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Author: Subject: Determining percentage of nitration of nitrocellulose
Quince
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[*] posted on 22-2-2005 at 18:30
Determining percentage of nitration of nitrocellulose


How can it be done?

Also, in blasting gelatin, does it make much of a difference whether low (11%) or high (13%) nitration nitrocellulose is used, given the small proportion of 8% vs the nitroglycerin?

[Edited on 23-2-2005 by Quince]




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[*] posted on 22-2-2005 at 21:20


Fully nitrated cellulose hexanitrate (guncotton) is not soluble in trinitroglycerin while the lower nitrates are completely soluble in NG. There are other methods of dertermining the nitrogen percent but I doubt you have the accessability or the means to do so:P

And yes the amount of NC to NG will affect the power and performance of the blasting gelatin.

Quincy, if you bothered to read the books I sent you, you would not have to ask stupid questions or start stupid threads that are closed, much like I'm sure this one will soon be.
;)

[Edited on 23-2-2005 by Joeychemist]
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Quince
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[*] posted on 22-2-2005 at 21:59


I'm not asking about the amount of NC to NG, but the amount of nitration of the NC. It's pretty clear from the way I worded it. Does the 11% or 13% nitration of the NC make a significant difference when used in the gelatin, assuming the NC:NG ratio is the same in either case?

[Edited on 23-2-2005 by Quince]




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[*] posted on 22-2-2005 at 22:10


Of course it will make a difference, it will make a difference in nitrogen content and it will make a *slight* difference in power, but other than that, not really no.
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[*] posted on 8-7-2005 at 20:07


I am currently working on learning ASTM D4795 "determination of nitrogen content in soluble nitrocellulose, alternate method" for my purposes.

It's basically a potentiometric titration of a concentrated H2SO4/nitrocellulose solution with a ferrous sulfate/H2SO4 solution.

Calculation: N=(C x F)/D
Where: N = nitrogen content of sample.
C = FeSO4 to titrate the specimen, ml.
F = Equivalence factor.
D = Weight of sample in grams.

My problem is that the standard describes the making of the FeSo4 solution as follows:
--------
Dissolve 350 grams of ferrous sulfate crystals in 1000ml of distilled water.
Add 1000ml of 1+1 H2SO4 solution.
--------
For some reason I can't seem to find out what the heck a 1+1 H2SO4 solution is.

I have fabricated a set of electrodes from a copper wire that shrouded in glass and a platinum tipped sealed glass tube with a copper core.
I have tested them using an analog ohm meter and so far everything is ready for my first test run. I will post the pictures and results as soon as I have them. This method should be fairly easy and cheap for anyone to use. It sure should be easier and safer then the old lunge nitrometer.

[Edited on 8-28-2006 by Polverone]
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Lambda
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[*] posted on 9-7-2005 at 05:04


Dear ordenblitz, apparently they mean that you have to add concentrated sulphuric acid (98%) to 500 ml of distilled water to a volume of 1000 ml. Then you have to mix this with 1000 ml of the Fe(SO4)2 solution to 2000 ml.

REMARK: Allways add concentrated acid very slowly to water, and never the other way round. Alfred Bernhard Nobel applied for a patent on this procedure. One of his ~500 patents.
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ordenblitz
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[*] posted on 9-7-2005 at 05:11


That was my first thought, but usually it's written, 1:1 or 1-1 or 1/1 or 50% soln.

I have never seen it stated 1+1

thus my confusion
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[*] posted on 9-7-2005 at 11:20


I agree with you ordenblitz, it's a very unusual way of notation. I find it even more confusing, seeing that they put so much emphesis on rules, problem approach, common agreements with respect to purity etc..
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[*] posted on 5-8-2006 at 08:26


I have been asked about my progress with this via u2u, but I will answer here.

Although I have learned much, I also have been confounded by this seemingly simple test. Lacking a potentiometric titrator it is very difficult to determine the endpoint with any certainty. Also I have had absolutely no formal training on this type of titration. From what I have learned the endpoint is the place of 'greatest change'. I have considered plotting this according to the conductivity in relation to the titrant added but am thinking that could take many hours, and all I had was a PH meter. There is a color change at or near the endpoint but it happens in stages and in such a way that isn't very indicative. I have had varying results but at this point, I can only tell by visual change at best to within 1/2% on actual nitrogen content when testing known NC samples and testing on potassium nitrate.

SAM4CH asked:
"What is the procedure of Standardization ferrous sulfate solution using KNO3? and what is the suitable indicator for this!!?"

You make the titrant solution and then use KNO3 to standardize it since the nitrate contains a known amount of nitrogen. You then do the titration on it and assuming you are able to accurately determine the endpoint, you then use that information to tweak your calculations. "F" represents any deviation from theoretical in the titrant due to variances in the chemicals you used to prepare it.

F=(Ax13.833)/B
where:
13.833 is the known nitrogen content of PN
A = weight of the nitrate
B = amount of titrant used to reach equivalency

You then do the same titration procedure on your nitrocellulose sample using the same titrant, H2SO4 etc. to the endpoint. Take the data and plug it into the final formula.

N = (CxF)/D
where:
N = nitrogen content
D = weight of the nitrocellulose
C = amount of titrant used to reach equivalency
F = Equivalence factor from above

My problem was accurately determining the endpoint. If you don't have the proper equipment it is difficult to do. I continue work on this method as I have acquired some new equipment. When I find the proper electrodes for the meter I bought, I will try again.

Lastly, one could practice on KNO3 ad nauseum, until you were good at visually determining the endpoint. This at least would generate numbers decent enough for most people. Don't forget to stir the sample vigorously when adding titrant and use an accurate buret.

[Edited on 5-8-2006 by ordenblitz]

[Edited on 5-8-2006 by ordenblitz]

[Edited on 5-8-2006 by ordenblitz]
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[*] posted on 5-8-2006 at 14:00


If I use traditional buret and use ORP meter, can I reach a good accuracy and precision!?
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ordenblitz
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[*] posted on 8-8-2006 at 17:11


One way to find out... do the test over and over on a known sample and see what the deviation is.
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[*] posted on 10-8-2006 at 00:30


So again, what mix of acids/water/cellulose gives the best product for gelling NG?



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[*] posted on 10-8-2006 at 03:52
ISE for Nitrogen content


Is Ion Selective Electrode can be used for measuring nitrogen content of nitrocellulose as nitrate?
Is cellulose nitrate release nitrate ions when dissolve in 98%H2SO4 ..and then can I measure nitrate value using ISE meter?

What about Ethyl acetate as a solvent for nitrocellulose in its all grades "nitrogen values", is it better than acetone?

[Edited on 12-8-2006 by SAM4CH]
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[*] posted on 22-8-2006 at 11:17


I have developped an approximation formula but I don't know if it gives good results or not... With my own nitrocellulose I found generaly about 12.7%~13.1%.

N% = (1 - M1/M2)*42/135

where M1 is the mass of cellulose before reaction and M2 is the mass of the final product. Of course, they must be very dry or you will weight a lot of water and get a higher nitrogen percent.
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[*] posted on 22-8-2006 at 14:07


The NC used to gel NG is about 12% right? What initial cellulose and acids ratios are used for that?



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[*] posted on 23-8-2006 at 08:01


That cannot be said for sure, as a lot of different factors are important here, such as the quality and pretreatment of the cellulose.
As pretreatment, cotton is boiled in 2-4% NaOH solution for a few hours (and then of course washed and dried). This removes resins and cell plasma residues. It HUGELY improves the quality, stability and nitration degree of NC when the cotton is treated like that, I tried this out.

With nitration mixes of H2SO4 and HNO3, the maximum attainable nitration degree is around 13,4% (using oleum and fuming HNO3).

The theoretical nitration degree of 14,4% can only be reached with special nitration mixes containing no H2SO4.
One of them is a solution of P2O5 in anhydrous HNO3, and the other one is a mix of 1 part glacial acetic acid, 1 part acetic anhydride and 2 parts anhydrous HNO3.
The last one is dangerous since it slowly forms the extremely toxic tetranitromethane. After nitration (30min) and removal of the NC the mix must immediately be destroyed by addition of water.




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Quince
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[*] posted on 23-8-2006 at 14:40


Well as I said I'm not interested in high nitration. Highly nitrated cellulose does not dissolve in NG. That's why I asked what the ratio of acids and water content is appropriate for giving the moderate nitration making NC useful for NG gelling.



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[*] posted on 18-9-2006 at 10:35


I got ORP electrode but how can I reach accurate result without standard NC sample?!!
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[*] posted on 19-9-2006 at 11:26


Quote:
Originally posted by Quince
Well as I said I'm not interested in high nitration. Highly nitrated cellulose does not dissolve in NG. That's why I asked what the ratio of acids and water content is appropriate for giving the moderate nitration making NC useful for NG gelling.


Check Federoff volume 2 C102 where examples are given for methods and ratios to produce cellulose nitrate of 12.6 and 13.4% nitrogen.

It shouldnt be too difficult to extrapolate these figures to get that ideal 12% nitrogen content for collodoin and gelling nitrate esters ::D
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Quince
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[*] posted on 19-9-2006 at 11:31


Quote:
Originally posted by Deceitful_Frank
Federoff volume 2 C102

Can you give a proper citation? I'm not a chemist, so I'm not familiar with this reference. Is there an electronic version available? As for extrapolation, if only two points are given, I can only do linear extrapolation; how do I know that this is valid?




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[*] posted on 19-9-2006 at 12:10


I'm beginning to draw the conclusion that you really are hard work Quince!

Of course there is an electronic version available and if you want the information then you will find it for yourself.

I've given you as much help and have gone to as much trouble as I am willing. Who cares if its linear or logarithmic... does it really fucking matter?

Just find the page in the book that I suggested, use some initiative and make an educated guess!

Dear oh dear ::D
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[*] posted on 19-9-2006 at 14:51


SAM4CH....
You use KNO3 as your standard. It contains 13.853% nitrogen and behaves as NC does in H2SO4 for the purposes of this titration. Remember to dry it at ~110ยบ for a few hours before your tests.
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Quince
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[*] posted on 19-9-2006 at 17:43


Well I don't know which book that is, you never gave a title!



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Quince
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[*] posted on 25-9-2006 at 20:33


I'm still waiting to hear what the title is.



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[*] posted on 26-9-2006 at 00:56


You really are a fucking idiot, and if you think that I am the only forum member that shares this opinion then I pity you.
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