Micah 5.56
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Gun cotton from 50% nitric acid?
Hello,
I would like to make some gun cotton but where I live (Colombia) I have only been able to source 50% nitric acid. I have 500ml of this plus 500ml of
98% sulfuric acid. From researching, it seems that a higher concentration of nitric acid can be distilled, but I also have not been able to locate a
distillation set here. I will be making a trip back to the states at the end of the month, and will be bringing back some glassware, a hot plate and
some other lab items so I could possibly bring back a distillation set as well.
However to be honest, the toxic fumes of RFNA or WFNA kind of scare me. I looked into buying a respirator but in searching for the proper filters was
told that only a supplied air respirator system would be sufficient protection from fuming nitric acid. The cheapest set up like that I found (and
maybe getting the cheapest option isn't a good idea when dealing with your health/life?) was around $1,000. It also may be a problem explaining to
Colombian customs why I need such equipment.
So, what looked to be a fun, easy experiment is now looking like more trouble than it's worth. Anyways what I was wondering was, has anyone made gun
cotton from 50% nitric acid? And does the stoichiometry need to be adjusted, or maybe longer reaction time?
Also, after you guys have used nitric or sulfuric acid in a beaker, how do you clean it out? Is baking soda and water to neutralize and then soap and
water ok or is there another, better way? Sorry if that's a really basic question but I'm just starting out and would like to not make any major
mistakes right out of the gate.
I'm tempted to just go ahead and try the synthesis with the chemicals I have, but glassware is kind of expensive here so I'm trying to hold out until
I go back to the states and buy some more beakers there. Funny enough glassware is expensive here but the chemicals are pretty cheap. 500ml of
sulfuric acid cost around $2.70 and 500ml of 50% nitric acid only cost around .70 cents!
Except acetone. I was quoted $150,000 pesos (around $80 USD) for a liter of acetone! Not sure why that's so expensive here.
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amazingchemistry
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I don't think the fumes would be much of a problem if you do the distillation outside. I'd suggest a fume hood, but those are very expensive (probably
worth 10 respirators  ). You could consider scaling down your setup. Microscale
glassware, while more expensive in the short run, saves money on reagents and fosters good lab technique. In addition, any fumes generated would be
much easier to deal with. Perhaps even an "improvised" fume hood, of the sort you make from a water aspirator and a funnel, would work with such a
setup. On the cleaning question my old ochem lab manual advises simple neutralization with baking soda before washing down the drain after a nitration
experiment. Heck, it even uses reasonably dilute nitric acid to clean stubborn glassware. Given that, I think that if you neutralize your acids and
rinse with plenty of water you should be fine.
PS: Two more benefits of a microscale setup include reduction of waste and the setup being harder to find and confiscate by customs
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Micah 5.56
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I might try googling homemade fume hoods at some point in the future, but really it's a bit more than I care to bite off right now. My apartment has a
decent terrace where I can do some work outside, however there's a police substation right in front of my building and having a fume hood on my
terrace would attract more attention than I would like (and I would like no attention at all).
The microscale idea sounds interesting, I'll check into that. Still hoping someone will come along and say they've used 50% HNO3 to make gun cotton
and that it works as good as 70%. Probably shouldn't hold my breath though. I think I'm gonna give it a try here in the next few days and find out for
myself the truth of the matter.
Thanks for the info on clean up. I've seen lots of videos and read lots of posts but no one ever mentions the clean up aspect. I guess probably
because it's so basic huh? I'm gonna buy The Organic Chem Lab Survival Manual: A Student's Guide to Techniques. It sounds like a good primer that
should hopefully get me pointed in the right direction.
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Oscilllator
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Theres no chance at all 50% nitric acid will work aswell as 70%, simply because the more water you have the lower your yeild. You could try adding
large amounts of sulfuric acid (maybe 1 part nitric to like 5 parts sulfuric?) to try and get rid of the water, but that would probably just be a
waste of acid.
If it were me, I would try and find a nitrate salt (preferably potassium nitrate) and do a distillation with the sulfuric acid to make RFNA. The fumes
wont be a problem if you do the experiment outside. Dont get a micro-scale glassware setup, there boring.
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Simbani
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A ratio of 1:5 is just plain nonsense IMHO. The procedure works well even with 53% HNO3, I used a ratio of 1:2 HNO3 to H2SO4 by volume when I had no
stronger acid available. The cellulose should be added at 0-5°C and the reaction time should not be longer than 3-4 hours, longer reaction time is
contraproductive. Wash well with water and then in Na2CO3 solution, if a acid-free product is wanted you can boil it in ammonia water for a few hours
because NH3 can more easily go into the nitrated cotton-fibers.
There will always be residual acid in your NC, recrystallizing is the only way to neutralise it completely.
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chemcam
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Quote: Originally posted by Oscilllator  | | Theres no chance at all 50% nitric acid will work aswell as 70%, simply because the more water you have the lower your yeild. |
That is definitely incorrect I have made tons of nitrocellulose by using 70%, and lower is possible as long as you add enough H2SO4 to deal with the
water. I am certain 50% would work it may take longer and you will need more sulfuric obviously.
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Micah 5.56
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| Quote: Originally posted by Simbani | A ratio of 1:5 is just plain nonsense IMHO. The procedure works well even with 53% HNO3, I used a ratio of 1:2 HNO3 to H2SO4 by volume when I had no
stronger acid available. The cellulose should be added at 0-5°C and the reaction time should not be longer than 3-4 hours, longer reaction time is
contraproductive. Wash well with water and then in Na2CO3 solution, if a acid-free product is wanted you can boil it in ammonia water for a few hours
because NH3 can more easily go into the nitrated cotton-fibers.
There will always be residual acid in your NC, recrystallizing is the only way to neutralise it completely. |
Thanks for the input. I have heard of 52% HNO3 working as well. Hopefully the extra 2-3%, or lack of rather, is not a deal breaker.
| Quote: Originally posted by chemcam | | Quote: Originally posted by Oscilllator | | Theres no chance at all 50% nitric acid will work aswell as 70%, simply because the more water you have the lower your yeild. |
That is definitely incorrect I have made tons of nitrocellulose by using 70%, and lower is possible as long as you add enough H2SO4 to deal with the
water. I am certain 50% would work it may take longer and you will need more sulfuric obviously.
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Ok I'm starting to feel like this might work. Need to get my hands on some more glass so I can find out for sure. You guys in the states are really
lucky with the easy availability of chemicals. 69%-70% HNO3 all over the place, on ebay, amazon, etc. not to mention stuff like KNO3, sulfur,
percholrates/chlorates etc etc. All that stuff is tightly controlled here. 
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macckone
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Be careful.
Export of chemicals or laboratory equipment to columbia is restricted by DEA regulations.
The reason acetone is expensive in columbia is because it is used in illicit industries endemic in that country. The DEA is very strict on enforcing
its export regulations.
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