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Author: Subject: questions about my chloroform
Actinium
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[*] posted on 29-10-2014 at 14:00
questions about my chloroform


I had made some chloroform via Haloform reaction of Aceton (dry) with 1L of 8.25% Sodium Hypochlorite. I have left the Chloroform in the container with some of the left over water from the post reaction, (don't ask).
I finally have some time to set my rig up and distille. I'm sure that HCL has evolved and needs neutralizing. Should I be worried about Phosgene?
would washing it with Dh20 a couple of time then washing with saturated Sodium Carbonate or Bicarbonate solution to neutralize the HCL? dry and distille and store Properly?
Or should it be properly destroyed and started over?

It was stored in the bleach bottle, in my basement where it is very cool especially this time of year and no light other than from a 60w bulb.
-Ac-
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Jylliana
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[*] posted on 29-10-2014 at 14:35


I don't think you have to worry much about Phosgene, since it's formed due to UV radiation. As long you keep the liquid away from too much sunlight, you should be fine.

I'm not sure about the HCl... maybe someone else can help you with that.




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macckone
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[*] posted on 29-10-2014 at 14:44


Sodium bicarbonate solution is used to neutralize phosgene. Ethanol will also neutralize phosgene.

Phosgene requires oxygen and light to form from chloroform.
UV light is more efficient but lower frequency light can cause the reaction as well. Without UV it is unlikely to have formed in a few days.
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Amos
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[*] posted on 30-10-2014 at 02:46


How long ago was this haloform reaction done? If it's only been a few days, you probably don't have a lot to worry about. When you said you left it with some leftover water from the reaction, do you mean some of the aqueous layer that was on top of the chloroform after the reaction? That's got NaOH in it as a product of the reaction, which will not only neutralize acid such as HCl(which really shouldn't be there at all), but probably is slowly destroying your chloroform.



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CuReUS
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[*] posted on 30-10-2014 at 04:03


Quote: Originally posted by macckone  
. Ethanol will also neutralize phosgene..

yes by forming diethyl carbonate ,but it will give HCl as a by product:(
http://en.wikipedia.org/wiki/Diethyl_carbonate



[Edited on 30-10-2014 by CuReUS]
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Actinium
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[*] posted on 30-10-2014 at 13:19


wouldn't it be better to neutralize with saturated sodium Carbonat or Bicarbonat and use ethanol to stabilize it?
Is 95%-96% ok or does it need to be anhydrous EtOH?
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aga
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[*] posted on 30-10-2014 at 14:18


Introducing Water isn't great, due to :-
1. the other side reactions that may occur (actual knowledgeable person fill in here please)
2. a Pure reagent is better to have, as you Know what is in it.

In any case you'll need to add some ethanol or an alternative (akpfihp) to neutralise any phosgene that forms.

If you do not Need the chloroform, dump it back into the reaction liquid and leave it for a week or so before flushing.

Chloroform should be prepared for Use rather than Long-Term Storage, as it decomposes over time.

A bit like making a sandwich today so you can have a packed lunch next month.

I have a bottle of 1-month old packed lunch in a drawer, and feel sure i'll have to make some fresh before use.




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Amos
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[*] posted on 30-10-2014 at 16:00


Quote: Originally posted by aga  
Introducing Water isn't great, due to :-
1. the other side reactions that may occur (actual knowledgeable person fill in here please)
2. a Pure reagent is better to have, as you Know what is in it.

In any case you'll need to add some ethanol or an alternative (akpfihp) to neutralise any phosgene that forms.

If you do not Need the chloroform, dump it back into the reaction liquid and leave it for a week or so before flushing.

Chloroform should be prepared for Use rather than Long-Term Storage, as it decomposes over time.

A bit like making a sandwich today so you can have a packed lunch next month.

I have a bottle of 1-month old packed lunch in a drawer, and feel sure i'll have to make some fresh before use.


Aga, you can keep it indefinitely, actually. You just might need to wash it with sodium bicarbonate and redistill/dry it, but that's way less work than starting from scratch again.




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[*] posted on 30-10-2014 at 20:19


This is the equation for the reaction
CH3COCH3 + 3 NaOCl => CHCl3 + CH3COONa (sodium acetate) + 2 NaOH

so, there is no need to worry about HCl.
You can even dry the CH3COONa and NaOH and perhaps figure out how to separate them.

This is my video for chloroform
https://www.youtube.com/watch?v=HtW1IfdTiB0

[Edited on 31-10-2014 by vmelkon]




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[*] posted on 30-10-2014 at 21:20


I've gotten some quite unpleasant whiffs of what I guess was minute quantities of phosgene (plus HOCl/HCl or whatever else gets generated alongside) from a clear glass bottle of chloroform (~250ml) that was sitting in a garage for a week, exposed to diffuse daylight. It didn't smell like that when I put it away. I wouldn't regard the danger as negligible if you store it without some kind of additive to neutralize the phosgene. I've since switched it to a brown glass bottle and added a bit of methanol.




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Actinium
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[*] posted on 30-10-2014 at 21:37


Quote: Originally posted by No Tears Only Dreams Now  
Quote: Originally posted by aga  
Introducing Water isn't great, due to :-
1. the other side reactions that may occur (actual knowledgeable person fill in here please)
2. a Pure reagent is better to have, as you Know what is in it.

In any case you'll need to add some ethanol or an alternative (akpfihp) to neutralise any phosgene that forms.

If you do not Need the chloroform, dump it back into the reaction liquid and leave it for a week or so before flushing.

Chloroform should be prepared for Use rather than Long-Term Storage, as it decomposes over time.

A bit like making a sandwich today so you can have a packed lunch next month.

I have a bottle of 1-month old packed lunch in a drawer, and feel sure i'll have to make some fresh before use.


Aga, you can keep it indefinitely, actually. You just might need to wash it with sodium bicarbonate and redistill/dry it, but that's way less work than starting from scratch again.

How much Sodium Bicarbonate did you use in your solution and how much of this solution did you use to wash? I can't find anythinf on this and guess its my lake of creative wording that prohibits me from succeeding.

As always, thanks guys for all the replies and imput.
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vmelkon
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[*] posted on 31-10-2014 at 03:44


Quote: Originally posted by bbartlog  
I've gotten some quite unpleasant whiffs of what I guess was minute quantities of phosgene (plus HOCl/HCl or whatever else gets generated alongside) from a clear glass bottle of chloroform (~250ml) that was sitting in a garage for a week, exposed to diffuse daylight. It didn't smell like that when I put it away. I wouldn't regard the danger as negligible if you store it without some kind of additive to neutralize the phosgene. I've since switched it to a brown glass bottle and added a bit of methanol.


What's preventing you from putting the bottle in a cardboard box, shielded from light? You can even store it in a freezer to reduce the rate of any chemical reaction.




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greenlight
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[*] posted on 5-11-2014 at 22:48


I have also heard to store the chloroform in a bottle where it can be as full as possible with almost no air gap to reduce the chance of conversion with oxygen if it is to be stored for longer periods.
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[*] posted on 6-11-2014 at 13:34


Limiting the amount of headspace at the top is also supposed to be a good idea. As for how much sodium bicarbonate, as you asked earlier, Actinium, it's not very big of a deal how much you use. Impurities, dangerous or not, are not likely to be present as a significant percentage of the liquid unless your chloroform is positively ancient, so any considerable amount (let's say you wash a liter of chloroform with 100mL of water containing 10 grams of sodium bicarbonate; that would be even more than is necessary, but would still get the job done and wouldn't involve wasting much money or sacrificing purity). Phosgene doesn't want that badly to form; chloroform vapour requires oxygen and an initiator(I think that's the right word) like sunlight to form phosgene. If you limit the light exposure and the amount of headroom for vapor formation, you're not going to cause a chemical disaster.



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