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Little_Ghost_again
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Making Bleach
This is a rerun of the experiment I did making chloroform with IPA, I still cant find answers to some of the observations I had.
So I want to try again and see why things didnt turn out as I expected.
The bleach I have is somewhat degraded but I have alot of it, so my options at the moment are to try and concentrate this bleach or make my own.
As I understand it I can make bleach by bubbling chlorine into dilute sodium hydroxide, is this correct and what kind of concentration of active
chlorine can I expect?
Is there anyway to increase the strength of the bleach I have by bubbling chlorine into it?
I am also trying a couple of other things but I will wait and see how they pan out
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hyfalcon
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Use some of that MMO I sent you with close temperature control. One of the side reactions of hypochlorite and I don't remember the temp and charge
density it must be run at that favors that side reaction but it shouldn't be to hard to find.
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deltaH
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You're not using electrolysis? If you want to use chlorine gas, then you best add sodium carbonate to the solution, else the pH will become too acidic
and you will stop dissolving chlorine. Try to keep the pH just above 12.
Also, make sure the solution doesn't get warm or you will make chlorate. Cool with ice!
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ave369
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A question for someone who tried making bleach.
How intensely does chlorine react with a concentrated alkali solution? Should I bubble the gas through it very slowly to avoid having unreacted
chlorine? Specifically I'm talking about potassium bleach as precursor to potassium ferrate.
Smells like ammonia....
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Little_Ghost_again
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Quote: Originally posted by hyfalcon  | | Use some of that MMO I sent you with close temperature control. One of the side reactions of hypochlorite and I don't remember the temp and charge
density it must be run at that favors that side reaction but it shouldn't be to hard to find. |
Ah I cant do multiple quotes!!!
I hadnt thought of electrolysis, can you expand on this a little please. I am willing to try several methods, those MMO grids have been great. I cut
two small sections off one the larger ones and they still seem to be growing strong! One is now getting a bit darker in colour in colour to the other
but still going strong  .
I chose to cut 4cm lengths so I had more if things went wrong.
I dont have sodium carbonate at the moment, I have magnesium carbonate or sodium hydroxide. I might have some sodium Bi carb but will need to go check
on that.
I know this will seem pointless but in the IPA experiment I did I added sodium Chloride and sodium Hydroxide when making the chloroform, I am
wondering what happens if you saturate the bleach with salt? I have a flask with bleach and salt in at the moment.
I know its not real science but I am trying to find out what actually happened last time
Thank you for the answers
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UC235
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Chilled sodium or potassium hydroxide solution is very effective at absorbing chlorine gas until you get close to equivalence. It's easiest to track
chlorine absorption by weight and with NaOH, 12%ish by weight is a good target. It is very exothermic from what I remember so you'll need quite a lot
of ice.
Existing bleach can be made stronger (in fact it will save you a lot of hassle and reagents to do so) by adding cooled conc. NaOH solution and adding
chlorine gas until desired weight gain. Heavily degraded bleach might end up saturated or precipitating salt though, so proceed carefully if that is a
problem. Addition of salt has basically no effect on bleach and it probably contains a fair bit anyway leftover from the electrolysis brine.
[Edited on 3-10-2015 by UC235]
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Little_Ghost_again
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| Quote: Originally posted by UC235 | Chilled sodium or potassium hydroxide solution is very effective at absorbing chlorine gas until you get close to equivalence. It's easiest to track
chlorine absorption by weight and with NaOH, 12%ish by weight is a good target. It is very exothermic from what I remember so you'll need quite a lot
of ice.
Existing bleach can be made stronger (in fact it will save you a lot of hassle and reagents to do so) by adding cooled conc. NaOH solution and adding
chlorine gas until desired weight gain. Heavily degraded bleach might end up saturated or precipitating salt though, so proceed carefully if that is a
problem. Addition of salt has basically no effect on bleach and it probably contains a fair bit anyway leftover from the electrolysis brine.
[Edited on 3-10-2015 by UC235] |
Thanks I will set this up and give it a try.
In case the chlorine generator gets out of hand and at the end of the reaction if I need to get rid of the chlorine will bubbling it into thiosulphate
get rid of it? I know thiosulphate neutralizes bleach so I am wondering is a solution of it will get rid of the chlorine?
Dont ask me, I only know enough to be dangerous
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UC235
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| Quote: Originally posted by Little_Ghost_again | | Quote: Originally posted by UC235 | Chilled sodium or potassium hydroxide solution is very effective at absorbing chlorine gas until you get close to equivalence. It's easiest to track
chlorine absorption by weight and with NaOH, 12%ish by weight is a good target. It is very exothermic from what I remember so you'll need quite a lot
of ice.
Existing bleach can be made stronger (in fact it will save you a lot of hassle and reagents to do so) by adding cooled conc. NaOH solution and adding
chlorine gas until desired weight gain. Heavily degraded bleach might end up saturated or precipitating salt though, so proceed carefully if that is a
problem. Addition of salt has basically no effect on bleach and it probably contains a fair bit anyway leftover from the electrolysis brine.
[Edited on 3-10-2015 by UC235] |
Thanks I will set this up and give it a try.
In case the chlorine generator gets out of hand and at the end of the reaction if I need to get rid of the chlorine will bubbling it into thiosulphate
get rid of it? I know thiosulphate neutralizes bleach so I am wondering is a solution of it will get rid of the chlorine? |
Thiosulfate would work, but the path of least resistance is easiest. Use an inverted funnel over some more dilute NaOH solution as a scrubber.
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deltaH
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Interestingly, chlorine passed through ice cold water precipitates transparent crystals of a chlorine hydrate. According to attached paper, it has an
empirical formula of 6Cl2.46H2O.
This is easily reversed and the crystals effervesce chlorine when thawed.
I wonder if the chlorine hydrate can first be prepared by bubbling chlorine straight into a snow/crushed ice slush, decanting, then slowly and
carefully adding alkali solution to this with cooling to make a really concentrated bleach.
I see this is something best done in winter
Attachment: chlorine hydrate structure.pdf (701kB)
This file has been downloaded 422 times
[Edited on 3-10-2015 by deltaH]
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Little_Ghost_again
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| Quote: Originally posted by UC235 | | Quote: Originally posted by Little_Ghost_again | | Quote: Originally posted by UC235 | Chilled sodium or potassium hydroxide solution is very effective at absorbing chlorine gas until you get close to equivalence. It's easiest to track
chlorine absorption by weight and with NaOH, 12%ish by weight is a good target. It is very exothermic from what I remember so you'll need quite a lot
of ice.
Existing bleach can be made stronger (in fact it will save you a lot of hassle and reagents to do so) by adding cooled conc. NaOH solution and adding
chlorine gas until desired weight gain. Heavily degraded bleach might end up saturated or precipitating salt though, so proceed carefully if that is a
problem. Addition of salt has basically no effect on bleach and it probably contains a fair bit anyway leftover from the electrolysis brine.
[Edited on 3-10-2015 by UC235] |
Thanks I will set this up and give it a try.
In case the chlorine generator gets out of hand and at the end of the reaction if I need to get rid of the chlorine will bubbling it into thiosulphate
get rid of it? I know thiosulphate neutralizes bleach so I am wondering is a solution of it will get rid of the chlorine? |
Thiosulfate would work, but the path of least resistance is easiest. Use an inverted funnel over some more dilute NaOH solution as a scrubber.
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Yes a much better idea!! I will be using an aquarium pump to push the chlorine left in the reaction vessel out, as I dont have a fume hood at the
moment I was looking for a way to empty the reaction vessel of chlorine, never occurred to me to just make a weak bleach with the excess gas.
Its late now and I have lost the light so will continue this in the morning.
Delta H thats got to be worth a try , I might give this a go after I have tried
the other ways. I have some ice made with sodium chloride I could crush, its reading -18 on the IR thermometer so I might try this, I use milk bottles
filled with saturated salt solution then frozen for cooling water in buckets etc, I have several of these so might try this out
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deltaH
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Well the nice thing of first forming the chlorine hydrate is that you knock out the heat of fusion and the hydrate itself melting has a heat of
fusion, so all this makes for much better temperature management when you add the NaOH, plus the chlorine is about as concentrated as you could get
it, short of working with liquid chlorine.
But be prepared that the hydrate may decide to thermally run away and vent all its chlorine in one go! PRECAUTIONS! PRECAUTIONS! PRECAUTIONS!
A gas mask with ability to absorb chlorine would be a good idea!
[Edited on 3-10-2015 by deltaH]
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Little_Ghost_again
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Just as a side thought, seeing as I have a lot of hydroxide prills and no sodium carbonate, I take it I can just leave some the hydroxide prills out
and wait for them to dry out again, i take it this way I should be left with sodium carbonate. Or I guess I could just bubble co2 into prills that
have turned liquid in air.
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Little_Ghost_again
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In the morning I will post some pics of my set up, if it looks ok I will give it a go and try for the hydrate. No gas mask but I can do it outside.
I will probably leave some of the ice water with the hydrate and drip the hydroxide into that, it might help with keeping it cool, if I can find a big
enough container I will fill that with crushed ice as well
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deltaH
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It's wise to work on a small scale first. I suspect it's not that easy to form the hydrate.
I'd fill a small flask with finely crushed ice and lead in the delivery tube from the chlorine generator and then for good measure, put the ice
containing flask in a bucket of ice slurry, but I wouldn't salt it.
I don't know what you're using for a chlorine generator, but I'd use just enough there so that it can be started and then get well away while it's
delivering the chlorine. When it's all done, you can approach it again, but make sure the flask is sitting in a bucket of ice slurry at all times,
else chlorine will start evolving rapidly!
My gut feeling is that salted ice might mess things up. I'd just work with ice slurry at 0C.
I strongly suggest you try to get a gas mask, even if working outside. It just takes the weight off one's shoulder.
In the second step, I'd slowly add the sodium hydroxide while swirling and cooling in the ice-slurry bucket. This stage is where I think you really
need a gas mask because you will be near the chlorine!
If chlorine starts venting, immediately move away far upwind!
I wouldn't use carbonate if using the chlorine hydrates, just sodium hydroxide solution.
You will be targeting a pH of a little over 12 eventually. This is the pH of regular bleach, not sure if it's a good pH for a concentrated bleach?
[Edited on 3-10-2015 by deltaH]
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Little_Ghost_again
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I will have a look and see if I can use an addition funnel and maybe use something like a 3 neck flask. that way if chlorine does evolve it can be
scrubbed. I prefer to try and avoid it getting out in the first place .
The mask i have definitely isnt upto chlorine, I will see what I can rig and if it isnt adequate then I will wait until I can get a mask.
I need another fume cupboard really, but that isnt going to be soon.
I really appreciate the help. The salt bath I will use just for cooling, I will go make some plain ice now so its ready for the morning.
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deltaH
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Working with chlorine hydrates is just a hypothetical alternative, but I love to look for new and possibly better ways to do things. If all else
fails, simply bubbling chlorine into chilled alkali will work.
[Edited on 3-10-2015 by deltaH]
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Little_Ghost_again
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| Quote: Originally posted by deltaH | Working with chlorine hydrates is just a hypothetical alternative, but I love to look for new and possibly better ways to do things. If all else
fails, simply bubbling chlorine into chilled alkali will work.
[Edited on 3-10-2015 by deltaH] |
I will try both ways, I use Chloroform for some extractions so finding a way to make stronger bleach or even making a decently strong bleach would be
good. No harm in trying it out!!
What is the theoretical limit to the strength of the bleach using hydrates?
If it works the being able to make Chloroform using less liquid makes the whole thing easier, at the moment I use a 15 ltr carboy and pouring off the
solution to get to the small amount of chloroform is a bit of a pain.
I am wondering if you could use IPA with sodium hydroxide and then bubble the chlorine in, but thats probably pushing it lol. Contrary to popular
belief I do experiment a fair bit, but I am not great at maths and working out formulas I find hard, so I dont post most of the things I do as it
makes me look stupid when I cant do the working out and formula stuff.
I also have an update for the iodine thread, I cant get pics until the morning but I had a couple of surprises
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Bot0nist
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Off topic.
LGa, have you tried the haloform using OTC bleach and acetone? A few of us had moderate success in this thread. Is Isopropyl just much easier to find or cheaper to use for you.
Using a 15gal carboy would be hell to cool properly, is that hurting your yeilds. You should post a chloroform writeup, in that thread, or elsewere.
I'm curious of the reaction conditions and yeild.
[Edited on 3-10-2015 by Bot0nist]
U.T.F.S.E. and learn the joys of autodidacticism!
Don't judge each day only by the harvest you reap, but also by the seeds you sow.
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deltaH
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Theoretically, let's say you isolate 6Cl2.42H2O and remove all excess water. Then let's say you add 50% sodium hydroxide solution on a weight basis,
on a mole basis, that 1 NaOH to 2.2 H2O.
Cl2 + 2NaOH => NaClO + NaCl + H2O
6Cl2.42H2O + 12NaOH + 26.4H2O => 6NaClO + 6NaCl + 284.4H2O
That's 7.5% NaClO on a weight basis... so not that high.
[Edited on 3-10-2015 by deltaH]
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Little_Ghost_again
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| Quote: Originally posted by Bot0nist | Off topic.
LGa, have you tried the haloform using OTC bleach and acetone? A few of us had moderate success in this thread. Is Isopropyl just much easier to find or cheaper to use for you.
Using a 15gal carboy would be hell to cool properly, is that hurting your yeilds. You should post a chloroform writeup, in that thread, or elsewere.
I'm curious of the reaction conditions and yeild.
[Edited on 3-10-2015 by Bot0nist] |
I have a couple of old threads I did on it on here, I will see if I can find them. IPA was what I had at the time and I found very little in the way
of temperature rise. I cant remember off hand but I am sure in the thread I noted it was only 3 or 4c rise (I think???).
This thread is actually about another attempt at making Chloroform with IPA, last time I observed a few things I just couldnt understand as i added
salt and sodium hydroxide and didnt measure much, this time I want to do it and measure everything. I used IPA because I had alot of it at the time,
looking at others yield maybe mine wasnt so bad after all. One thing for sure if I had removed the Chloroform earlier then I would have had much more,
it wasnt the temperature I think it was the amount of sodium hydroxide I added.
But bare with me this thread will turn into a chloroform write up, I am trying first to see if I can increase my bleach strength. The bleach I got was
20 ltr but its sat for a while and seeing as it cost me £21 I want to use it
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Little_Ghost_again
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one of the other chloroform threads I did was this one http://www.sciencemadness.org/talk/viewthread.php?tid=33930
its crap and I am sure I messed up the temperatures, looking back aga was right about the IR thermometers, so I wouldnt rely on the temps I gave. what
I can tell you is the solution barely got warm, certainly less warm than I normally get mixing hydroxide with water, but that itself seems a bit odd.
Anyway this attempt will be documented better, i am interested in one of the by products i got because i couldnt find out what it was.
It proved to be a great solvent though
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hyfalcon
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Download the pdf at the bottom of the thread LG. Good read.
http://www.sciencemadness.org/talk/viewthread.php?tid=43266
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AJKOER
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Here is a form of solid bleach from one of my prior threads, "Preparation/Exploration of Mg(ClO)2.2Mg(OH)2, a Solid Hypochlorite", at https://www.sciencemadness.org/whisper/viewthread.php?tid=26... that you may find of value.
Not strong enough? You may try treating the moist compound with chlorine (which I have not tried) with the intended goal of the monobasic magnesium
hypochlorite, sometimes described as Mg(OH)OCl, as the pure magnesium hypochlorite apparently does not exist (see, for example, discussion at https://en.m.wikipedia.org/wiki/Hypochlorite .
[Edited on 4-10-2015 by AJKOER]
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Little_Ghost_again
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Thanks I will start reading, not had a great start this morning, suggestions for chlorine generation? I would prefer a solid and drip a liquid onto
it, guess which one I have tried so far  . 7.5% is less than I can buy, I would like
to aim for 15%+ is that going to be possible? Having said that if I add the hydrate to the bleach then maybe it will help as the bleach is used up. I
better go read instead of just guessing.
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Little_Ghost_again
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that is a good read, I will get bogged down if I try too much at once. So plan is to stick to the hydrate first, then try the others one by one using
IPA. I figure we should find a decent way to make chloroform with IPA and a way to make the bleach strong. Yes I know people use acetone but I did
have some good results with IPA and I would like to see where it goes.
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