Sciencemadness Discussion Board - Ratio H2SO4-NH4NO3 compared to H2SO4-HNO3

Ratio H2SO4-NH4NO3 compared to H2SO4-HNO3

Atom - 11-2-2005 at 03:21

Lets say I need, in total, a 238 ml acid mixture from 100 ml 98>% HNO3 and 138 ml H2SO4. But I dont have any HNO3 can I use 167 g NH4NO3 instead with 138 ml H2SO4?

Quince - 11-2-2005 at 04:09

I want to add a question to this: would the ammonium bisulfate in the solution be a problem when this is used for nitrating, say cellulose or glycerin?

For example, the cotton I nitrated turned into a not-clear, slightly milky liquid when dissolved in acetone, so I'm guessing much of the impurity was left in the final product. Can this be a problem?

Atom - 11-2-2005 at 05:12

Yes, but if you wash it properly I thought the ammoniumbisulfate will be washed away.

Edit : I calculated how much I need and its about 160 grams of NH4NO3 and 138 ml H2SO4, does this seem right to you guys?

[Edited on 11-2-2005 by Atom]

neutrino - 11-2-2005 at 14:41

The mix should work for nitrations, but the large quantity of stray metal ions left behind by this method (NH4+ imitates K+

decrease yields considerably.

Quince - 11-2-2005 at 23:43

I'm going to put together a vacuum distillation setup, and I'm waiting for glassware from eBay. I read somewhere that flat-bottomed flasks should not be used for vacuum. But then how can I heat a round flask on a hot plate? An oil bath is a problem due to the smell. Can I use a plumbing torch, or would that be too hot?

rikkitikkitavi - 12-2-2005 at 02:41

If you use vacuum distillation of HNO3 the boiling point will be far less than 100 C, which makes the use of water as a heating media possible. In a ordinary metal pot or something similar

however, beware of the buyoance force of the flask. Also, use a protective shield in case of glass breakage (both to protect from glass pieces flying around and acid splashing when in contact with the water)

normally, in the lab heating mantles are used for this purpose but they are quite expensive, and spillage might cause electrical shock. Using a earth fault breaker is notoriously difficult with heating mantles , since they always trip due to bad insulation...

neutrino - 12-2-2005 at 06:33

The reason they use baths in this situation is to spread the heat evenly, lessening the heat stress at any one point. The glass is under enough stress as it is from the vacuum, anything greater would be a big problem. The standard rule of thumb is that the temperature difference between your bath and the inside of your flask should not be more than 30*C, especially under a vacuum. IIRC, a decent vacuum will get your acid boiling at around 40*C, meaning you could easily use a water bath (with a small amount of wax on top to prevent evaporation).

vulture - 12-2-2005 at 12:58

You people need to learn using theory instead of recipes to calculate your ratios...Furthermore, quince, don't sidestep this thread because yours was closed.

When using HNO3, NO2+ is directly formed in the reaction between H2SO4 and HNO3:

HNO3 + 2H2SO4 ---> NO2+ + H3O+ + 2HSO4-

With NH4NO3 you first have to form the nitric acid, after which the above reaction can take place.

Quince - 12-2-2005 at 23:40

vulture, there's nothing specific to explosives in this post. Distillation is used throughout chemistry. I don't see why asking about how to heat anything in a flask is against forum rules.

[Edited on 13-2-2005 by Quince]

vulture - 13-2-2005 at 11:30

Quote:

would the ammonium bisulfate in the solution be a problem when this is used for nitrating, say cellulose or glycerin?

Quote:

vulture, there's nothing specific to explosives in this post.

I don't think this needs any additional comment...

Quince - 14-2-2005 at 07:46

WTF?! I was talking about MY SECOND POST HERE:

Quote:

I'm going to put together a vacuum distillation setup, and I'm waiting for glassware from eBay. I read somewhere that flat-bottomed flasks should not be used for vacuum. But then how can I heat a round flask on a hot plate? An oil bath is a problem due to the smell. Can I use a plumbing torch, or would that be too hot?

I'm still waiting for an answer.

Atom - 14-2-2005 at 09:46

Depends on the manufacturer of the equipement. And if its borosilicate or Duran etc..

Normal equipement wouldn't stand up to the heat but glass of the the kind I just mentioned can.

[Edited on 14-2-2005 by Atom]

vulture - 14-2-2005 at 12:02

Quince, you better drop your cocky attitude ASAP.

Quote:

WTF?! I was talking about MY SECOND POST HERE:

Which is competely offtopic ALSO. So STFU and search before you're gonna be sorry.

Magius - 14-3-2005 at 09:13

I'd hate to bring up an old topic, but if there is a good way to have good yeild nitrations that don't require 98% HNO3, that would be excellent, as some of us don't have(and can't obtain) good distillation glassware.

As its been stated before, the addition of a nitrate will lower the yeild significantly becuase of the positive ion from the salt.
But think of this; Many Alkaline-earth metals drop out of solution when they combine with the sulfate ion. So this begs the question, would adding such a nitrate(like easily obtainable Ca(NO3)2) to concentrated Sulfuric Acid in the correct proportions create the same nitrate bath as the mixture of concentrated nitric and concentrated Sulfuric?

Atom - 14-3-2005 at 12:17

Yeah, but the problem is that most people can't weigh the exact amount needed of fluids and nitrate salts accurate, so that you'll have 98>% HNO3.

neutrino - 14-3-2005 at 13:56

This has been thoroughly discussed at RS. In a nutshell, it won’t work because the sulfate layer prevents more nitrate from reacting. You might be able to get some yield, but this would almost certainly not be worth it. You could always improve this by grinding the stuff to a fine dust, but calcium nitrate (the most common one you’ll find) is extremely hydroscopic.