zeppelin69
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House hold products to 100% HNO3?
I just had a revelation. I dreamed up a not so direct, but worth while synthesis for 100% white fuming nitric acid without the need for any expensive
distillation setup. In fact I am pretty sure you can just about buy everything needed at Wal-Mart.
The first step is to get DCM (dichloromethane). It is commonly used as a paint solvent, but seems that it is becoming phased out, as I cannot find it
anywhere. So, improvise by making your own. This can be done by synthesizing chloroform from acetone (or denatured alcohol, or methyl ethyl ketone)
and bleach (either Clorox, or even better calcium hypochlorite for pools). This mixture is distilled, and can be done with very improvised setups like
a glass coke bottle with rubber tubing coming out of it. The chloroform is then reacted with hydrochloric acid to yield dichloromethane. Which should
be redistilled using the same setup.
The nest step is to add a nitrate to sulfuric acid and chill the mixture in a freezer. Then add the DCM and carefully a few chunks of dry ice. this
should precipitate out pure anhydrous HNO3
I have not tested this yet so please let me know if there are any obvious reasons why this will not work. I will be trying this very soon and post in
detail exactly how it worked exact measurements of the chems etc.
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guy
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Whats the point of the DCM?
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zeppelin69
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Sorry, I was a little vague, the DCM acts as a solvent for the nitric acid. When the CO2 is added, it frezes out and can be seperated form the rest of
the mixture by filtering.
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not_important
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| Quote: | | The chloroform is then reacted with hydrochloric acid to yield dichloromethane. |
Care to elaborate on that reaction?
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zeppelin69
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That was the one step that I wasnt completely sure about. I know that iodoform will react with hydroiodic acid to give diiodomethane, but I have not
yet tried that with chloroform and HCl yet.
I belive it would go something like CHCl3 + HCl > CH2Cl2 +Cl2
Of course that is just a quick write up without all of the possible products. since the hydrochloric acid is dissolved in water I am sure there will
be imputities form the chlorine forming in water.
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12AX7
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That's because HI is a reducing agent (i.e., I2 is a poor oxidizer, under the conditions of this reaction).
More likely, you'll get it through reduction of CHCl3 (with what, Zn maybe?), or by chlorination of methyl species. For instance, you might do the
gaseous synthesis (over a heated catalyst): CH4 + 2 Cl2 = [CH3Cl + HCl] + Cl2 = CH2Cl2 + 2 HCl. Being a stepwise reaction, you'd get CHCl3 and CCl4
as impurities. You might instead start with methanol, chloridating it to methyl chloride, then chlorinating that by one step to CH2Cl2.
Tim
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not_important
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You might wish to look at http://srdata.nist.gov/solubility/sol_detail.asp?sys_ID=60_2... and http://www.springerlink.com/content/n0707q2571152526/, which document the solubility of HCl in CHCl3 and other solvents, with no mention of
reaction.
As Tim said, the reaction she no go. However, this may not be a problem as HNO3 is also somewhat soluble in chloroform. However, trichloromethane
freezes at -63 C, unlike dichloromethane which freezes at -97 or so.
There are a few other problems with your proposal. First, distilling chloroform through rubber or vinyl tubing may give you a surprise. Second,
| Quote: | | The nest step is to add a nitrate to sulfuric acid and chill the mixture in a freezer. Then add the DCM and carefully a few chunks of dry ice. this
should precipitate out pure anhydrous HNO3 |
is going to freeze the acid along with anything else, as you say
nothing about separating the organic solvent from the acid+salt mixture.
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Pyridinium
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Could always use a phase transfer catalyst such as a quaternary ammonium compound. You can get a dichlorocarbene intermediate (CCl2) by reacting
CHCl3 with base this way. I don't think you can get CH2Cl2 easily from the dichlorocarbene though. I can't find such a thing in any of the texts I
have. I think the reaction just goes all the way to formic acid.
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smuv
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I know a finely ground mixture of sodium bisulfate an sodium chloride produces anhydrous hydrogen chloride gas with moderate heating. It may also be
possible to do the same with sodium nitrate, this conceivably would yield anhydrous HNO3.
proposed reaction
NaNO3+NaHSO4 --> Na2SO4 + HNO3
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12AX7
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It is, but you get a large amount of NO2.
Nitric acid is typically distilled as H2SO4 + MNO3 = MHSO4 + HNO3, where M is an alkali metal ion. An excess of H2SO4 helps get the crud out of the
flask later.
Tim
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not_important
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| Quote: | Originally posted by smuv
I know a finely ground mixture of sodium bisulfate an sodium chloride produces anhydrous hydrogen chloride gas with moderate heating. It may also be
possible to do the same with sodium nitrate, this conceivably would yield anhydrous HNO3.
proposed reaction
NaNO3+NaHSO4 --> Na2SO4 + HNO3 |
As Tim said, you get a lot of NO2, which means water as well. Nitric acid is not that stable and must be treated gently, these temperatures are too
high.
I don't think that dichloromethane can be made from trichloromethane via carbene route, and even if it did form some the yields would be poor. Better
to try chloronating natural gas, with the receiver at 0 to 5 C so the chloromethane stays a gas and in the reaction zone while the polychloromethanes
condense out. As HNO3 is soluble in all of the chloromethanes a mixture of the di and tri chloromethanes is acceptable and will have less water
dissolved in it than straight CHCL3.
Dichloroethane might work, (CH2Cl)2 made from ethylene glycol, concentrated hydrochloric acid, and zinc chloride.
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12AX7
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Ya know what, a mixture of CHCl3 and CH2Cl2 would have a lower melting point than either one pure. Do mind the carcinogenicity of the products (up to
and including some amount of CCl4)!
Tim
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