| Pages:
1
..
12
13
14 |
AJKOER
Radically Dubious
Posts: 3012
Registered: 7-5-2011
Member Is Offline
Mood: No Mood
|
|
Reagent Friendly Path: Just a small starting amount of H2O2, aqueous NH3, Cu, air and some NaOH to maintain alkaline pH, and as this is an
electrochemical cell, a small touch of a good stating electrolyte like sea salt, all resulting in NaNO2.
It is well known that the electrochemical dissolving of Cu with aqueous NH3 in the presence of air creates a side product of NH4NO2, which apparently,
at one point (I suspect removal of ammonia resulting in a lower pH), creates a massive sudden N2 release per the decomposition of formed NH4NO2 (so,
do employ a wide mouth and tall reaction vessel and still, at times, I get a spillage event).
See my prior comments on this event and details on the reaction previously posted here https://www.sciencemadness.org/whisper/viewthread.php?tid=18... which also includes another reference on the electrolysis route to nitrite (not a
galvanic cell).
Now, adding NaOH likely averts this NH4NO2 decomposition reaction forming the targeted NaNO2.
Also, the reaction with ammonia is depicted as proceeding both with H2O2 and O2 exposure along I suspect, it is not O2, but perhaps superoxide formed
from solvated electrons (e- per the electrochemically cell) acting on oxygen (O2 + e- -> .O2-). Basis, quoting from a source at https://www.frontiersin.org/articles/10.3389/fmars.2016.0023... :
"Superoxide (O−2) also reacts with trace metals (Figure 1B) to produce H2O2; reactions with Cu(I) can proceed rapidly with rate constants (k) on the
order of 2 × 109 M−1 s−1 (Zafiriou et al., 1998), although [Cu(I)] is relatively low (~0.1 nM; Moffett and Zika, 1988)."
which is my polite way of saying that a direct oxygen path may not be precisely correct.
[Edited on 16-7-2022 by AJKOER]
|
|
|
Antiswat
International Hazard
Posts: 1621
Registered: 12-12-2012
Location: Dysrope (aka europe)
Member Is Offline
Mood: dangerously practical
|
|
AJKROER
you mention formation of nitrite in the same reaction vessel as.. superoxide, and also using H2O2? nitrite reacts with oxygen to form nitrate
if this is a membrane cell it adds difficulty to the operation, though its very possible to make your own membrances with PVC glue and plastic cloth
would be cool if it was a viable electrochemical route for making nitrite
i would go with oswald if i had space to have such a thing going, simply dumping the gasses through water and then have them pumped through hydroxide
solution should do
the starch method is interesting, any mentions of what may be formed? nitrostarch is a thing..
im not quite sure of how one would gauge the quality of the gas mixture, amount of gas bubbles in second container after first water-scrub? im not
even sure if NOx from nitric acid is viable for this.
i employed my IPN method, i got 100mL of presumably mostly IPN
so i set up for short path distillation and ended up with a majestic.... 35 milliliters of IPN, from maybe 300mL 62% HNO3 - hmmmm, im not sure if this
is a good yield.
i did insert an airbubbler into my flask to counteract the ups and downs in temperature from my hotplate and the reaction- afaik nitrite isnt super
sensitive to oxygen, but maybe im wrong, maybe i turned my poor nitrite into nitrate like that. maybe i messed up on making the IPN itself?
regardless if one goes with the NOx method, its ideal to pump the gasses into KOH solution, then dumping it in freezer will crystallize the KNO3 and
youre left with mainly KNO2 - K2CO3 may also be used
how would one go about modifying the starch reaction, is the nitric acid dripped into solid starch, into starch solution, starch solution dripped in?
controlled heating?
|
|
|
AJKOER
Radically Dubious
Posts: 3012
Registered: 7-5-2011
Member Is Offline
Mood: No Mood
|
|
Correctly, there are claims of the direct action of oxygen gas on nitrite (and not superoxide) with NaNO2, as an example, a decomposition warning for
the dry salt (see https://nj.gov/health/eoh/rtkweb/documents/fs/2258.pdf ), to quote:
"away from AIR, LIGHT, and MOISTURE."
However, I suspect, this trilogy are hardly independent agents, as nitrites are noted as photocatalysts.
NO2- + Light (Blue) -> .NO2 + e-
And, the hydrolysis of .NO2 is a known path to nitrous and nitric acid:
.NO2 + .NO2 + H2O -> HNO2 + HNO3
Again the action of light on nitrous acid:
HONO + Light -> .HO + .NO
And, the action of a solvated electron on oxygen:
O2 + e-(aq) --> .O2- (the introduction of the superoxide radical anion in the presence of an oxygen source)
which can also be sourced in the present of a transition metal impurity, in the so-called metal auto-oxidation reaction with dissolved oxygen:
M -> M+ + e-
O2 (aq)+ e- --> .O2- (aq) (again with the formation of superoxide)
And, the action of superoxide on nitric oxide is a well known path to peroxynitrite and eventually nitrate:
.NO + .O2- -> ONOO
So, once the photo or a transition metal inducing electron presence ceases (not just air presence, for example), a nitrite product could be stable.
This is supported here in the copper, ammonia, O2/H2O2 reaction system with no citations of any ammonium nitrate creation.
Also, there is a source citing the presence of ammonium carbonate (see https://www.sciencemadness.org/whisper/viewthread.php?tid=14... ) fostering the dissolving of copper ore with water, ammonia and oxygen. This is
interesting as CO2/HCO3- appears to be a radical reaction promoter, to quote a source ("Radical production by hydrogen peroxide/bicarbonate and copper
uptake in mammalian cells: Modulation by Cu(II) complexes" at https://www.sciencedirect.com/science/article/pii/S016201341... ):
"It is well-known that the bicarbonate/carbon dioxide pair, the presence of which is important in maintaining physiological pH in extracellular body
fluids, can accelerate the transition metal ion-catalysed oxidation of various biotargets. Despite of its relevance, however, most of the mechanisms
that have been proposed to account for this important effect remain controversial [8], [9], [10], [11], [12], [13], [14], [15], [16], [17], [18],
[19], [20], [21]. On the other hand, it is accepted that the bicarbonate/carbon dioxide pair can increase peroxynitrite-mediated one-electron
oxidation and nitration via formation of the carbonate radical and nitrogen dioxide [22], [23].
So discounting possible underlying radical based reaction paths (aka, not just simply a direct elemental oxygen interaction) is not likely precisely
correct, in my opinion.
As further evidence of the actual possible complexity in systems involving dissolved (not gaseous) .NO see my sources cited relatedly in this SM
thread https://www.sciencemadness.org/whisper/viewthread.php?tid=15... where dissolved .NO apparently behaves differently from gaseous .NO interacting
with oxygen with a near total absence of eventual nitrate creation.
[Edited on 23-7-2022 by AJKOER]
[Edited on 23-7-2022 by AJKOER]
|
|
|
Lionel Spanner
Harmless
Posts: 45
Registered: 14-12-2021
Location: South Yorkshire, UK
Member Is Offline
|
|
Your man Experimental Chemistry has a nice video on preparing potassium nitrite via calcium formate.
https://www.youtube.com/watch?v=BhBxDkU7AmI
Industrial chemist rediscovering the practical pleasures of pure chemistry.
|
|
|
Antiswat
International Hazard
Posts: 1621
Registered: 12-12-2012
Location: Dysrope (aka europe)
Member Is Offline
Mood: dangerously practical
|
|
wow. 68% yield of KNO2 starting from Calcium Formate and KNO3, heated at about 300*C, no explosively exothermic reaction
sodium formate may be acquired in 25kg bags as a special de-icer, its used especially for areas that gets very cold but also to avoid salt getting
onto vehicles, aircrafts etc.
sodium nitrate should also be very much doable
2KNO3 + (HCOO)2Ca = 2KNO2 + CaCO3 + H2O + CO2
this seems to be exactly what we have been hoping for to pop up in regards to reduction of nitrate salt. could formic acid maybe reduce nitric acid to
nitrous acid?
The Reaction of nitric acid with formaldehyde and with formic acid and its application to the removal of nitric acid from mixtures
https://onlinelibrary.wiley.com/doi/abs/10.1002/jctb.5010080...
"Nitrites do not react with formaldehyde in neutral solution, " HNO2 may infact be formed in this reaction, it seems.
i see a comment in the calcium formate method video
"nitrite into HCL gives largely nitrosyl chloride"
would this not imply that it can maybe go the other way around again, so NOCl + NaOH = NaNO2 + NaCl?
HCl + KNO3 = NOCl (basically)
anyhow back to calcium formate method:
calcium formate is about 16g/100mL (roughly same 0-100*C)
sodium formate is 49-160g/100mL
CaCl2 is 60 to 160g/100mL
CaCl2 + NaForm = CaForm + NaCl
fractional crystallization would work- not that NaCl would really be a big issue as impurity by my assumptions
could we maybe directly use sodium formate for this reduction instead?
thank you very much for this input @Lionel Spanner
|
|
|
Antiswat
International Hazard
Posts: 1621
Registered: 12-12-2012
Location: Dysrope (aka europe)
Member Is Offline
Mood: dangerously practical
|
|
Ca(NO3)2 + 2NaForm = CaForm + 2NaNO3
164g + 70x 2 140g = BOIL THIS DRY, combust
before / after total weight of dry substance
304g = 195g
i react it at about 360*C, it takes maybe 10 minutes before it starts to react, it doesnt evolve a lot of smoke but it does smell like a nitrate
pyrotechnic composition so thats very annoying if you react too much at once.
https://gyazo.com/c414de838c4d0d7ac40e7399deb23d6f
(COOH)2Ca + 2 NaNO3 = 2 NaNO2 + CaCO3 + CO2 + H2O
130g + 170g = 138g + 100g
dissolve in water, boil NaNO2 dry or use as solution
i have tested a smaller sample of 10 grammes with IPA and HCl
when the IPN is formed it makes the polarity of the IPA seperate out so you get a very clear indication
https://gyazo.com/95df06a3975a0ba352fecd3a3db5bebb
thereafter i ignited the gasses in the flask and typical nitrite flame was seen. its also vasodilating.
its ideal to dissolve the soluble contents in water before adding acid as it causes a lot of effervescence, namely HCl
it may be possible to take a concentrated NaNO2 solution and dump into EtOH to precipitate out the NaNO2 for easy isolation as NaNO2 is 4.4g/100mL
solubility in EtOH
this procedure can be done inside if done in small quantities, 100 grammes was too much
my heating device is a single hotplate, a stainless steel pot ontop of that which is isolated with Al2O3 ceramic wool, secured by a bolt + washer +
nut going through top of the pot
i shall attempt further to simply react Ca(NO3)2 and NaFormate by direct decomposition so i dont have to dissolve that in water, and then boil that
dry
i may add some Al2O3 because the fertilizer i get my Ca(NO3)2 is a mix of ammonium salt and Ca(NO3)2 roughly 90-10% ammonium salt being the latter,
which can decompose... very rapidly on an unfortunate day- i might just do this reaction with homemade Ca(NO3)2 just to be completely sure, energetics
can be very powerful especially if situated on a hotplate covered by a pot
i have no guesstimates for yields yet but this appears to be how were gonna be making nitrites in the future
only things i have to add is that calcium formate decomposes thermally into calcium oxalate- so calcium oxalate should maybe be attempted with sodium
nitrate?
|
|
|
Myc
Harmless
Posts: 3
Registered: 30-5-2022
Member Is Offline
|
|
I tried a small batch of the above method (sodium formate and calcium nitrate) too. The reaction in the crucible was rather enthusiastic and measured
over 320C. While some of the nitrite salt survived this I suspect there was also significant decomposition at this temperature (this supposedly
happens above about 300C). So I guess the product has sodium oxide/hydroxide in there too?
|
|
|
Σldritch
National Hazard
Posts: 263
Registered: 22-3-2016
Member Is Offline
Mood: No Mood
|
|
Hm, is oxalic acid available dirt cheap as some product? I've haven't had much luck, but, I've considered making sulfuric acid from Ferrous Sulfate
(which is dirt cheap itself) with it. The by-product would be Ferrous Oxalate Dihydrate. Maybe worth trying the reaction with that as well if one
could end up with a lot of it as a byproduct...
EDIT: Huh, apparently Calcium Oxalate is almost three orders of magnitude less soluble than Calcium Sulfate.
[Edited on 25-9-2022 by Σldritch]
|
|
|
| Pages:
1
..
12
13
14 |
|
![[*]](images/xpblue/default_icon.gif){kind=icon}
