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ballzofsteel
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sulfuric
Alternatively,you could mix salt with your TCCA and drip sulfuric onto it.
Wouldnt this eliminate the need for drying.
The H2SO4 would release chlorine and absorb water,whilst forming HCl at the same time,which in turn would release more Cl2 and so on.
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guy
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can MgSO4 be used for drying chlorine?
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The_Davster
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If it is anhydrous and not the heptahydrate, I would assume so.
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Organikum
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When you drop conc. H2SO4 onto a mixture of NaCl and TCCA you will get a mixture of Cl2 and HCl gas.
This idea was lately dicussed at the HIVE brought up by a busy bee who has obviously fallen in love with TCCA.
There is no practical way to come around the drying steps in chlorine production I believe. Usually CaCl2 is used as first step and H2SO4 as second
to dry chlorine. MgSO4 or CaCl2 alone wont get the Cl2 real dry - of course it depends on what you want to do with it if this suffices or not.
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Theoretic
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"Hypochlorites and mineral acids produces very well chlorine."
How?
2NaClO + H2SO4 => Na2SO4 + 2HClO.
If hydrochloric acid is used, it will work.
Another possibility is if HClO decomposes and the resulting HCl reacts with more HClO. But that would use twice as much hypochlorite and contaminate
the chlorine produced with oxygen.
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Organikum
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Theoretic you suggested:
2NaClO + H2SO4 => Na2SO4 + 2HClO
May I suggest:
4NaClO + 2H2SO4 => 2Na2SO4 + 2H2O +2Cl2
edit: I corrected the equatation after trilobite told me that I forgot something...
The prove is in the pudding. Add some H2SO4 to bleach and you will see it by yourself.
I dont want to annoy you by quoting 19th century textbooks where I discovered this method first times ago....
[Edited on 1-7-2004 by Organikum]
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trilobite
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Decomposition of hypochlorous acid
The first equation is correct in the sense that hypochlorous acid is indeed a species existing in acidic aqueous solutions of hypochlorite, but that
doesn't mean hypochlorous acid is stable. The latter equation isn't balanced correctly, two chlorine atoms are missing from the right side.
The truth is that hypochlorite disproportionates in acidic solutions to chlorine and perchlorate as hypochlorous acid gets oxidised by hypochlorite
ions. Here are the half -reactions and the whole equation for you.
| Code: | 12ClO- + 12H+ + 12e- ---> 6Cl2 + 12H2O E= 1.63V
2ClO- + 6H2O ---> 2ClO4- + 12H+ + 12e- E=-1.38V
-----------------------------------------------------------
14ClO- + 12H+ ---> 6Cl2 + 2ClO4- + 6H2O E= 0.25V
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Or in other words, so that the role of hypochlorous acid becomes obvious:
| Code: | 12HClO- + 12e- ---> 6Cl2 + 12H2O E= 1.63V
2ClO- + 6H2O ---> 2ClO4- + 12H+ + 12e- E=-1.38V
-----------------------------------------------------
12HClO + 2ClO- ---> 6Cl2 + 2ClO4- + 6H2O E= 0.25V |
Also, when chlorine is dissolved in water or aqueous sodium hydroxide, the following happens
| Code: | Cl2 + H2O <---> HOCl + HCl |
So the function of the sodium hydroxide is in fact solvate the hypochlorous acid by neutralizing the acids shifting the equilibrium to right and
preventing the decomposition. However, no perchlorate would be formed in those conditions as those chloride ions are left in the solution.
| Code: | 2ClO4- + 12Cl- + 8H+ ---> 7Cl2 + 8H2O |
Thus, if one wanted to make chlorine from pure solid hypochlorites, he might want to add some chloride salts too.
[Edited on 1-7-2004 by trilobite]
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Chemtastic
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| Quote: |
Reacting hypochlorites with acids would get you HClO and not Cl2. Mix in an equimolar amount of NaCl to your hypochlorite and use twice as much acid,
that will work.
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So you would recommend 1 mole of Ca(OCl)2 to every 1 mole of NaCl to every 2 moles of the acid used, Theoretic?
Also, no one ever answered my question about drying the Cl2 produced. Wouldn't it be possible by either lowering the temperature below 0C and
removing the ice or lowering the temperature below -35C and removing the liquid Cl2?
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unionised
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Chlorine will tend to form the hydrate under those conditions (ie cold and wet).
MgSO4, CaCl2or H2SO4 or quite a lot of other things can be used to dry chlorine.
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Organikum
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Just use HCl and TCCA or a hypochlorite. Wetten your calcium hypochlorite before dropping diluted HCl on it. Dropping concentrated HCl will liberate
shitloads of HCl with the Cl2.
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Chemtastic
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Hmmm...
I never knew that gases had hydrated forms...
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Proteios
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loads of gases form hydrates....clatherates.....methane, SO2, all the noble gases. The conditions are usually kinda quirky, but gases forming
hydrates is not uncommon. SO2 is somewhat different in that it will both react with water, and form clatherates. I dunno about Cl2, but see no real
problem in this forming clatherates too.
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Theoretic
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"May I suggest:
4NaClO + 2H2SO4 => 2Na2SO4 + 2H2O +2Cl2
edit: I corrected the equatation after trilobite told me that I forgot something..."
Oh no. You've corrected it and it's still unbalanced! Two oxygen atoms are missing from the right side of the equation.
"The prove is in the pudding. Add some H2SO4 to bleach and you will see it by yourself."
True, this is because bleach also contains NaCl.
"I dont want to annoy you by quoting 19th century textbooks where I discovered this method first times ago...."
Well, the textbooks apparently said so because the disproportionation of HClO by hypochlorite happens.
Hold on... Perchloric acid!?! Can someone please provide details? Rate, optimal temperature, side reactions?
"So you would recommend 1 mole of Ca(OCl)2 to every 1 mole of NaCl to every 2 moles of the acid used, Theoretic?"
What I meant is 1 mole of chloride ions to 1 mole of hypochlorite ions. 1 mole of Ca(ClO)2 compound, two moles of NaCl and one mole of H2SO4.
"Also, no one ever answered my question about drying the Cl2 produced. Wouldn't it be possible by either lowering the temperature below 0C
and removing the ice or lowering the temperature below -35C and removing the liquid Cl2?"
Well, you could use the CaSO4/ CaCl2/Na2SO4/NaCl mixture you made when producing chlorine . You could use anhydrous CaSO4 or CaCl2.
[Edited on 3-7-2004 by Theoretic]
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hodges
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| Quote: | Originally posted by Theoretic
"May I suggest:
4NaClO + 2H2SO4 => 2Na2SO4 + 2H2O +2Cl2
edit: I corrected the equatation after trilobite told me that I forgot something..."
Oh no. You've corrected it and it's still unbalanced! Two oxygen atoms are missing from the right side of the equation.
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I've seen a discussion of this reaction in Usenet before, although I don't remember where. As I recall, some O2 is also produced by the
reaction, as well as the Cl2. Commercial bleach is made by bubbling chlorine through NaOH and thus contains NaCl as well as NaOCl. Thus when you
acidify regular bleach you don't get any oxygen, because of the extra chloride. Also I don't believe NaOCl is very stable by itself so in
practice its usually going to be mixed with NaCl.
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kryss
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Trilobite your getting mixed up hypochlorite disproportioates into chlorate not perchlorate! Hence if you heat a given quantity of bleach you get one
third of its equivalent as chlorate, the rest as chloride.
Then if you go on to melt the solid chlorate if further disproportates into perchlorate and chloride.
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Theoretic
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Kryss, it is true that hypochlorites disproportionate into chloride and chlorate BY THEMSELVES, but molecular hypochlorous acid has properties WAY
different from the hypochlorite ion, so that reaction has the right to differ. 
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S.C. Wack
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Not much different:
5HClO = HClO3 + 4HCl + O2 or
3HClO = HClO3 + 2HCl and
HCl + HClO = H2O + Cl2
2HClO = 2HCl + O2
6HClO + NaCl = NaClO3 + Cl2 + 3H2O
A quote from Cotton and Wilkinson:
"In general, the chemistry of these acids [halogen oxo acids] and their salts is very complicated."
Yes hypochlorous acid can be made from bleaching powder with HNO3, HCl, and best with boric acid, but there are problems as you see. And not in
equimolar amounts, even in very dilute solution: 4NaClO + 4HCl = 4NaCl + 2Cl2 + O2 + 2H2O
It looks like CO2 is a strong enough acid to give Cl: 2Ca(ClO)2 + 2CO2 = 2CaCO3 + 2Cl2 + O2.
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chemoleo
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On that note - ever wondered why calcium hypochlorite still smells of chlorine? Is it because of the CO2 reacting with it? I bet the only way to get
Ca(OCl)2 stable is to keep it under vacuum....
Never Stop to Begin, and Never Begin to Stop...
Tolerance is good. But not with the intolerant! (Wilhelm Busch)
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Pyrovus
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Commerical Ca(OCl)2 generally comes in a hydrated form, so the chlorine smell might come partly from interaction between the water of hydration and
the hypochlorite ions:
OCl- + H2O <-> HOCl + OH-
With subsequent decomposition of the HOCl.
Never accept that which can be changed.
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kryss
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Kryss, it is true that hypochlorites disproportionate into chloride and chlorate BY THEMSELVES, but molecular hypochlorous acid has properties WAY
different from the hypochlorite ion, so that reaction has the right to differ.
Ordinary bleach is stabler in alkaline solution but slowly goes off, especially in sunlight.
Hypochlorite solution as in pure NaOCL is less stable and more light senstive.
I think this is all tied into the amount of HClO present as it is light sensitive (UV) and heat sensitive.
I think 3OCl ->ClO3 + 2Cl-
Although you lose chlorine you keep all its oxidising power.
For HCLO its different:
HClO -> HCl + 0.5 O2
and
HClO + HCl ->Cl2 +H2O
I have read that an azetrope can be distilled off under vacuum, think you need to distill HgO with OCl- - might be Chlorine monoxide though.
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Michal
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I have just recieved my order form the pottery store, and I wanted to try and make Cl2.
I used MnO2 and HCl 10% sol.
I added a little bit of MnO2 in a reaction tube, and added the HCl sol.
But nothing happend, there was nog smell of chlorine at all 
What do you people think is the problem ?
Is 10% HCl to weak to produce chlorine from MnO2 ?
Maby I added to mutch HCl beqause it was a HCl/MnO2 solution, not a powder with a few drops of HCl.
Also, I used my MnO2 straight from the bag, maby it has to be activated with a weak HCl solution ?
If you use HCl it will oxidise the Cl<sup>-</sup> to Cl2, so would'nt NaCl solution work ?
Thx for your time to read these questions 
Edit: Hurray, finaly there was a smell of chlorine, but not really strong (if I smelled 5cm away from the reaction tube) it smelled the same like 5%
NaOCl solution.
When heated the smell became stronger
Will KMnO4 work better in producing chlorine ? But I will propably stick to my MnO2 beqause it's dirt cheap -> 1kg = 1,92 euro
[Edited on 11-7-2004 by Michal]
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Reverend Necroticus Rex
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I never had much success using MnO2 to release Cl from HCl, KMnO4 does a brilliant job of liberating chlorine, so much so that it's a good idea
to be careful as to how much you add, I make ALL my chlorine gas this way
The sun is shining on a brand new day
Blackened corpses burn where they were slain
Self-flagellation prompts him to confess, Bless me father, for I made this mess.
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Organikum
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MnO2 and HCl produce chlorine mainly upon soft heating. This is actually the advantage of the method, you can get a constant stream of chlorine this
way and have no instant Cl2 outbreak upon addition.
The HCl added to the MnO2 should bo between 15% and 20% in concentration. To low a concentration can produce explosions in the worst case (its not
very probable but it has happened). More than 20% will give you lots of HCl-gas togehter with the Cl2 as the Cl2 produced will drive it out. The MnO2
used has to be wettened with water before putting it in the reaction vessel.
ORG
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Chemtastic
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Acid-Hypochlorite
As recommended to me a few weeks ago, I finally got around to trying the method on Meglomania's website, using calcium hypochlorite and sodium
bisulfate. It worked REALLY well, even at room temperature and without too much of either reactant. The biggest benefit was finding both reactants
in crystalline form. This meant they could be mixed with no reaction, forming the deadliest "just add water" mix I've ever used.
I did get an interesting repeat of results. Using a glass jar with a screw on lid, I filled it up with water, then added an equimolar (approximately)
quantity of each reactant, quickly screwing the lid on. Chlorine gas bubbled vigorously, and the solution became quite warm. The vapor above the
solution became quite green.
The solution itself seperated into two layers. A gunky, white precipitate settled to the bottom, leaving a pale green (and CLEAR) supernatent. I
don't know what the white gunk is, but could it be Ca(OH)2? The green fluid I think is Cl2 dissolved in water. This was the same color as the
vinegar and bleach experiment from before, and it shared another similarity. After some time in the sunlight, it similarly changed in color from pale
green to pale red. What color is HClO in solution, since Cl2 + H2O --> HClO + HCl, and HCl is clear? Also, if anyone knows the reaction between
sodium bisulfate and calcium hypochlorite, what is it?
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guy
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The white precipitate is probably Calcium sulfate which is only moderately soluble.
[Edited on 25-7-2004 by guy]
[Edited on 25-7-2004 by guy]
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