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entropy51
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Nothing, really. This reaction always tends to misbehave. You may have
added too much acetone before the reaction started. From my post above, this method works for me (most of the time). Use a large flask with good
stirring.
Quote: Originally posted by entropy51  | Chloroform
50 gm Ca(OCl)2 and 150 mL H2O was placed in a 1 Liter RBF equipped with magnetic stirring and a reflux condenser and surrounded by a cold (not ice)
water bath. 19 mL of acetone was added cautiously, first in 1 mL portions through the condenser until the mixture thickened and foamed. Add remainer
of acetone in small portions to maintain a gentle reflux without heating. Finally stir for one hour and arrange condenser for downward distillation.
Distill off the CHCl3 using a hot water bath. BP = 60 - 63 C. Yield was about 15 mL.
It is important to use an oversize flask as the reaction foams vigorously. |
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trezza
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Once all of the acetone is added and it has been stirred can I expect it to return to a liquid? The large flask I'm using to carry it out in doesn't
have a ground head so I can't use a condenser, I need to transfer the liquid over to a smaller flask for distilling when the reaction completes.
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Arthur Dent
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Well, you guys seem to have a lot of fun with this, so I decided to try this interesting experiment, and I devised an apparatus for my synthesis using
some of my newly-acquired glassware. I started with 500 ml of 6% Sodium Hypochlorite, and 10 ml of acetone, as suggested in previous posts.
Being weary of this first synthesis of a toxic compound, and knowing that it's exothermic, I took extreme precaution in setting-up my apparatus, even
putting a gas scubber on top of the setup to see if the reaction generates any gas. I decided to use a separatory funnel for two distinct uses: 1 To
slowly drip the acetone in the bleach, and 2 To separate the final solutions from each other.
This is the synthesis apparatus, I used a round bottom flask set in an ice water bath, and put the separatory funnel on top in order to drip very
slowly the acetone in the bleach solution. I dropped a small stubby stir bar in the round bottom flask and set the stirplate to medium. The
thermometer was set just to satisfy my curiosity, and see if the ice bath warms up much. The reaction started with both liquids at about 3 deg.
celcius.
carefully measured 10 ml of acetone
Pouring the acetone in the separatory funnel, and then I opened the stopcock just barely so that it was dripping about one drop per second.
In this picture, you can see the really cool swirl that started forming as each drop of acetone entered the solution.
With the bath, the slow addition of acetone and the constant swirling action of the stir bar, the reaction was quite rapid, and only slightly
exothermic, the flask was barely lukewarm even at its peak.
An then, I saw a very cool reaction... 2 minutes into the acetone addition, (1/3 of the acetone in) WOOSH! the solution turned from transparent to
cloudy almost instantly, in less than half a second! I would have missed it if it wasn't the fact that I was staring intensely at the flask!
Another change in the solution, about 6 minutes into the reaction, the solution turned from yellowish beige to a lovely opal color, and you could
notice droplets of CHCl<sub>3</sub> forming and swirling around at the bottom. Final temperature of the bath (with all the ice melted) was
about 10 deg. celcius. And as for the generated gas? Ziltch! Nada! Nutthin'! There was not even one bubble released in the gas scrubber, and my
apparatus was tightly sealed!
The reaction took barely 20 minutes total from the first drop to the coalescing of chloroform at the bottom of the flask. I disassembled the entire
apparatus and set-up the separatory funnel with a small 10 ml volumetric flask below.
I pipetted most of the solution on top with... a turkey baster! Hell of a lot faster than a 10 ml pipette! The remaining solution was poured in the
separatory funnel to separate the CHCl<sub>3</sub>
You can clearly see the clean separation between the chloroform and the remaining solution of sodium acetate, acetone and gunk.
Final yield: about 6 ml of impure chloroform. Yay! You can see the disassembled gear at the back, already cleaned and ready to be put back.
So my first synthesis of that magical product was a success. Just wanted to check if I could do it. As I was looking at the small volumetric flask, I
said to myself "Now what?" What do I do with this small amount of chloroform? Since I have no use for it for the moment and it doesn't keep very well,
I promply disposed of it. 
What helped was that I used the right gear and took my time to set-up everything. Goes to show that there's a tool for every task and when you use the
proper tools and good methodology, you get good results. And I want to thank Peach for inspiring me to post this detailed photo-description of my
experiment!
Robert
[Edited on 4-3-2011 by Arthur Dent]
--- Art is making something out of nothing and selling it. - Frank Zappa ---
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Paddywhacker
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> Now what?
Look at the chlorobutanol thread. You can condense your chloroform with more acetone to make a tertiary alcohol, chlorobutanol. Lovely transparent
crystals easily purified by sublimation, I hear.
Then you can esterify it with acetic acid to make an exotic ester, and tell us what it smells like.
Chemistry is fun.
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Arthur Dent
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Mhh, I have no use for chlorobutanol either, but as for your second suggestion, would a mixture of the two produce methyl chloroacetate?
CH<sub>3</sub>COOH + CHCl<sub>3</sub> --> C<sub>3</sub>H<sub>5</sub>ClO<sub>2</sub>
?Sorry, I'm not very well versed in the magic of Ethanoic Acid and acetates... 
Robert
--- Art is making something out of nothing and selling it. - Frank Zappa ---
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Paddywhacker
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No.
My suggestion was that you esterify the chlorobutanol to make the acetate ester. The acetate esters around the molecular weight of butyl acetate and
amyl acetate are very fruity, so the chlorobutanol acetate may be similar.
If yoy have access to other ketones than acetone, such as methyl ethyl ketone, or MIBK, these might undergo an analogous reaction to that of actone to
provide you with higher molecular weight analogues of chlorobutanol, which you could also esterify. But that is speculation on my part.
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DougTheMapper
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Well, since it seems that everybody is performing this reaction, I decided to give it a go.
Here's the setup with the 5.3L jug of 6.15% NaClO in a bucket with snow and water. Chloroform does not attack HDPE.
Acetone was added over the course of an hour in 10mL increments. The temp never exceeded 26C. Total added amount was 125mL.
The vessel was allowed to settle for 30 minutes before the majority of the effluent was decanted from the trichloromethane.
The remainder separated beautifully and was introduced to the bottle using a separatory funnel.
The final raw product is now stored in an amber bottle for further processing. I may end up using it as-is for caffeine extraction or I might distill
and dry it to get into chlorobutanol. Final yield was 110mL (±5)
Pretty routine synth. I find myself strangely attracted to the smell of the chloroform. It has a very unique sweet odor which becomes hot at higher
concentrations.
[Edited on 8-3-2011 by DougTheMapper]
Victor Grignard is a methylated spirit.
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Aqua_Fortis_100%
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Nice prep. and yields, Arthur Dent and DougTheMapper.
Im building an electrochemical chlorine generator (based on this: http://quimicanova.sbq.org.br/qn/qnol/1993/vol16n2/v16_n2_%2... (portuguese) ) in order to make some nice experiments in next hollidays..
I was wondering if direct chlorination of acetone in aqueous NaOH would produce chloroform. I know that reacting chlorine with acetone/H2O/CaCO3 one
will make treacherous chloroacetone(s), but Im not sure if high pH of NaOH is sufficient to prevent chloroacetone formation and thus making
chloroform..
If this is not possible, then would chlorinating EtOH in aqueous NaOH be an alternative?..
Thanks.
"The secret of freedom lies in educating people, whereas the secret of tyranny is in keeping them ignorant."
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simba
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| Quote: Originally posted by Aqua_Fortis_100% | Nice prep. and yields, Arthur Dent and DougTheMapper.
Im building an electrochemical chlorine generator (based on this: http://quimicanova.sbq.org.br/qn/qnol/1993/vol16n2/v16_n2_%2... (portuguese) ) in order to make some nice experiments in next hollidays..
I was wondering if direct chlorination of acetone in aqueous NaOH would produce chloroform. I know that reacting chlorine with acetone/H2O/CaCO3 one
will make treacherous chloroacetone(s), but Im not sure if high pH of NaOH is sufficient to prevent chloroacetone formation and thus making
chloroform..
If this is not possible, then would chlorinating EtOH in aqueous NaOH be an alternative?..
Thanks.
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EtOH should work. Today I made iodoform accidentally this way, I was gonna make sodium iodide from iodine tincture + NaOH. But since the tincture used
EtOH as solvent, I got iodoform instead of iodide.
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MeSynth
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If you guys are trying to get chlorform I recommend the bleach and acetone method. You get a bucket of ice and pour in a gallon of bleach that you can
buy from home depot and then add in acetone. I forget the ratio of bleach to acetone. The ice is needed for the right reaction to take place. I think
I found that method in the rhodium archive. all you do is stir it like soup until its done and the separate the chloroform layer and distil. I used my
chloroform to weld styrofoam. 
Low yeilding though.
[Edited on 4-10-2011 by MeSynth]
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Steve_hi
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I was reading this thread from the begining and someone posted that chloroform doesnt keep that well now i'm wondering about mine which I bought last
january I have a litre can of reagent grade is there anything I can do to keep it longer? how long does it take to degrade? it is in a metal can and
I have opened it.
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mr.crow
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Your chloroform will be fine. It decomposes with light and oxygen to make phosgene. Stabilizers like methanol react with this to get rid of it. Metal
can = no light
Double, double toil and trouble; Fire burn, and caldron bubble
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ScienceHideout
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I have mine in a clear- amber glass bottle (I bought it). I keep it in the darkness of my chemical cabinet... so I would think that I shouldn't worry
about phosgene.
hey, if you are reading this, I can't U2U, but you are always welcome to send me an email!
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Foss_Jeane
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Been There; Done That
This isn't all that difficult to do. The key to success is to use good hypochlorite. Clorox doesn't work, though a more concentrated form ("Liquid
Plumr" -- when it was still basically hypochlorite before they started putting other gunk in it) worked just fine. Keeping the reaction cool, and
stirring helps greatly. Add the acetone or MEK (used both) portionwise until the color is discharged. The chloroform drops to the bottom, and is drawn
off with a sep funnel. More can be distilled out of the remaining water.
The chloroform can then be distilled, dried over MgSO4, and stored with a little dry ethanol or methanol to clean up whatever phosgene forms (reacts
quickly to form ethyl or methyl carbonate). You can boil off the water to recover the sodium acetate or propionate. No sense wasting it (especially
the latter) waste not; want not.
Bad Idea #1)
"A bit soaked in paper towel and held to a flame will sizzle slightly and occasionally give off a darker smoke/vapor. I do not know if this is the
papertowel burning, or otherwise, but at one point, I sniffed lightly the fumes rising above it and was hit with an odd sensation of burning, pain,
shock, suffocation, and general"
Never do that. Burning chloroform (and other methane chlorides) makes phosgene. Not good.
Bad Idea #2)
"As far as the applications of chloroform, how much is needed to "knock out" an hypothetical human subject weighing approximately 120 pounds? How long
does it take to "kick in"? And how long until they naturally revive (assuming that they are not in the 1 of 1000 that die from it)?"
Chloroform was once used for anesthesia until it was discovered that 1 out of 4000 people would not survive. Those might seem to be pretty long odds,
but if you're wrong, you die. It's a good solvent, but breathing it isn't such a swell idea.
Bad Idea #3)
"He passed out for a few minutes, but came out alive. The good thing about HCN is that it doesn't cause long-term injury- if you recover, it's as if
nothing happened . Just make sure to get fresh air".
Actually, HCN does have long term consequences, as it turns into formic acid. It can have the same effect as drinking methanol: ruins your
eyesight, and could cause blindness. If working with HCN, a good fume hood is mandatory. If using HCN, it is also inflammable to the N-th
degree, and makes explosive mixtures with air. It's also been known to self-detonate as well.
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woelen
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| Quote: Originally posted by Steve_hi | | I was reading this thread from the begining and someone posted that chloroform doesnt keep that well now i'm wondering about mine which I bought last
january I have a litre can of reagent grade is there anything I can do to keep it longer? how long does it take to degrade? it is in a metal can and
I have opened it. |
Chloroform keeps indefinately in a perfectly closed container. It indeed reacts with
oxygen from air, making phosgene, but once that oxygen is used up no further reactions occur. So, if your bottle of chloroform is well sealed and no
air can get in, then your chloroform will keep for a very long time. Only when the bottle is opened and closed frequently it will deteriorate. For
this reason, I have put 100 ml of my chloroform in a small bottle and I use that for experiments and the remaining 400 ml I keep in the original
bottle, well sealed and this bottle is not opened, until the small 100 ml is empty.
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497
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| Quote: | Actually, HCN does have long term consequences, as it turns into formic acid. It can have the same effect as drinking methanol: ruins your eyesight,
and could cause blindness. If working with HCN, a good fume hood is mandatory.
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I don't buy it. Is there any reference that this is a serious danger from cyanide? Workers have inhaled up to 10 ppm levels of HCN every day for many
years and suffered relatively minor health effects. Levels over about 20 ppm cause noticeable physical effects such as headache immediately. Levels of
30 ppm or below are not lethal after 8 hours. 100 ppm may be lethal after 1 hour of exposure. The amount of formic acid formed from this sort of one
time exposure will never be near that of a sublethal one time methanol exposure. By the way HCN is lighter than air.
Realistically, you are either going to expose yourself levels of 100 ppm or above and risk rapid death or you will be exposed to lower levels, feel
physical symptoms, leave the area and ultimately survive. Formic acid will be the least of your worries. Nobody here is going to be exposed to the
small possible range of 20-40 ppm chronically for anywhere near long enough for formic acid to matter in the long term.
Still, I wouldn't ever think about working with it outside of a hood.
[Edited on 3-11-2011 by 497]
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bbartlog
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| Quote: Originally posted by Foss_Jeane | | Clorox doesn't work, though a more concentrated form ("Liquid Plumr" -- when it was still basically hypochlorite before they started putting other
gunk in it) worked just fine. |
Chlorox (6.15% bleach, no additives) works just fine. Granted, Chlorox also sells about a dozen other value-added forms of bleach that likely won't
work.
| Quote: | | Keeping the reaction cool, and stirring helps greatly. Add the acetone or MEK (used both) portionwise until the color is discharged. The chloroform
drops to the bottom, and is drawn off with a sep funnel. More can be distilled out of the remaining water. |
Cooling is nice but not always necessary. Start with cold reagents and use 6% bleach and you don't need to cool the reaction, though it might improve
yields. And don't use MEK... yields are much worse (I recall 22% the one time I used it), as far as I can tell the reaction doesn't proceed properly
if the non-terminal carbon adjacent to the carbonyl is chlorinated first. And what color are you talking about? Are you adding ketone on the basis of
color changes rather than measuring it? Overshooting (using too much acetone) will damage your yield.
Distilling more from the remaining water sounds good in theory but in practice is not worth it and may even yield nothing. Have you tried it?
| Quote: | | You can boil off the water to recover the sodium acetate or propionate. |
Again, I doubt you have tried this. There is so much junk (especially in the latter case) that recovering the carboxylate in usable (mostly pure) form
is a major pain. When I boiled down and evaporated a solution with the sodium acetate, it turned out to have unreacted bleach (some of which turned to
sodium chlorate) as well as other side products; acidification to try to obtain acetic acid resulted in what was probably ClO2.
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roXefeller
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So I noticed something this weekend that seems clever, if only I designed it that way. It involves stratification. So I added the acetone to 8%
bleach (dollar general is the best =) ) without previously icing the liquor. I really appreciate the already dissolved NaOCl and the very soluble
byproducts. Anyway the mixture obviously warms up. While stirring, once it warms to a good temp that the reaction proceeds nicely without boiling
the volatiles, I float the ice along the top. This sets up a nice circulation where hot products are formed midway in the vessel, rising up to the
floating ice, and finally cooling and dropping to the bottom. If the volatiles start getting boil nucleation, they are easily quenched in the ice
shield. So the reaction proceeds quickly with heat but doesn't lose product from boiling.
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