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AJKOER
Radically Dubious
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Quote: Originally posted by Bedlasky  |
Titration with silver nitrate is far quicker. You can use K2CrO4 or fluorescein as indicator.
[Edited on 2-1-2022 by Bedlasky] |
Well, perhaps a bit faster than the reportedly fast action of Al with KNO3 in a dilute acidified solution with added NaCl and a trace of Cupric ion.
However, the latter is definitely cheaper and further benefits as readily available reagents.
Also, AgNO3 is a light sensitive reagent, which adds 'insult' to the 'injury' just suffered by your bank account. Albeit, one can further purchase
NaOH to recycle your AgCl to Ag (but this is still not AgNO3 which requires yet another purchase, or preparation, of HNO3).
[Edited on 2-1-2022 by AJKOER]
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Bedlasky
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| Quote: Originally posted by AJKOER |
Well, perhaps a bit faster than the reportedly fast action of Al with KNO3 in a dilute acidified solution with added NaCl and a trace of Cupric ion.
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And then what? How do you find how much nitrate do you have?
| Quote: Originally posted by AJKOER |
However, the latter is definitely cheaper and further benefits as readily available reagents.
Also, AgNO3 is a light sensitive reagent, which adds 'insult' to the 'injury' just suffered by your bank account. Albeit, one can further purchase
NaOH to recycle your AgCl to Ag (but this is still not AgNO3 which requires yet another purchase, or preparation, of HNO3).
[Edited on 2-1-2022 by AJKOER] |
I just pointed out, that rather than bothering with precipitation, filtration, washing and drying light-sensitive AgCl, it is better and much quicker
to perform titration. And AgNO3 isn't that sensitive like you suggest. If it would be so sensitive, why would be argentometry so widely used method?
Cheaper alternative is bromatometry. You can precipitate CuCl, wash it, dissolve in HCl and titrate it with KBrO3 solution. However, this particular
mixture also contain nitrate, which will oxidize CuCl. There is other option, to precipitate Cu2O instead of CuCl. Nitrate won't oxidize Cu(I) in
alkaline solution. But there are also ammonium ions, which will be converted to ammonia in alkaline solution, which dissolve your Cu2O to form soluble
[Cu(NH3)2]+. So you see why this method cannot be used.
[Edited on 3-1-2022 by Bedlasky]
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Fyndium
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Big processes benefit from large amounts. When you load 10 000 tons of each in a reactor pool, and add that every day, you can keep the Solvay cycle
running and precipitate the desirables in plenty amounts. But you still keep that base amount dissolved in there.
So, for amateur who wants a few kg of something once, it would be detrimental to get 25kg of each precursor and eventually lose most of them in the
process.
Also, sodium nitrate is not "one of the easiest" to synthesize in practice. Nitrates may not be directly available in pure form at all without certain
troubles.
Anyway, I usually classify stuff in 4 categories, which are 1: always bought, 2: may be bought but could be made if necessary, 3: always made, and
category 4: stuff that is just too hard to obtain, dangerous, expensive or illegal to work with.
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AJKOER
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Bedlasky:
You may be right as here is a supporting SM thread https://www.sciencemadness.org/whisper/viewthread.php?tid=82... noting the presence of impurities is likely a key factor for the induced light
sensitivity of AgNO3.
Further agreeing comment at https://www.largeformatphotography.info/forum/showthread.php...
"By itself, or mixed in distilled water, silver nitrate is not light-sensitive. Combined with halide salts, it becomes very light-sensitive, and
combined with organic materials, somewhat light-sensitive."
However, a mass of others with a diverging opinion, for example, per Google, the first provided answer at https://www.vedantu.com/chemistry/silver-nitrate (which, albeit, I will admit is likely, in my opinion, not #1 for technical accuracy alone), to
quote:
"Silver Nitrate is very sensitive to light. This means, that the chemical will react when exposed to light. So, when this is left exposed to sunlight
or any bright light, it will start to hydrolyze. This will result in the formation of black or brown colored silver oxide and nitric acid."
Also, someone once asked, and provided answers at https://www.quora.com/Why-is-silver-nitrate-stored-in-black-... :
"Why is silver nitrate stored in black bottle in laboratory?"
Clearly a switch is turned to account for this difference in narrative.
As to what causes the issue, I suspect, that it is first, the liberation of Ag metal (via light), and also the creation of Ag2O/AgOH (via transition
metal impurities and oxygen exposure), which together can apparently form a powerful photocatalyst: "The formation of visible light-driven Ag/Ag2O
photocatalyst with excellent property of photocatalytic activity and photocorrosion inhibition" here https://www.sciencedirect.com/science/article/abs/pii/S00219... .
[Edited on 4-1-2022 by AJKOER]
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AJKOER
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Just found a supporting reference to my suggested path to account for the lack of stability in (or following) light exposure of AgNO3, here https://www.researchgate.net/post/How_does_silver_nitrate_be... "Photochemical reduction of silver nitrate to silver nanoparticles in the presence
of stannous chloride was interestingly described in the attached article." where the cited article notes the present of select organics can result in
a stable solution of nano-particles. Also, see "The extra cellular synthesis of gold and silver nanoparticles and their free radical scavenging and
antibacterial properties".
I would note that the formation of nano-particles can foster the creation of hydroxyl radicals, see for example "Use of mine waste for H2O2-assisted
heterogeneous Fenton-like degradation of tetracycline by natural pyrite nanoparticles: Catalyst characterization, degradation mechanism, operational
parameters and cytotoxicity assessment" at https://www.sciencedirect.com/science/article/abs/pii/S09596... , to quote:
"Radical scavenger tests demonstrated that •OH was the main oxidizing agent generated by both solution and surface phase reactions."
And I would claim:
Ag -> Ag+ + e-
•OH + e- -> OH-
Net: Ag + •OH -> AgOH (See Eq 2 here https://pubs.acs.org/doi/pdf/10.1021/nn503459q )
2 AgOH (unstable) -> Ag2O + H2O
So, in summary, light exposure of AgNO3 leads to Ag which in the presence of an organic leads to stable nano-particles. The electrostatic properties
of such suspension in the presence of dust with transition metals promotes/recycles a Fenton or Fenton-like reaction in the presence of oxygen (see https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2626252/) forming associated •OH radicals. Per above this leads to Ag2O and with Ag a possible
powerful visible light photocatalyst (Ag/Ag2O). The photocatalyst leads to electron holes converting water into a source of •OH radicals, etc,
leading to the degradation of the AgNO3.
My suggested explanation accounts for the role of sunlight, organics, metal impurities, air exposure and a newly induced photo sensitivity of the
AgNO3.
[Edited on 5-1-2022 by AJKOER]
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Bedlasky
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I really don't understand where is problem. If you store silver nitrate in brown closed bottle in dark place, it is stable for prolonged time. And if
some silver is formed in solution, you can standardize it with NaCl anytime. There are much more problematic solutions in volumetry (like FeSO4,
TiCl3, CrCl2 etc.) and they are still used for analysis.
And I don't really get, how colloidal silver is related to storage of AgNO3 solution. Do you read that paper? They maintain silver colloidal using
cetyl trimethyl ammonium bromide. But cetyl trimethyl ammonium bromide (or another surfactant) isn't present in AgNO3 solution for analysis.
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AJKOER
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Bedlasky:
My understanding is that AgNO3 is, somewhat generally, reported as less stable in the presence of light and organic and "air" exposure (where the
latter includes not just ambient air but dust particles).
My presumption is that photochemistry, properties of nano particle suspension and air interface could possibly, with associated induced radical
formations, therein provide a possible path to an understanding of why there could be a change in the photosensitivity of AgNO3.
In the work by Hongxai Yu et al, it is noted that nano silver is a photocatalyst. Also, nitrate is a weak photocatalyst (UV). So, if nano silver is
introduced via associated light exposure, the solution becomes more photo sensitive. As whether organics increase photo sensitivity, likely yes (see
my extended comment below). Air exposure suggests to me surface chemistry inducing eventually H2O2 and Ag2O formation (more details below). Together
with photo liberated Ag, a yet more powerful visible light photocatalyst construct (Ag/Ag2O).
As per this source https://www.sciencedirect.com/science/article/abs/pii/S00456... Natural organic matter (NOM) "promoted the formation of hydroxyl radical, induced
the generation of triplet-excited state NOM and thus greatly enhanced the indirect photolysis" . With respect to Dissolved Organic Matter (DOM), per a
source https://infoscience.epfl.ch/record/223453?ln=en to quote: " is a complex mixture of thousands of organic molecules ubiquitously present in surface
waters. Its influence on the photodegradation of organic contaminants is a complicated topic. For decades DOM had been mostly assumed to have a
positive effect (i.e., promoting the degradation of contaminants), but more recently it was discovered that for some compounds, DOM can also have
negative effects (i.e., inhibiting the photodegradation of contaminants) in surface waters". Lastly, a source https://www.researchgate.net/publication/51379919_Production... notes: "Under UV irradiation, an important primary photochemical reaction of
colored dissolved organic matter (CDOM) is electron ejection to produce hydrated electrons (e-aq)." As such, light (especially rich in UV) with added
organics, in general, likely leads to the accelerated photo decomposition of AgNO3.
Note, with respect to alluded to surface chemistry, apparently, the near UV illumination of a suspension of ZnO, for example, forms measurable surface
amounts of H2O2 (see https://pubs.acs.org/doi/10.1021/j100585a011). As to mechanics, Zinc oxide, which is a photocatalyst, releases electrons (e-) at the gas water
interface with air. So I suspect, e- + O2 -> .O2- , the creation of the superoxide radical anion, which is transformed in a medium of air/water
vapor to .HO2 (or at pH < 5). Further action at the interface: .HO2 + e- -> HO2- which can apparently rapidly borrows a H+ from even water to
create the claimed surface H2O2. Then per Hongxai Yu et al, Eq (1) and (2), a product formation of AgOH ( --> Ag2O) in the likely related case of a
suspension of nano Ag (a photocatalyst).
Note, my suggested chemistry is an attempt at providing a paradigm that could possibly explain the progression in AgNO3 from "little" light
sensitivity to "high".
[Edited on 5-1-2022 by AJKOER]
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servo
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| Quote: Originally posted by Fyndium | Big processes benefit from large amounts. When you load 10 000 tons of each in a reactor pool, and add that every day, you can keep the Solvay cycle
running and precipitate the desirables in plenty amounts. But you still keep that base amount dissolved in there.
So, for amateur who wants a few kg of something once, it would be detrimental to get 25kg of each precursor and eventually lose most of them in the
process.
Also, sodium nitrate is not "one of the easiest" to synthesize in practice. Nitrates may not be directly available in pure form at all without certain
troubles.
Anyway, I usually classify stuff in 4 categories, which are 1: always bought, 2: may be bought but could be made if necessary, 3: always made, and
category 4: stuff that is just too hard to obtain, dangerous, expensive or illegal to work with. |
Well I never said I am making few grams, I am already making about 30 tons a month using Caustic soda and AN , I see an obvious benefit in making it
from salt , I say I am an amateur because I have no formal education in chemistry but I have a chemical manufacturing Unit and I make chemicals for a
living
I did say I want to challenge myself because it is a challenge but I am not doing for the fun of it but because i see obvious cost savings
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yobbo II
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What do you do with the Ammonia?
Yob
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SWIM
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I have an idea, but it may not be economically viable.
What is your cost per ton for ammonium nitrate, and what do you get per ton for sodium nitrate?
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servo
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@yobo
There is ample demand for liqour ammonia so we dissolve ammonia in water and sell it
@swim
Yes what is the idea ? it may give me some lead
cost per ton of AN is 228 USD
and Sodium Nitrate is about 680 USD currently costs me
[Edited on 15-1-2022 by servo]
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