Fuming Nitric Acid for HYPERGOLIC combustion.
This is theoretical, for discussion or consideration .
Molarity values are excluded
Warning: Dangerous Strong oxidizer: location, ventilation, and separation: KEEP AWAY FROM ORGANICS, SEE NOTES *1
I believe this would be a facile lab scale synthesis of a usable fuming Nitric acid. This method uses sodium bisulfate and sodium nitrate ( or KNO3) . I omitted the stoichiometry, though I believe a slight excess of the Bisulfate salt will drive the reaction to completion. I believe, the salts do not need to be anhydrous, but close to it. Some salt bound H2O is needed for the reaction to proceed.
A simple distillation apparatus
should high quality, meticulously cleaned and dry glass, with the fittings lubricated with concentrated H2SO4. *2. The dry mixture is heated until the acid distills
over.
The advantage to this would be not having
to deal with the exothermic reactions, risks, cost and need to redistill when using H2SO4. In addition, the product which
distill over is high yield and high concentration fuming nitric acid.
The density should be close to 1.5gr/cc, (the closer to 1.514gr/cc the more concentrated)
UV Light causes decomposition to NO2 with yellowing.
When doing this reaction, one must be careful, when handling the distillate of fuming HNO3 one should not wear
gloves as they burst in to flames on contact.*3
The fuming acid should be stored in clean, dry SHATTERPROOF amber glass to block UV.*4
Containers should not be filled more than 1/2,
to allow room for expansion a gas. The bottles must be carefully be vented monthly. *5
I'm have no knowledge about long term storage, but I think it prudent to use it quickly and not keep it around. In a fire proof, acid cabinet.*6
NOTES:
1.
Fuming Nitric acid is a strong oxidizer.
FIRE DANGER DUE TO HYPERGOLIC COMBUSTION ON CONTACT WITH MANY SUBSTANCES. ( eg lab gloves catch fire)
HNO3 emits dangerous corrosive vapors.
Keep combustable material away from
reaction areas.
Fire and/or explosion risk
from, but not limited to:
bases, reducing agents, metal powers,
alkalies, cyanides, sulfides, carbides and cellulose ( paper/wood).
This should only be done in a proper
fume hood, with fire suppression nearby and under supervision of a chemist
competent in laboratory arts and safely.
2. Ground glass joints must be lubricated with H2SO4. Concentrated sulfuric acid
will allow easy separation of ground glass. Standard ground glass greases could be oxidized and should be avoided due to the risk.
3. Latex and Nitrile gloves, will instantly combust in contact with HNO3, melt and stick to skin. I=E2=80™ve read that historically, in fact, no gloves were preferred to latex and nitrile (not endorsed just included to elucidate risk). Special gloves are, face shields and PPE are available. Small quantities may be dealt with in fume hood. Consult MSDS.
4.
UV light results in decomposition to NO2 with yellowing, darker on higher concentrations,
and could cause vapor pressures exceeding the container limit, or causing violent release on opening. Brown or Amber glass will block UV. Glass must should be shatterproof.
5. Glass bottles containing fuming HN03
must only be filled 1/2 way to allow and gases
to expand. In addition, they must carefully be vented at minimum monthly to prevent dangerous pressure build up.
6. Store in tightly closed bottle, in cool dark, dry place, and should be locked up and separate from other acids, alkalies, reducing agents and combustibles noted herein.
Consider a spill: would it instantly
ignite anything nearby, then mitigate risk.
See NFPA 43A, Code for the Storage of Liquid and Solid Oxidizers. Do not store above 23 =B0C (73.4 =B0F).
On Oct 15, 2020, at 10:15 AM, Yaritza Brinker <YBrinker**At_Symbol_Here**fele.com> wrote:
=EF=BB=BF
Laurie,
As you mentioned, this is a very good opportunity for education. I encourage you to use this opportunity to develop a short seminar series on hazard assessment and good experiment planning practices for your students. Small companies will
expect them to know who to do this on their own at the bachelor level.
Rather than calling out this particular case, you could use an experiment that is already being performed in the university as a case study or possibly an experiment that had been previously declined because it didn't pass hazard analysis.
You could even tie it back to the course work by doing theoretical calculations related to the safety of the experiment.
Take a cyanide titration for example. You could calculate the amount of cyanide gas released if the pH were to drop during the titration. The lethal respirable dose is available. You can use this information to determine the scale of the
experiment. You could even use your local ER response time to have the students think about the risk to human life if the experiment were to go seriously wrong.
Good Luck!
Yaritza Brinker
260.827.5402
From: ACS Division of Chemical Health and Safety <DCHAS-L**At_Symbol_Here**Princeton.EDU>
On Behalf Of Laurie Yoder
Sent: Wednesday, October 14, 2020 10:12 AM
To: DCHAS-L**At_Symbol_Here**Princeton.EDU
Subject: [DCHAS-L] nitric acid distillation
We have a senior chem student who has proposed making fuming nitric acid by reaction of fertilizer and concentrated sulfuric acid.. (wants to make rocket fuel because this is what they do on youtube...) After my first "no way on earth are
you going to do this!" they looked up some safety information and sent me the "proposal", copied below. This is a highly motivated student who loves chemistry and legitimately wants to learn and try new things so I hate to shut them down without taking the
opportunity for education. My problem is that everything about this looks high-risk, and I need some help to sort it out to best communicate what the concerns are, other than "you're going to injure yourself and damage the property."
My question for the group is what do you see as the top risks here and what would someone (in theory) need to do to mitigate them? I'm thinking (hoping!) it should become obvious to the student why we can't manage it here.
This is from the student:
"The reaction vessel will be a round bottom flask with a heater from there the gaseous nitric acid will run through a still cooled with ice water and covered with aluminum foil to minimize the breakdown of nitric acid into NO2 due to UV light. The product will
be collected in another round bottom flask and the excess NO2 and uncondensed Nitric acid will be bubbled through a water trap (we shouldn't use rubber tubing here).
"Products- Sodium Sulphate is a common fertilizer just like sodium nitrate the last of the acid in the reaction chamber can be neutralized and the waste can be easily disposed of as solid waste or mixed into the compost pile.
"Fuming Nitric Acid- This is the product we are interested in collecting. It will be used by XXX as the oxidizing agent in a model rocket. Fuming Nitric acid quickly destroys Nitrile gloves, setting them alight and melting them. For this reason an alternative
is necessary. Vinyl gloves deform a bit but do not melt or burn on contact with Fuming Nitric acid. Therefore obtaining Vinyl gloves and a Vinyl smock could also be a productive option. That said, direct skin contact with fuming Nitric acid is not as damaging
to the skin as solutions containing more water. As long as it is promptly removed working without gloves would potentially be a viable option. All work will take place in the hood because gaseous nitric acid and NO2 are continuously released. Once the Fuming
Nitric Acid is isolated it can be stored indefinitely in an amber glass container with a teflon sealed lid.
"Nitric acid from water trap- This product's density can be measured to determine its concentration. Then it can be stored in glass for use in other experiments.
"NO2 gas- We will do our best to minimize the production of this side product. Nitric acid breaks down into NO2 faster at high temperature and with more light. We will minimize the necessary temperature in the reaction pot, and ice the condensing regions and
product. All the glassware connections will be greased using the same sulfuric acid in the reaction pot which would be a good reason to wear vinyl gloves. This will seal the reaction with the overpressure continuously bubbling into the trap where more of
the gas can condense and the extra NO2 will be pumped out of the hood where the entire synthesis will occur.
"Additional considerations
Limiting personnel access- Because the Chemical prep room is the only hood which is off limits to most students during the day it would be the ideal location for this synthesis. 2 people will monitor the reaction at all times and eyewashes and a shower are
readily available. There is a designated fire extinguisher on hand and the labspace is not used too much so it can be cleaned up and sorted to meet our needs.
Eye protection- Eye protection will be worn at all times
"YouTube Sources
https://www.youtube.com/watch?v=QmCdrDLyNXQ&t=502s
https://www.youtube.com/watch?v=aUzMms62hKw
"Duke OESO Guidelines for Safe Use of
NITRIC ACID...[lots more copied and pasted stuff from internet...]
--
Laurie M. Yoder, PhD
Assistant Professor of Chemistry and Chemical Hygiene OfficerEastern Mennonite University
540.432.4420
--- For more information about the DCHAS-L e-mail list, contact the Divisional membership chair at
membership**At_Symbol_Here**dchas.org Follow us on Twitter **At_Symbol_Here**acsdchas
Electronic
Transmission Confidentiality Notice
The information
contained in this electronic transmission is private, confidential, the property of the sender, and intended for the use of the recipient(s),
only.. If you are not the addressee, any disclosure, copying, distribution or use of this information for any purpose is strictly
prohibited. If you have received this information in error, please notify the sender,
YBrinker**At_Symbol_Here**fele.com, immediately by e-mail and then delete this message. Thank you.
[FE.EN.1]
---
For more information about the DCHAS-L e-mail list, contact the Divisional membership chair at
membership**At_Symbol_Here**dchas.org
Follow us on Twitter **At_Symbol_Here**acsdchas
Previous post | Top of Page | Next post
