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Amos
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Quote: Originally posted by Little_Ghost_again  | UPDATE
Temperature risen to 28.9c (all temps taken with IR temp gun). I have a 2 Ltr conical flask with a cotton wool stopper.
Flask gently swirled 4-5 times, stopper removed and contents sniffed (wafted). Strange smell............ IPA I would describe as a Blunt/rough kind of
smell and very distinctive, this smell from the flask dosnt smell like chloroform (yet) and no droplets of chloroform are visible, however the smell
has a much more sweet/sickly smell that I would describe as aromatic and lingering, it leaves a taste in the back of the throat for a fairly long time
>10 mins.
Smells volatile and unlike IPA is apparent as soon as the flask is opened.
While I am pretty sure this will give chloroform in the end, I want to redo tomorrow and remove a few more unknowns. For example the hydroxide liquid
is a few days old and is simply sodium hydroxide prills that have reacted with the air, no water has been added intentionally.
So I have no idea of the composition of this liquid and no idea of concentration etc.
Tomorrow when I repeat I will use dry prills and make a solution (molar strength undecided at this point) .
I would really appreciate some help tomorrow in working out what reactions are taking place and what the end products are likely to be. Apart from the
target compound (Chloroform) I am interested if anything else can be extracted from the liquid that is decanted from the Chloroform.
I am reading up on equations etc but at present I am at a very early stage in understanding. I know this amount of hand holding is a PITA, but it
would be really appreciated  .
I dont need it for this current experiment, this was more to do with seeing if I could repeat last nights.
I am also looking into how I can calculate the strength of hypochlorite as it is, in its current form.
It is a fascinating process, I am surprised at the lack of heat, I would have expected far more, even if purely from adding hydroxide. If I can get
this working correctly and a decent yield then for me its a better way than Acetone. It also seems to not require any form of temperature control (so
far). |
Okay, I did warn you about this before, but now that you're working with such large amounts of your reactants, you need to be cautious about how much
chloroform vapor you allow into the air and how long you leave these things out. Oxygen and light will convert it to phosgene, which is amongst the
biggest hazards you can encounter in a home chemistry setting(as far as I know, anyway).
As for you, Actinium, my first couple of haloform reactions were not all that precise(I might've even measured by eye the amount of acetone to use
without even weighing it) and there wasn't a huge jump in the amount of chloroform I got when I started being more serious with my calculations.
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Little_Ghost_again
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| Quote: Originally posted by No Tears Only Dreams Now | | Quote: Originally posted by Little_Ghost_again | UPDATE
Temperature risen to 28.9c (all temps taken with IR temp gun). I have a 2 Ltr conical flask with a cotton wool stopper.
Flask gently swirled 4-5 times, stopper removed and contents sniffed (wafted). Strange smell............ IPA I would describe as a Blunt/rough kind of
smell and very distinctive, this smell from the flask dosnt smell like chloroform (yet) and no droplets of chloroform are visible, however the smell
has a much more sweet/sickly smell that I would describe as aromatic and lingering, it leaves a taste in the back of the throat for a fairly long time
>10 mins.
Smells volatile and unlike IPA is apparent as soon as the flask is opened.
While I am pretty sure this will give chloroform in the end, I want to redo tomorrow and remove a few more unknowns. For example the hydroxide liquid
is a few days old and is simply sodium hydroxide prills that have reacted with the air, no water has been added intentionally.
So I have no idea of the composition of this liquid and no idea of concentration etc.
Tomorrow when I repeat I will use dry prills and make a solution (molar strength undecided at this point) .
I would really appreciate some help tomorrow in working out what reactions are taking place and what the end products are likely to be. Apart from the
target compound (Chloroform) I am interested if anything else can be extracted from the liquid that is decanted from the Chloroform.
I am reading up on equations etc but at present I am at a very early stage in understanding. I know this amount of hand holding is a PITA, but it
would be really appreciated .
I dont need it for this current experiment, this was more to do with seeing if I could repeat last nights.
I am also looking into how I can calculate the strength of hypochlorite as it is, in its current form.
It is a fascinating process, I am surprised at the lack of heat, I would have expected far more, even if purely from adding hydroxide. If I can get
this working correctly and a decent yield then for me its a better way than Acetone. It also seems to not require any form of temperature control (so
far). |
Okay, I did warn you about this before, but now that you're working with such large amounts of your reactants, you need to be cautious about how much
chloroform vapor you allow into the air and how long you leave these things out. Oxygen and light will convert it to phosgene, which is amongst the
biggest hazards you can encounter in a home chemistry setting(as far as I know, anyway).
As for you, Actinium, my first couple of haloform reactions were not all that precise(I might've even measured by eye the amount of acetone to use
without even weighing it) and there wasn't a huge jump in the amount of chloroform I got when I started being more serious with my calculations.
|
The flask is now sealed, I will weigh the product from this batch and dispose (it isnt a huge yield).
I currently have more questions than answers!
For example
Because we had the referendum in Scotland last night, everyone stayed up until 4am. During that time the flask started to loose the yellow tinge and
star to clear, there was some chloroform in the flask so I added 100g of hypochlorite. I could see chloroform begin to bead and form straight away.
Temperature was 31c in flask and 13c in room. I Added another 50g of hypochlorite before bed and again chloroform appeared to drop out almost straight
away.
This morning the solution has gone a slightly cloudy very pale milk like colour, temp of flask 18.9c, room 15c.No yellow tinge, so added 20g
hypochlorite.
not much happening and certainly no chloroform dropping straight out. SoI am guessing reaction is about done.
I will leave until 4pm when I get in from School. Then separate to measure Chloroform, I am guessing roughly 80ml from just over 2 ltr of solution.
Yield not great on one hand but then again I dont actually know starting concentration of this batch, I am pretty sure it had degraded.
I would like to see if I can some measure the concentration of hypochlorite in the tub. My gut feeling is the concentration is going to be a lot lower
than the 10% it was meant to be.
In that case the yield would be pretty good, I havnt used much IPA in this reaction so, I will be trying again soon. I will wait until I have some
Ethanol and amber reagent bottle to store the chloroform in.
If when I get home the solution is milky clear again then I will decant off and mess with that . I am interested in what it might contain.
Its definitely worth doing again, the reaction never went above 33c even starting from room temp solutions, no cooling at all used or needed. A very
small amount of solvent used (Under a Ltr).
So how do I titrate the contents on the bleach barrel? only acids I have are citric and vinegar! I can order some and some indicator solution.
I am guessing I make a 1M solution of Acid and titrate say 100ml of bleach until end point, then calculate (will read all this up first) from there.
If all the hypochlorate has been used up and all the IPA then what products are likely to be left?
If its salt then I would try and recover some (no reason, just something I want to try).
BUT none of this will happen until I have an idea of what reactions likely took place and what I am likely to have left over in the waste solution.
How long roughly before phosgene etc is likely to be a problem? If its >24hours then I will wait until later tonight to dispose of. While at School
the flask is sealed with clear food rap and elastic band (seems to have cause a very slight vacuum). Flask will be put into a cupboard.
EXCEPT
I have forgotten its friday so home by 11am today .
Anyway for safety this project will put on the back burner until I have more info and better storage etc .
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Little_Ghost_again
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Ok had a few problems sorting it out lol.
Anyway I ended up with 110ml !! its really strange stuff, kind of sticks to the sides of glassware even in a liquid, then as soon as another blob
touches it they fall to the bottom! turn the sep funnel upside down once or twice and it all falls to the bottom!
Anyway looks like it worked for sure!!! So as soon as my Ethanol is ready and my amber bottles are here I will make some more . I can get IPA a fair bit cheaper than acetone so that will be handy!
Havnt had the heart to clear up yet  . But I guess for safety better I get rid for
now.
So for now thats the end of my experiment, but I will come back to this one again 
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Amos
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I was going to tell you that you could try stabilizing chloroform with isopropanol instead of ethanol and just keeping it out of sunlight. My
container(it is amber glass) is kept pretty full to keep gas from building up on top, just in case the IPA doesn't work. Someone that has experience
with chloroform or with the chemistry of stabilizing it: Could one use isopropanol instead of ethanol? Phosgene is supposed to decompose in the
presence of "alcohols" (that's all it says), so I'd assume it would work.
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Little_Ghost_again
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Its ok its all gone now, I wanted to try and see if I could use IPA and get a decent yield. I am happy that I can do that, I want to find the strength
of the hypochlorite as the yield was actually a lot higher than I expected. I also dont understand how it can work so well and yet produce so little
heat.
Anyway I will be doing it again soon and my Ethanol will be ready to distill soon.
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Little_Ghost_again
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I thought that was the end of it!
I kept back the waste water from the reaction, the idea being once I had the knowledge to work out the reactions that had taken place I would know
what was in it.
I couldnt resist trying things out though...................... So yesterday I added 230 ml of it to a sep funnel and added a pinch of table salt. I
did this because as the pics show the waste is cloudy, I wondered if salt would cause anything to drop out of make the solution clearer.
This morning I have a layer at the top of clear liquid, there is around 50-60ml. I have no idea (yet) what it is, the smell is similar to IPA but not
exactly, so it could be an azeotrope of the IPA I used and water from the reaction, but that dosnt make much sense, I didnt use much IPA so I am
surprised there is so much of this after I got a good yield of Chloroform.
I will leave this another 24 hours then separate. Some of it I will put in a flask and maybe add sodium hydroxide, the idea being to see if I can draw
any water out of it.
Some I will distill and see what temperature the distillate comes out over. First I will see if there is any sodium hydroxide in it because I dont
want to distill and freeze and joints! So I will test a little with some acid.
I might even have a go at adding citric acid to some in a flask then distill it and see what comes over.
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byko3y
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I've tried to make chloroform (after failing to produce acetone) using OTC NaOCl solution.
I've measured NaOCl content to be 1.8%, but I doubt it contains only the hypochlorite.
So, I took a flask with 300 ml of this solution, which is slightly green, and slowly poured few ml of isopropanol. Nothing happened, so I though it's
a good idea to add 5g of NaOH to it.
Still nothing happened, the solution remained slightly green and had an odor of IPA. Then I heated it for unknown amount of time (less than hour), and
later on distillation I got my IPa back (maybe there's some chloroform in it). In the source flask I noticed some precipitate, and went like "wtf,
there should be not precipitate".
I really think my hypochlorite is not a hypochlorite in fact, because when I tried to acidify it, the smell of chlorine was really horrible, though it
might have been not a Cl2.
Left - solution before heating, pale green color. Right - solution after heating and filtering off a white precipitate, totaly colorless.
I think the precipitate is NaCl, old hypochlorite solutions contain a lot of it.
I measured NaOCl amount via titration with acidified HI, then a free iodine was titrated with Na2S3O3.
Normal reaction is
NaOCl + 2 HI ==> I2 + NaCl + H2O
I can suggest that the solution contained a lot of chlorate. It can give a lot of chlorine by the reaction
NaClO3 + 6 HCl ==> 3 Cl2 + 3 H2O + NaCl
While the reaction with chlorate might go like
NaOCl3 + HI ==> NaIO3 + HCl
without giving a free iodine, and there's a limited amount of iodine in the solution, so maybe the iodate was not able to oxidize hydrogen iodide into
iodine, but instead gave off a free chlorine.
There could be a chlorite in the solution, or whatever, I have no other ideas.
Is there any way to measure amount of chlorate in hypochlorite solution?
Maybe I could try to regenerate the hypochlorite, is there any easy way except evaporating the free chlorine and absorbing it with NaOH solution?
UPD: tried to heat the hypochlorite solution to boiling point. I think that color of IPA+hypochlorite solution turned yellow-green after heating -
this is the color I've got after heating a pure hypochlorite. And then, when the temperature is approx 90°C, some strange thing started to happen on
boiling stones and on the whole surface of liquid-glass contact: smole bubbles are generated, which don't look like a boiling water, but rather some
decomposition generating oxygen (chlorate decomposition?). This process generates the precipitate I mentioned above. But this time the solution
remains yellow even after reaching the boiling point of water, unlike IPA+NaOCl which turns colorless.
Addition of a small amount of NaOH doesn't change anything.
[Edited on 29-4-2015 by byko3y]
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