Keras
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10 l chlorine generator
Hi folks,
yesterday, I attempted (see attached picture) the sythesis of potassium chlorate using the method described in PrepChem (I have no electrical
equipement so no electrolysis for me). Roughly, it consists in dissolving 16 g KOH and 44 g NaOH in about 70 cl water, and bubbling chlorine through
it until the solution is saturated. Then you boil it, filter and cool it to get about 15 g of potassium chlorate crystals. This is basically making
high concentrated bleach (since the pH is highy alcaline, the reaction Cl₂ + H₂O ⇌ HClO + HCl is driven almost completely to the right, as both
acids are consumed immediately after being produced).
Trivia: the bubbling of Cl₂ in the hydroxide mixture produces A LOT OF salt (as you can see on the picture), that tends to clog inside the bubbling
tube, so you have to periodically remove it and dip it into fresh water to get the salt removed and the apparatus work again. Otherwise, pression will
build up and eventually the small rubber stopper I used will pop off releasing an unpleasant puff of chlorine.
Anyways.
Problem is, I went ahead without figuring how much chlorine I would need, and ended up using (almost) all my TCCA pellets without even coming close to
saturate the solution. And since dismutation of ClO⁻ into ClO₃⁻ and Cl⁻ doesn't happen unless the hypochloric acid is in excess (pH must be
acidic), there is zilch chance to get the chlorate with a sub-stoichiometric amount. Now, 16 g of KOH and 44 g of NaOH in dissolving produce around
1.3 mol of OH⁻, and Cl₂ gives two H⁺ ions, so proper neutralisation would require 0.65 mol of Cl₂ or about 13 l.
Does anyone know if it is decently possible to generate that amount of chlorine "easily"?
Thanks!
[Edit: if I am not mistaken, that amount of chlorine could be synthesised using 160 g of TCCA and around 200 ml of 23% hydrochloric acid – the
concentration commercially available over here. I'm a bit surprised too, because if it were true, then I would probably have gotten positive results.]
[Edited on 26-8-2019 by Keras]
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Ubya
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i did not check your calculations but assuming they are right, you would need a MINIMUM of 13L of Cl2, remember that the absorbtion is not 100%
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feel free to correct my grammar, or any mistakes i make
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Pumukli
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Just from the top of my head, without exact calculations: TCCA is 90% chlorine, from 160 g TCCA you can set free 140+ g chlorine! 0.65 mol chlorine is
much less than 160 g. Check your calculations -check mine, too! I may have a mistake, but I'm in a hurry now!
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Keras
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Frankly, I put my nose at the end of the escape tube you can see at the left of the picture, and never smelt any chlorine odour. The undissolved
chlorine is heavier than air, stays in the bottle where it is redissolved at the interface air/liquid. It's not visible in the picture, because I had
just shaken the flask, but there is a large foaming of NaCl crystals throughout the reaction.
Mulling over it, I think my TCCA pellets are not 100% TCCA. It's not chlorine for pools, it's bleach pellets. They dissolve very easily in water while
giving off some gas, so I suppose the amount of TCCA in them is simply a few percent. That would explain why I didn't get as much chlorine as I
expected.
[Edited on 26-8-2019 by Keras]
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Keras
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Quote: Originally posted by Pumukli  | | Just from the top of my head, without exact calculations: TCCA is 90% chlorine, from 160 g TCCA you can set free 140+ g chlorine! 0.65 mol chlorine is
much less than 160 g. Check your calculations -check mine, too! I may have a mistake, but I'm in a hurry now! |
No, for all intents and purposes TCCA is 3 CClNO. C = 12, Cl = 36, N = 14, O = 16, so C, N, O together account for 42. That means Cl is roughly 45% of
it.
But yeah, that's a handy way. 0.65 mol of Cl₂ weigh 72 * .65 = 47 g. That mean around 100 g of TCCA should do the job. I wonder why I got 160 g in
the first place (EDIT: I stupidily multiplied .42 mol of TCCA by 232 g/mol and got 160 g, instead of 100 g! :p)
[Edited on 26-8-2019 by Keras]
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Herr Haber
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Those bleach pellets usually are Dichloroisocyanuric acid.
You can get TCCA from Amazon Germany if you are unsure what your local hardware store has.
The spirit of adventure was upon me. Having nitric acid and copper, I had only to learn what the words 'act upon' meant. - Ira Remsen
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Keras
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| Quote: Originally posted by Herr Haber | Those bleach pellets usually are Dichloroisocyanuric acid.
You can get TCCA from Amazon Germany if you are unsure what your local hardware store has. |
Ah, thanks. It is only 2/3 as efficient as TCCA, therefore around 170 g should suffice. That's about the whole contents of a box, or 40 pellets. Darn,
40 pellets to grind :p
[Edited on 26-8-2019 by Keras]
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wg48temp9
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| Quote: Originally posted by Keras | | Quote: Originally posted by Herr Haber | Those bleach pellets usually are Dichloroisocyanuric acid.
You can get TCCA from Amazon Germany if you are unsure what your local hardware store has. |
Ah, thanks. It is only 2/3 as efficient as TCCA, therefore around 170 g should suffice. That's about the whole contents of a box, or 40 pellets. Darn,
40 pellets to grind :p
[Edited on 26-8-2019 by Keras] |
The bleach tablets are usually sodium dichloroisocyanuric acid dihydrate.
But it is believed by some that the HCl also contributes to the chlorine.
I am wg48 but not on my usual pc hence the temp handle.
Thank goodness for Fleming and the fungi.
Old codger' lives matters, wear a mask and help save them.
Be aware of demagoguery, keep your frontal lobes fully engaged.
I don't know who invented mRNA vaccines but they should get a fancy medal and I hope they made a shed load of money from it.
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Pumukli
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"No, for all intents and purposes TCCA is 3 CClNO. C = 12, Cl = 36, N = 14, O = 16, so C, N, O together account for 42. That means Cl is roughly 45%
of it."
Yes, TCCA contains 45% chlorine, yeah.
What I meant to say (but was too sloppy to explain) that this is only one half of the equation, so to speak!
I should have said: "TCCA can generate 90% of its own weight as chlorine." Or something like that.
Because wg48temp9 said the other half of the truth: half of the chlorine comes from the HCl (or NaCl + acid)!!!
The real equation is this:
TCCA + 3 HCl -> Cyanuric acid + 3 Cl2
Dichloroisocyanuric acid works with same principle, contributes 2 chlorine atoms for 2 Cl2, the other two comes from the hydrochloric
acid!!!
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AJKOER
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A different approach I am planning on trying out (based on my prior experimentation with silver) requires a new investment in silver metal
(interestingly, no lab equipment needed, which also reduces ones visibility to neighbors, authorities,.., and can be performed in a home lab, not
outdoors).
First, add silver metal to vinegar, dilute H2O2 with a pinch of KNO3 as an electrolyte. Jump start the electrochemical reaction in a microwave to
avoid an inception period and to more rapidly form silver acetate which is soluble in excess acetic acid.
Separately after having created the silver acetate, add a weak acid (but not dilute HCl) to the TCCA (or more problematic here is to use chlorine
bleach, a mix of unwanted NaCl with the NaOCl) to form HOCl. Note, Chlorine bleach is industrially produced by the action of Cl2 gas on pure NaOH,
creating also NaCl with the NaOCl.
Next, add the HOCl to the AgOAc. The reaction readily creates AgClO3 and a white precipitate of AgCl. See Mellor quote and link at: http://www.sciencemadness.org/talk/viewthread.php?tid=18549 .
The reaction as:
AgOAc + HOCl = AgOCl + HOAc
where the silver hypochlorite readily breaks down:
3 AgOCl (aq) --> 2 AgCl (s) + AgClO3 (aq)
Finally, if one wants KClO3, now just add a dilute solution of KCl (or K2CO3):
AgClO3 (aq) + KCl (aq) --> AgCl (s) + KClO3 (aq)
Note, collect/save all your AgCl as by adding, say NaOH, and boiling, you get Ag2O (to further create more AgClO3 from HOCl):
NaOH + AgCl = AgOH + NaCl
2 AgOH = Ag2O (s) + H2O
Caution: I once reported on SM the accidental etching of a glass vessel (by strong NaOH) from leaving a mix of NaCl + Ag2O sitting over a period of
time, as the above two reactions are apparently reversible.
----------------------------------------
Citing my prior thread comment below:
| Quote: Originally posted by AJKOER |
Plante1999:
See my reference on Silver Chlorate formation. Here is another one:
Source: "A comprehensive treatise on inorganic and theoretical chemistry, Volume 2, by Joseph William Mellor, page 271. To quote:
"L. N. Vauquelin found that when chlorine acts on silver oxide diffused in water, a mixture of silver chloride and chlorate is formed, and it was
accordingly supposed that these same products are obtained when chlorine acts on the salts of silver. The products observed by L. N. Vauquelin were
shown by A. J. Balard to be end products, being preceded by the formation of silver hypochlorite. According to A. J. Balard, finely divided silver
immediately decomposes hypochlorous acid with the evolution of oxygen, and the formation of silver chloride. Again, if an alkali hypochlorite be
treated with silver nitrate, or if silver oxide, Ag20, suspended in water, be treated with chlorine, much heat is developed and silver chloride and
silver peroxide are precipitated while a liquid with bleaching properties is formed. The liquid is very unstable, and decomposes in a few minutes with
the separation of silver chloride and the formation of a soln. of silver chlorate which does not bleach. If an excess of chlorine be employed, all the
silver is precipitated and a soln. of hypochlorous and chloric acids remains. If an alkali hydroxide be added to the bleaching liquid, oxygen is
evolved, and a mixture of silver chloride and peroxide is precipitated. Similar results are obtained if an aq. soln. of silver chlorate, nitrate, or
acetate be employed except that the corresponding acid is liberated. J. S. Stas has •shown that probably no chloric acid or silver chlorate is
formed in the primary reaction:
Ag20+2Cl2+H20=2AgCl+2HCl0
If the silver oxide or carbonate be in excess, the silver oxide gradually forms silver hypochlorite,
2HOCl + Ag20 =2AgOCl+H20
which is readily soluble, and the soln. is stable so long as it is shaken with the excess of silver oxide present. This salt is partially decomposed
on standing in darkness, and completely decomposed at 60° into silver chloride and chlorate:
3AgOCl=2AgCl+AgCl03
and the latter remains in soln. in the alkaline liquid. J. S. Stas found no signs of the formation of perchloric acid. F. Raschig prepared silver
hypochlorite by the action of alkaline sodium hypochlorite on silver nitrate, and also by adding a soln. of silver nitrate to sodium azide, NaN3, or
to a soln. of chloroazide in sodium hydroxide."
LINK:
http://books.google.com/books?pg=PA271&lpg=PA271&dq=...
So the formation of Silver Chlorate is apparently not slow and one can actually visibly observe the formation of the AgCl. I suspect that AgClO3
should be quickly be employed in a reaction, or dried per the directions, as the aqueous solution is most likely not stable. In fact, Mellor (cited
previously), page 340, notes that AgClO3 decomposes into AgCl and O2 in the presence of HCl, HNO3 and even Acetic acid. Chlorine also reacts forming
AgCl, HClO3 and O2.
To comment on why one would not try to make AgClO3 as the soluble salt of choice is that only 1/3 of the Silver metal is converted into a soluble
salt.
In addition to the aqueous stability issue of AgClO3, the generally slow dissolution of Silver metal itself into a salt and the cost of the acids, the
main issue of say large scale production of, for example KClO3 (by adding KCl to AgClO3), remains the inherent cost of the Silver itself even with
recycling.
[Edited on 16-1-2012 by AJKOER] |
Note, per above the silver chlorate may be unstable in the presence of vinegar/acetic acid, in which case, it may be advisable to convert silver
acetate into silver oxide with the addition of NaOH before treating with HOCl.
[Edited on 26-8-2019 by AJKOER]
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Keras
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| Quote: Originally posted by AJKOER | A different approach I am planning on trying out (based on my prior experimentation with silver) requires a new investment in silver metal
(interestingly, no lab equipment needed, which also reduces ones visibility to neighbors, authorities,.., and can be performed in a home lab, not
outdoors).
|
Interesting. Isn't it possible to use a cheaper metal (nickel, iron, chromium…) instead of silver?
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AJKOER
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| Quote: Originally posted by Keras | | Quote: Originally posted by AJKOER | A different approach I am planning on trying out (based on my prior experimentation with silver) requires a new investment in silver metal
(interestingly, no lab equipment needed, which also reduces ones visibility to neighbors, authorities,.., and can be performed in a home lab, not
outdoors).
|
Interesting. Isn't it possible to use a cheaper metal (nickel, iron, chromium…) instead of silver? |
There is a source claiming in very low concentration (and near neutral pH) the following path (see my cited sources at http://www.sciencemadness.org/talk/viewthread.php?tid=151898... ):
3 HOCl --CuO --> 2 HCl + HClO3
I suspect the actual reaction is;
CuO + 2 HOCl --> H2O + Cu(OCl)2 (unstable)
3 Cu(OCl)2 + 3 H2O --> 3 CuO + 4 HCl + 2 HClO3
My attempts with this path are negative, but I did not control pH. Perhaps some chlorate could be formed in the presence of a NaHCO3 (acting as a pH
buffer).
----------------------------------------
Another possible path is based on Pb (Lead metal, toxicity issues).
A cited reaction with say Lead acetate and Chlorine Bleach creates a white precipitate of Lead hypochlorite. Heating the Pb(ClO)2 creates red PbO2
(source, please see http://bcs.whfreeman.com/WebPub/Chemistry/ichem5e/Videos/Hyp... , to quote:
"Initially, lead(II) ion reacts with hypochlorite ion to give a white precipitate of lead(II) hypochlorite:
Pb2++(aq) + 2 ClO-(aq) --> Pb(ClO)2(s) "
See my comments and references at http://www.sciencemadness.org/talk/viewthread.php?tid=62249 .
But, is it really the decomposition of Pb(OCl)2 or Pb(ClO3)2 forming the PbO2? See https://books.google.com/books?id=NkhEAQAAMAAJ&pg=PA724&... .
Idea: The creation of the white Lead hypochlorite suggests that by decanting most of the solution, one has a moist concentrated hypochlorite. As such,
perhaps try treating with CO2 (or Cl2 based on the decomposition products of AgClO3 with various acids) may release highly concentrated HOCl, which
rapidly converts, in part, to HClO3 on warming (see https://books.google.com/books?id=yVpFbnwi-aAC&pg=PA494&... ). Add a potassium salt to freeze out KClO3.
A similar approach, as I have done previously, prepare dibasic magnesium hypochlorite, a white salt that loves water which smells like aqueous NaOCl.
Try treating with CO2 (or Cl2) and warm in sunlight as a possible path to chlorate.
To quote from the cited patent (link http://ip.com/patfam/en/16863755):
"Abstract (English, JP 04108602 A) PURPOSE: To obtain basic magnesium hypochlorite useful for a germicide with high fixing rate of effective chlorine
in a short time by adding alkali metal hydroxide to an aq. mixture soln. of inorg. compd. having a hypochlorous acid group and magnesium salt.
CONSTITUTION: An inorg. compd. having a hypochlorous acid group (e.g. sodium hypochlorite) and a magnesium salt (e.g. magnesium chloride) are added to
water and mixed. Then, an alkali metal hydroxide (e.g. sodium hydroxide) is added to this aq. mixture soln. to cause reaction. The precipitated basic
magnesium hypochlorite is separated by filtering, washed with water and dried to obtain the basic magnesium hypochlorite. The proper proportion of
each source material used is 1.4-2.3mol of magnesium salt and 2-3.5mol of alkali metal hydroxide to 1mol of hypochlorous group. COPYRIGHT:
(C)1992,JPO&Japio"
[Edited on 28-8-2019 by AJKOER]
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Fantasma4500
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consider NaOH + TCCA if youre gonna Cl2 + NaOH anyways
TCCA and NaOH forms NaClO
if you absolutely must, make sure the bubbles come through with very large surface area, aquarium bubbler or homemade modification, i do recall
basically failed yields from the people who tried this whole thing, possible had a lot to do with poor absorbtion
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