imperceivable) amounts of residue after it evaporates.

[totenkov]

Yes kerosene is excellent for storing many HE. It is important to store acetylides and fulminates under kerosene because H2O will decompose them (those aren't the only salts).

I don't know about storing NC under Kerosene however. As Charles said, stay with fast evaporating liquids, Ketones and alcohols work best, when in doubt, use them before water.

[peppovsky]

Thanks for the advice. I have lots of n-Hexane around - I believe I will use it instead of kerosine (probably leaves less residue).

[Charles Owlen Picket]

I can comment on the residual materials left after kerosene evaporates.....it's not too bad and in some applications may be a positive. There are actually some positives to the use of same (& why it's been in use for some many decades).

Long ago when Hg Fulminate was actually made industrially kerosene was typically used in conjunction with it. When it would evaporate a tiny bit of residue was left. If the fulminate had any acidity left on it, it was often deposited in the residue. They they could be quickly flushed out with a fast bath of alcohol or ether & the fulminate was very neutral & acid free. Thus the preservative also sped production.

The advantage (speaking to the other side of this issue) of kerosene is that it allows virtually no air to ever come in contact with the product where as some thinner materials might. but most importantly, it can be frozen. This is why it may have been used so much with fulminate. It does not allow crystal reformation and in a deeply refrigerated environment, it does not allow for freezing to take place even at ridiculously low temps.

[Altroman]

The original idea of "Add the ACID to the Water and not vice-versa" was because mineral acids are denser than water, so the heat of hydration is released at the bottom of the container, where you have a mechanical "buffer" of a few inches or so of relatively pure water to protect your face from spattering acid (if you add water to acid, it forms a thin layer on top, then boils and spatters water and acid all over). When you mix two acids, add the denser acid to the less dense acid, so the same effect occurs.

[Cobalt.45]

The method of extracting NG & NC cleanly from double based smokeless powder is to use ethyl acetate and ethanol. I tried it and it really DOES work!

I would be interested in hearing more on the process if possible.

[Cobalt.45]

Turns out no voodoo is involved:). All I did was soak then stir/swirl a 5g quantity of Bullseye with denatured alcohol (100 parts ethyl to 10 parts methyl alcohol) over a period of an hour.

Decant the solvent into a drying dish, then evaporate the alcohol. What is left is a slightly yellow, viscous quantity of nitroglycerin. Because of the small amount of Bullseye that was used, the exact amount of NG obtained is not known. Theoretical yield would be only 2g. Judging by the amount that was obtained, this would be very close to that amount. It was eventually disposed of by burning.

What is known, is that when you soak a 1cm square piece of tissue with it (folded twice) then strike the tissue w/a hammer/anvil, the resulting blast will make you wish you had remembered ear plugs!

The powder grain was not physically effected The resulting powder after extracting the NG and drying looked very much as it had prior to extraction. It did seem to take a little longer to go into a NC lacquer solution when mixed w/acetone (which is what I was primarily after- "clean" NC from the Bullseye that I had on hand).

The constituents of Bullseye smokeless gun powder are as follows:

Nitrocellulose CASRN 9004-70-0
Nitroglycerin CASRN 55-63-0
Diphenylamine (DFA) CASRN 122-39-4
Ethyl centralite (EC) (diethyl diphenyl urea) CASRN 85-98-3
Rosin CASRN 8050-09-7
Polyester NJTSRN 800928-5003