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Xenoid
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@ Rosco, tentacles
Yeah, there is no problem with wetability. I didn't worry about the filtering because the anode surface is vertical and we are not looking at
achieving optical quality films here, so I was not too concerned about "stuff" settling out. Yes, I've had a second round of haze, this time whiter,
the solution is quite hazy now (15 hours).
@ tentacles
I don't understand why you are having problems with the Bi(NO3)3. As outlined earlier, all I did was add small lumps of Bi to 68% nitric acid, until
the reactions stopped, it then crystallised by itself. Very vigorous reaction. Are you sure you have Bi, and not some alloy. Can you do some physical
tests on your Bi (density, MP). Bi is "readily attacked by both dilute and concentrated nitric acid, forming the corresponding salt" (Mellors).
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tentacles
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Xenoid: The package obviously said Bismuth, but I have no idea of the purity. Does yours turn blackish while the reaction is driving forward? Mine
reacts quite vigorously at room temp with dilute or concentrated nitric. It melts at a pretty low temperature, flows very quickly, and is hard and
brittle. This second "round" of bismuth dissolution was done with the white(eggshell white maybe) ppct from the previous reaction, plus some bits of
Bi metal, in the freezer with about 20ml of 70% nitric. The reaction is still proceeding - how much excess nitric did you use?
I can do a MP test at least, now that I have a thermocouple. I don't know that I have enough of a sample to test density very accurately. Maybe I'll
pick up more some time, or perhaps I'll wait on your Bi-MnO2 tests?
So MnO2 is out for perchlorate production, unless a doped variety proves good, but it sounds viable to make the chlorate to convert with something
else.
[Edited on 13-2-2008 by tentacles]
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Rosco Bodine
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I just did a melt test on my reputedly "bismuth" non-lead fishing sinkers , expecting to get a pool of metallic bismuth
separating from molten plastic , but that didn't happen ....
so WTF is this black powdery crap , maybe Bi2O3 ???
The smell indicates a polyethylene thermoplastic binder ,
smells like paraffin burning after you blow out a candle
and the wick ember is smoking . I have just heated
the stuff till melting and then let the plastic vapors ignite and burn off . After I ash this grungy garbage down to
carbon and whatever is left , I will see what some nitric acid does to the residue . Just hope the manufacturer
hasn't sold us iron oxide filled plastic at bismuth prices .
Iron or magnetite is precisely what it is  a magnet test just told me that much
......those sorry ass low down dirty
pieces of dog shit ......there's no bismuth in these no lead sinkers , they substituted iron when bismuth got expensive
Now I am going to have to order some for real bismuth from a metals dealer .......no OTC fishing sinker bismuth anymore .
pass the word , check with a magnet to see what you got .
[Edited on 13-2-2008 by Rosco Bodine]
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Xenoid
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@ tentacles
I did my dissolution in a 100 or 150 ml beaker, about half full of 68% nitric acid, so about 50 - 70 mls. I initially added a piece of Bi about 2 cc
in volume. For some silly reason I was thinking H2 would be evolved and I got quite a surprise when all the NO2 was evolved. I had to take a big
breath and move it all well away from the house. The reaction carried on all day, and I kept on adding small pea sized lumps. I left it outside
overnight and all the Bi had dissolved by morning and the beaker was almost solid crystals. I left it to warm up a bit, and tested the remaining
nitric with a bit of Bi, it was still reacting so I drained the crystals and put them in a container. I remaining nitric kept reacting for the rest of
the day, just a tiny stream of bubbles, eventually I added another chunk of Bi, and when the reaction appeared to cease I put it in the fridge, this
again totally crystallised, with the remaining chunk of Bi in the middle.
The MnO2 just doesn't appear to be physically and chemically strong enough in a perchlorate cell, seems to be torn to bits (hydrated MnO2 crud) by the
oxygen evolution. Maybe having some Bi will help. The MnO2 seems great in a chlorate cell, well even the Co3O4 lasted for a couple of weeks. Yeah, I
think a long lasting anode could be made with the right combination, provided the current density is not too high!
@ Rosco
"BISMUTH" - Beijing Industrial Smelting and Metal Utensil Transmutation Holdings, this company is well known in the fishing industry for producing
fraudulent products!
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chloric1
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| Quote: | Originally posted by Xenoid
@ Rosco
"BISMUTH" - Beijing Industrial Smelting and Metal Utensil Transmutation Holdings, this company is well known in the fishing industry for producing
fraudulent products! |
LMAO! Xenoid you are soo silly! If it is from China then it should be magnite with a little lead. I guess 5% lead would be considered non-lead by Chinese standards.
Fellow molecular manipulator
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Rosco Bodine
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Accept no substitutes !
Be careful where you dip your rod isn't Madame Butterfly 
http://www.youtube.com/watch?v=IMsnqQHOwFg
Evidently there was at one time a real bismuth fishing sinker sold under that same brand name as I got , but they phased out the bismuth when it
became expensive
and what I got was shit , instead of bismuth .
Anyway , I ordered some genuine reagent grade metal shot .
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tentacles
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I'm thinking that my "Bismuth" fishing weights were nothing more than tin, as the white powdery precipitate is non water soluble and quite unhappy. Or
perhaps some bastard Tin/Bismuth alloy. But I thought that Tin/Bi alloys were fairly malleable, whereas the higher % Bi ones were quite brittle. I
read something to that effect when I was looking up solder alloys. But I DO get NO2 evolution, but I suppose this would be the case with tin as well
at least at room temps, but at low temps (ie in my freezer!) I should get stannous nitrate at least.
Well, if the Bi pans out I will order some trans-border, but until then.. I will sit and wait, and experiment. Maybe I'll work on making some good
chlorate anodes, and coating PbO2 over the doped tin oxide.
Edit: one last edit, my friend may have some of that subnitrate (pottery/pyro grade), which evidently dissolves in dilute nitric to form the nitrate.
It's either that, or the subcarbonate, or trioxide. Any of those should work equally well.
[Edited on 13-2-2008 by tentacles]
Ok, so I lied, and I've been drinking beer... I just re-read that comment from Rosco "and what I got was shit , instead of bismuth." I envision
factory workers, hard at their jobs pressing turds into a sinker shape with plastic resin, just for Rosco.
[Edited on 13-2-2008 by tentacles]
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12AX7
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Incidentially, tin-bismuth alloys have very low melting points, the eutectic being something like 120C. If not for this, such alloys would be
acceptable replacements for leaded solder in electronics (see RoHS controversy). This is of course related to such alloys as Wood's metal, which
contains a few other eutectic-lowering elements, pushing the melting point under 100C.
I suppose, after some nitric acid, some of such alloy would be anode-precoat-in-one?
Tim
[Edited on 2-13-2008 by 12AX7]
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Rosco Bodine
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The cheapest source I could find for tin and bismuth
is here , but there is a 10 pound minimum . Anyway
that might fit okay if someone was casting some serious
magnetic application components and needed the Bi
in quantity .
http://www.huntersbismuth.com/pricing.html
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Xenoid
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| Quote: | Originally posted by tentacles
....but at low temps (ie in my freezer!) I should get stannous nitrate at least.
....my friend may have some of that subnitrate (pottery/pyro grade), which evidently dissolves in dilute nitric to form the nitrate. It's either that,
or the subcarbonate, or trioxide. Any of those should work equally well.
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I'm planning on making some stannous nitrate next. I believe it requires 30% nitric acid and temperatures less than 20 oC. according to the info.
posted by Rosco. So it may still not work with your 70% acid. I am waiting for some cooler weather. I have melted some of my tin and let it dribble
into a bucket of water, the drops literally explode, and produce tin "clumps" with a very large surface area. This is easier than what I did for the
SnCl2 which involved using a coarse wood rasp to "file" tiny shavings of my Sn hunk. It is quite effective but hard work.
I'm not sure about the subnitrate dissolving in DILUTE HNO3 the reaction for it's formation is as follows;
Bi(NO3)3 + H2O <--> BiO.NO3 + 2HNO3
You will require conc. HNO3 (68%) to drive the reaction the other way!
The trioxide would be useful to make the chloride from conc. HCl as well. Otherwise one needs aqua regia to dissolve
Bi metal to make the chloride. Bismuth trichloride can be dissolved in a little water to form a syrupy liquid, go too far and a white ppt. of BiOCl
results.
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Xenoid
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Some Good News and Some Bad News
I have finally pulled the plug on Hubert and non-Purple Haze. They were still producing KClO3 but I have grown tired of this combination and besides I
wanted the stirrer/hotplate for other things. The anode/cell has run for 1092 hours (45.5 days) and a total of 2299 Amp hours. I still have to
redissolve all the separate lots of KClO3 obtained and recrystallise it.
On the oxidative soak front, after 72 hours all that seems to have happened is that the lovely blue/black Co3O4
coating appears to have been stripped off and is lying at the bottom of the test tube in the form of an amorphous, brownish pile of gelatinous
precipitate! The new anode looks worse than "Hubert" after 1000 hours in a chlorate cell.
My first attempt at making stannous nitrate has ended in failure. I started with about 50 mls of cold 30% nitric acid. I added bits of Sn slowly and
kept the dissolution running in the fridge at <5 oC. The solution just got thicker and more viscous and eventually filled up with a "dun" coloured
ppt. overnight, there were bits of "golden coloured" stuff floating around in the mess. From various readings I believe hydrated tin(II) oxide is gold
coloured! I am now trying to extract the filthy coloured precipitate for further experimentation.
I have started a second stannous nitrate attempt, this time using about 7% nitric acid. The reaction is proceeding slowly in the fridge, and at this
point is still clear, with the exception of a little black/grey powder near the Sn pieces.
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Rosco Bodine
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| Quote: | Originally posted by Xenoid
On the oxidative soak front, after 72 hours all that seems to have happened is that the lovely blue/black Co3O4
coating appears to have been stripped off and is lying at the bottom of the test tube in the form of an amorphous, brownish pile of gelatinous
precipitate! The new anode looks worse than "Hubert" after 1000 hours in a chlorate cell. |
Is there any color tint left to the exposed or remaining interface ? I'm wondering if the stripping stopped there at the interface of a mixed Ti and
Co spinel or also reduced it to the bare Ti substrate . It sounds like the SnCl2 reduced the Co3O4 to Co(OH)2 . So that probably means oxidative soak
deposition is out . An electroless deposition that starts with an already oxidized Sn(+IV) compound might work if the Co3O4 will withstand the
alkaline condition . However I would expect the Co3O4 would likewise be degraded by that alkalinity . Contact time is going to be a factor with
whatever precursors might attack the Co3O4 .
| Quote: |
My first attempt at making stannous nitrate has ended in failure. I started with about 50 mls of cold 30% nitric acid. I added bits of Sn slowly and
kept the dissolution running in the fridge at <5 oC. The solution just got thicker and more viscous and eventually filled up with a "dun" coloured
ppt. overnight, there were bits of "golden coloured" stuff floating around in the mess. From various readings I believe hydrated tin(II) oxide is gold
coloured! I am now trying to extract the filthy coloured precipitate for further experimentation.
I have started a second stannous nitrate attempt, this time using about 7% nitric acid. The reaction is proceeding slowly in the fridge, and at this
point is still clear, with the exception of a little black/grey powder near the Sn pieces. |
The stannous nitrate is likely to have the same reducing effect on the Co3O4 if the contact isn't brief and the reaction driven differently . The
possible exception there would
be the thermally driven flash coating sort of idea which I mentioned , which is a long shot but could work .
Using stannic nitrate as a dip coat would seem a better bet ,
or using another stannic salt SnCl4 wouldn't have the reducing effect on the Co3O4 . Applying the SnO2 as a hydrosol , a gel , or a mixed polymer gel
preformed is another possibile approach . Personally I remain most intrigued by the mixed valency polymer having usefulness
in several ways , including as a liquid carrier for colloidal
hydrated SnO2 derived from simple atmospheric oxidation of an SnCl2 solution . The polymer may not even require the added thickening and might be
possible to be used alone if
it is sufficiently viscous . An alternate thixotropic thickener
for the mixed valency polymer could be stannic oxide derived
from the usual nitric acid oxidation reaction with tin .
And there's always the standby alternative of SnCl4 or an
alcoholate derivative .
I'm sure there's one or more of these schemes that will work
without stripping the Co3O4 like the SnCl2 evidently does .
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tentacles
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| Quote: | Originally posted by Xenoid
On the oxidative soak front, after 72 hours all that seems to have happened is that the lovely blue/black Co3O4
coating appears to have been stripped off and is lying at the bottom of the test tube in the form of an amorphous, brownish pile of gelatinous
precipitate! The new anode looks worse than "Hubert" after 1000 hours in a chlorate cell.
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My anodes don't seem to be losing the CoO coating - both have a hazy coating on them, and I plan on doping and baking them at some point today. One
does look a bit better than the other though. I will take pictures. The precipitate in the soak solution does have a slight yellow tinge, but it's
fluffy like when you first make the solution. I don't see how there could be enough tinge in the precipitate to account for all the cobalt.
Did it seem to start stripping off the Co from the start, or is this something that seemed to happen after a couple of days? Maybe the solution is to
put a thin coat of SnO2 on, dope, bake, and then put on a beefy layer.
Were your Ti pieces hydrided before the Co, or just bare etched? I've been hydriding mine, the Co really seems to stick better (as I think you
mentioned first?).
Any idea if BiCl3 could be used to dope instead of the SbCl3? Or should I use I should be getting some BiO3 today. 10-20g but enough to work with for
doping.
[Edited on 16-2-2008 by tentacles]
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tentacles
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Update: I took another look at those anodes, and it seems Xenoid's assessment is correct - other than a couple streaky spots, the CoO appears to have
been stripped off, as well as my hydrided layer!
That would leave us looking to another method for the SnO2... Rosco, why wouldn't thermal decomposition of stannous nitrate work, as in a dip (perhaps
even drying in a cold environment) and bake?
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Xenoid
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| Quote: | Originally posted by tentacles
That would leave us looking to another method for the SnO2... Rosco, why wouldn't thermal decomposition of stannous nitrate work, as in a dip (perhaps
even drying in a cold environment) and bake? |
Well, I can't even seem to make stannous nitrate, my second attempt hasn't worked either, despite being very dilute, and very cold. I ended up with a
pale yellow solution and ppt. I put some of the supernatent liquid in a teaspoon and heated it to dryness, a very small amount of white residue
remained.
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Rosco Bodine
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Stannous nitrate is a reducing agent so it is reacting with the Co2O3 . It would attack PbO2 the same way . It's the same effect as when you leave a
cell open circuit , with
materials present which can react with and reduce the anode coating .
Stannic nitrate would probably be okay . Being already at the +IV higher oxidiation state , it shouldn't attack the Co2O3 . And its contact time
before baking will be reduced also .
[Edited on 19-2-2008 by Rosco Bodine]
Attachment: summary Nitric Acid products with Tin metal.pdf (112kB)
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tentacles
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So we need to try synthesizing the stannic nitrate? It sounds a bit difficult.
"Evidently for obtaining the Sn(IV) nitrate , only an indirect route is practical , where hydrated stannic oxide
( stannic hydroxide Sn(OH)4 ?? or "stannic acid" ?? )
is precipitated from a solution of an Sn(IV) compound
upon careful *partial* neutralization by a base slowly with vigorous stirring , whereupon the hydrated stannic oxide is obtained as a precipitate ,
rinsed by decantation , and
drained , dried without heating . This hydrated stannic oxide
can then be used to neutralize HNO3 completely , keeping
temperature well below 50 C , to form a solution of Sn(IV) nitrate ."
So basically, we need to start with a stannic salt, which pretty much means buying one if we want to be certain of what we have? Or is there a tin(iv)
salt that is remotely easily made?
[Edited on 19-2-2008 by tentacles]
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Rosco Bodine
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The precursors for baked tin oxide coatings which are applied as liquid and then baked are all sol-gel type of systems , no matter what compounds from
which they are derived , that sol-gel transition is there .
With any tin compounds in aqueous solutions , it is generally
an unstable system that is more or less of one compound
in mixture with others of a series of hydrolysis products .
Attached are a couple of references which give a look at the complex chemistry involved in the reaction of nitric acid with
tin metal . I'll attach one to my earlier post as an edit .
Anyway , the interest in the nitrate of tin is simply as one candidate compound , mostly because it is likely going to form
a sol automatically in its making , which is also a Pytlewski polymer of the sort described in US3890429 .
A different sol of only the higher valency hydrated tin oxide
is described by US6777477 . This would likely have similar
behavior to the colloidal silica described in the Pytlewski patent applied subsequent to the polymer . It was the differing electrostatic properties
anticipated for these materials which was the basis for my suggestion of sequencing , the layers should stick together by attraction
of one coating for the next .
If nitrate of tin is problematic , don't get stuck on nitrate ,
as the chloride should work as well , and in the case of the sol of US6777477 the precursor is irrelevant anyway since
it is neutralized to get the stannic oxide hydrate , then
peptized with ammonia to a hydrosol .
US1879022 gives another look at some reaction parameters which are favorable for precipitation of hydrated stannic oxide gel , which may be rinsed
free of its neutralization byproducts , for example the chloride or nitrate anion ,
differing here from the situation with the Pytlewski polymer
where the anion remains an included structure of the polymer . This gel may be converted back to a colloidal suspension , a sol , by peptization with
ammonia .
Mixed sols of different sorts like tin with bismuth or antimony become doped colloids as the dopant is nuclei for larger particles hydrated SnO2
condensing and entrapping the dopant . This is identical to the mechanism by which flocculents are used in water treatment to precipitate impurities
, in this case the impurity being the intended dopant material .
When the pH is correct , the film of the sol on dehydration by baking will adhere to the substrate as a sintered glaze of
SnO2 .
[Edited on 19-2-2008 by Rosco Bodine]
Attachment: summary Tin reactions with HNO3.pdf (216kB)
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Xenoid
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Well, that last abstract "Metastannic Acid and its Compounds" is as clear as mud ....!
Both my attempts at making stannous nitrate are sitting on my bench and both now look pretty much the same. A yellow / white precipitate in a yellow
liquid, the yellow liquid has a dark yellow skin on the top.
I am currently trying an oxidative soak SnO2 coat directly onto an etched Ti rod. I filtered the soak solution to remove the initial floc. but now a
yellowish white ppt. has formed (I seem to be plagued with yellowish-white ppt. at the moment). Not sure if anything is going on the rod. I am using
the exact temperatures and molarities described in the Japanese paper, not sure why ?metastannic acid is precipitating.
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Rosco Bodine
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Yes it's a brain strainer to follow the complex chemistry and hydrolytic reactions , of these polyvalent and amphoteric metal oxides / salts /
oxy-salts / basic salts / hydroxy oxides / ect . on and on it seems till a good baking simplifies everything and makes a well behaved SnO2 from all the misbehaving precursor mixtures . And pH is very important
not only to adhesion , but it also affects the decomposition
temperature curve , and what is good for one isn't necessarily good for the other .
One thing about the Pytlewski polymer as a precursor for baked coatings is that all the patents either run from it completely or mention it as if it
was the elephant in the room . The deepening color with increased polymerization
is what we want to see there . Possibly even hybrid polymer
having both nitrate and chloride anions , or nitrate and acetate could be a good precursor for baked coatings .
Anyway , I still believe the alternating scheme makes sense .
And with the oxidative cold soak , that could still work with
a slight anodic polarization to protect the spinel . Or one of the sol-gel deposition methods which works similarly as oxidative soak , sans the
oxidation for working from a solution of the Sn+IV salt originally . Stannic nitrate solution
diluted to 4.75 grams per liter tin content as the metal might deposit the same sort of film spontaneously at room temperature , and gradually
precipitate the gel going to completion just sitting there .
Attached is a paper concerning the hydrated oxide of tin(+IV)
and the pyrolysis curves for the material gotten at different pH .
Of course no discussion of tin would be complete without mention of this variety 
http://en.wikipedia.org/wiki/Rin_Tin_Tin
[Edited on 19-2-2008 by Rosco Bodine]
Attachment: Stannic Oxide Hydrate.pdf (661kB)
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Rosco Bodine
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Here is an excerpted old textbook chapter which seems to better describe the subtle complexities of tin chemistry , which first caught the attention
of Berzelius with the origination of the term isomer for these identified isomers , which are the alpha and beta forms of stannic "hydroxide" ,
thereafter being commonly called the stannic and "meta"stannic isomers respectively , along with their associated derivatives .
Historically , Woehler is credited with the first observation of
isomers in comparing fulminic acid and cyanic acid , and later urea and ammonium cyanate , as being compounds having identical chemical composition ,
yet different structure and properties , and it would later be Berzelius in observing the
parallel for alpha and beta stannic hydroxide , who would originate the term isomer .
The alpha isomers are the "soft" forms which are readily reactive , whereas the metastannic isomers are a polymerized form having the same chemical
composition but
structurally different , much more resistant to reaction with
other materials for being essentially the alpha isomer having already reacted with itself , to form a 5 molecule "meta" unit .
Some of the pages are poorly scanned , but this should
help understanding Berzelius' original observations and naming of isomers . At about the bottom of page 5
(416-417) is where it gets to the distinctions concerning the alpha/meta transitional forms . Neutralization of the stannic salts with ammonium
hydroxide follows the same track leading to a precipitation of alpha stannic acid ( tin oxy-hydroxide , tin oxide hydroxide , basic tin hydroxide ? )
and this parallels what occurs with lead hydroxide . The amphoterism allows formation of an alpha stannate of the neutralizing base if additional
base in excess of that used for neutralization is present , or alternately a tin salt of an acid can be made by addition of an acid like HCl or HNO3
ect. to the rinsed precipitate of alpha stannic acid , tin (+IV) oxy-hydroxide .
[Edited on 20-2-2008 by Rosco Bodine]
Attachment: Tin chapter from Inorganic_Chemistry.pdf (409kB)
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Rosco Bodine
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| Quote: | Originally posted by tentacles
So we need to try synthesizing the stannic nitrate? It sounds a bit difficult. |
No pain , no gain Really it is a bit convoluted with regards to the steps
required in working up any tin based reagents
in any sort of solution , since most of them are unstable .
Even pure tin metal itself is unstable and its compounds tend to inherit instability . Many tin reagents will have to be made
and used fresh , that is just the nature of the compounds .
You can alternately make your alpha stannic acid precursor via sodium stannate , neutralized with HCl and rinsed well ,
and then reacted with nitric acid . There are several different
synthetic routes .
| Quote: |
"Evidently for obtaining the Sn(IV) nitrate , only an indirect route is practical , where hydrated stannic oxide
( stannic hydroxide Sn(OH)4 ?? or "stannic acid" ?? )
is precipitated from a solution of an Sn(IV) compound
upon careful *partial* neutralization by a base slowly with vigorous stirring , whereupon the hydrated stannic oxide is obtained as a precipitate ,
rinsed by decantation , and
drained , dried without heating . This hydrated stannic oxide
can then be used to neutralize HNO3 completely , keeping
temperature well below 50 C , to form a solution of Sn(IV) nitrate ." |
Yeah , by well below ...about 50C below there would probably be about right , I
would do that neutralization
in an ice bath , and probably keep the stuff under 10C ,
never even go close to 50C .
| Quote: |
So basically, we need to start with a stannic salt, which pretty much means buying one if we want to be certain of what we have? Or is there a tin(iv)
salt that is remotely easily made? |
Well lemme think here a minute . If you took tin and dissolved it in concentrated nitric acid with heating ,
you would get metastannic acid precipitated and that's a
a Sn(+IV) compound , which on fusion with NaOH would
depolymerize and form alpha stannate of sodium . On
neutralizing that with HCl , then alpha stannic oxyhydroxide
would precipitate and after rinsing could then be neutralized
in the cold with HNO3 to give a solution of Sn(NO3)4 .
But it would be a lot easier probably to just dissolve tin
in aqua regia to get SnCl4 in solution and then neutralize
that with ammonium hydroxide to precipitate alpha stannic
oxyhydroxide ( alpha stannic "acid" ) and then rinse that ,
and neutralize in the cold with HNO3 to get a solution of
Sn(NO3)4 .
Both routes use HNO3 and HCl , but the second is probably
easiest .
Tin dissolved in HCl plus potassium nitrate reportedly works also , and it would be my guess that NaNO3 or NH4NO3 would possibly work too for
producing an aqueous solution of SnCl4 suitable for use as precursor for alpha stannic oxyhydroxide , gotten after neutralization by ammonia and
rinsing the precipitate free of byproducts .
All this stuff about the natural polymerization tendency
of tin compounds makes old Pytlewski seem like one
much smarter pollock all of a sudden
There's a bit more general tin chemistry in the attachment
which is a more general description. Sometimes seeing the same thing in different words , or an added bit here and there completes the picture when
no one text seems to cover it all .
[Edited on 20-2-2008 by Rosco Bodine]
Attachment: Tin chemistry summary.pdf (204kB)
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Rosco Bodine
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something very interesting
Two posts above I posted a chapter from an old inorganic chemistry textbook . On page 6 (417) in the middle of the page is a reaction for stannic
chloride with sodium sulfate , and very possibly a similar reaction occurs with ammonium nitrate , the product being a precipitate of alpha stannic
oxyhydroxide .
There is another old text circa 1876 which refers to this .
I am attaching the page here which shows what I believe
is a mangled and incorrectly written reaction equation .
There is some confusion in the naming of compounds in
that era as well as mistaken or misprinted identification on the number of chlorines held by stannous versus stannic salts , so this brings
uncertainty when referencing these ancient texts . Trying to reference this from the original
german journal article may or may not clarify the matter as the reference is from the year 1852
http://www3.interscience.wiley.com/cgi-bin/abstract/10975695...
J. Löwenthal , Journal für Praktische Chemie , Volume 56, Issue 1 , Pages 366 - 374
However , this parallel reaction for ammonium nitrate with
stannic chloride , if that is what it turns out to be , could
lead to a shortcut method for conversion of tin metal
to a precipitated alpha stannic oxyhydroxide , simply
by dissolving tin metal in a mixture of hydrochloric acid
and ammonium nitrate , or perhaps in a ternary mixture
of HCl + KNO3 + NH4NO3 .
The original german article is going to need to be translated
to get at the possibility of clarifying this reaction , if by chance
the reaction is identified correctly by the good german chemist of that era . If it's true , this could be a very good find , since it would greatly
simplify the making of *any*
Sn(+IV) compounds desired via two easy steps from the metal using mundane materials and mild conditions .
[Edited on 21-2-2008 by Rosco Bodine]
Attachment: p 279 from Quantitative_Chemical_Analysis 1876.pdf (168kB)
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Rosco Bodine
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The Lowenthal article has been obtained and is attached. Hopefully a translation will clarify the discrepancy which I believe I have found in this
older literature about this reaction .
I think the reaction is described incorrectly in the journal .
What I am supposing here from the parallel reaction using
sodium sulfate described in the more modern reference ,
is that the actual reaction between stannic chloride and
ammonium nitrate above 50C would be as follows :
SnCl4 + 4 NH4NO3 + 3 HOH ----> SnO(OH)2 + 4 NH4Cl +
4 HNO3
The reaction is temperature dependant and dilution dependant ,
the volume would need to be such that the HNO3 byproduct
is estimated about 0.15 molar . The filtered and rinsed
alpha stannic oxyhydroxide could be converted to
alpha stannic nitrate in the cold using a more concentrated HNO3 .
So if this works the way I am thinking it probably does ,
the process can start with tin metal , HCl and KNO3 .
Sn + 8 HCl + 4 KNO3 ----> SnCl4 + 4 NO2 + 4 KCl + 4 HOH
Or even better NH4NO3 might substitute for the KNO3 in the
initial dissolution of the tin .
The two reactions probably can’t proceed simultaneously because of
the greater acidity requirement for the dissolution of the tin and the
more concentrated reaction mixture . However it should work as a
one pot synthesis , treating the SnCl4 and byproduct KCl solution ,
with ammonium nitrate solution sufficiently dilute to result in an
0.15 M endpoint molarity of total acids for the completed reaction mixture .
If the translation isn't revealing of what is the true story
for this reaction series , then an experiment should resolve
the matter . Anyway , pardon my departure concerning
this interelated topic of tin chemistry , but this could solve
a lot of problems if it works as hypothesized.
update : woelen is going to take a look at this and see if any sense can be made of the 1852 journal article .
I have a sneaking suspicion that the Lowenthal reaction probably works , but that possibly the product is not the desired alpha isomer but the meta
isomer , or a mixture favoring one or the other dependant upon temperature , the hotter the reaction the more meta isomer , but that's just my guess .
It could also be a mixed product basic salt which
confused the analysis and identification . This is probably one where the references are uncertain to the point that
only experiment will show what you actually get via such
a reaction series .
[Edited on 21-2-2008 by Rosco Bodine]
Attachment: eue Methode Zinnoxyd zu fällen und von andern Körpern zu trennen, sowie neues Verfahren, seidene, wollene und baumwollen (393kB)
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tentacles
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A tiny bit on topic (considering the current discussion of those damned tin compounds) -
Ordered me one of these:
3715 Tin tetrachloride pentahydrate, Purity: min. 98.0%, Grade: Pure, crystalline lumps, Size: 500g $19.00
and
3598 Lead oxide, yellow, Purity: (complexometric) min. 98%, Grade: Reagent, Size: 1kg $28.89
Should be enough SnCl4 to last several lifetimes. Any Canadians that want a dash or two, let me know as I will make my run down south to pick this up
in a few weeks perhaps. I've seen what Canadian chemical suppliers want for (anything), and it's frightening.
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