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chemchem
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chloroacetone
hello all !! Been searcking for a simple method one could produce chloroacetone with chlorine gas. Ive seen a method in a post once that simply
bubbled chlorine gas into chilled acetone untill fully saturated. Then distiliation could seperate the un reacted acetone from the much higher boiling
chloroacetone. My feelings are this method could produce more unsymdichloroacetone than desired product? I know the two are easily seperated <
Hopefully anhydrous and low temp conditions will be enough to banish this dreaded bi product ?? What do we think ??
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hodges
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| Quote: | Originally posted by Mendeleev
Chloroacetone [1]
Good method of preperation 150 ml acetone 50 ml water 12 g Cupric chloride 6 g lithium chloride. Reflux till reaction completes. Literature states 24
hours but the reaction has a half-life of about 24 minutes at 20°C (same article half of marker in 24 minutes, the marker being oxygen consumption in
a slightly different reaction), therefore 5 hours is probably sufficient at reflux.
After reacting, distill everything below 123°C. The still bottoms can be reprocessed to recover cuprous chloride and lithium chloride. Both can be
recovered by disolving with minimum water. The mix is easily converted to cupric chloride-lithium chloride by boiling with 20-35% hydrochloric acid.
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I realize this is an old thread but I just ran across it while looking for information on reactions with acetone. I would be curious as to what the
reaction is. Presumably the copper (II) chloride is reduced to copper (I) chloride by one of the hydrogens in the acetone, as the acetone is
converted to chloroacetone. But what purpose would the lithium chloride serve? Why not just use copper (II) chloride by itself?
Hodges
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Nicodem
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| Quote: | | But what purpose would the lithium chloride serve? Why not just use copper (II) chloride by itself? |
I would guess the purpose of LiCl is to catalyse the limiting step of the reaction, the enolisation of acetone (since LiCl is a relatively strong
Lewis acid). It might also help by increasing chloride concentration thus stabilizing the Cu2Cl2 by complexing it to [CuCl2](-) (this should lower the
transition state vs. product energy difference).
When CuBr2 is used there is no need for any such catalyst, but then again CuBr2 is in the 2CuBr2 <-> 2CuBr + Br2 equilibrium already at room
temperature so obviously there is no need to increase its reactivity or catalyse the enolisation step.
…there is a human touch of the cultist “believer” in every theorist that he must struggle against as being
unworthy of the scientist. Some of the greatest men of science have publicly repudiated a theory which earlier they hotly defended. In this lies their
scientific temper, not in the scientific defense of the theory. - Weston La Barre (Ghost Dance, 1972)
Read the The ScienceMadness Guidelines!
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Organikum
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| Quote: |
Why not just use copper (II) chloride by itself?
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Works, but is terrible slow.
/ORG
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nb198
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When I tried to distill off my chloroacetone, I was left with a black sludge in the boiling flask. Any idea what it is? The solution going into the
distillation was clear and yellow (from cl2 i assumed). No idea where the blackness came from. The sludge is also heavier than water and sinks right
to the bottom if some is added to a beaker of water.
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nb198
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Chloroacetone - Distillation lead to black death
I carried out the procedure as per Organikum and everything went well. I just needed to do the workup. I unfortunately had to do it over 3 days and I
forgot to cover the flask with tinfoil, so it kind of yellowed by the time i was able to do the distillation.
The distillation seemed to be going well. I did a simple distillation. The acetone came off with only a minor amount of chloroacetone present. I
tested this using concentrated NaOH. The acetone/chloroacetone prior to distillation resulted in a dark crimson color immediately upon addition. The
acetone distillate require a few minutes to produce a faint red color, indicating to me that the concentration of chloroacetone was much lower.
The chloroacetone seemed to come off okay and I got a yield of about 20 mL which was very low, but acceptable. However, I was left near the end of the
distillation with a dark black death that was insoluble in water and appeared to be miscible in acetone. I didn't distill until it was dry and left
about 20ml of the chloroacetone in the death liquid.
Here is what it looked like near the end of the distillation
http://i.imgur.com/XDQWGNU.jpg
What was it? Is it the polymerized chloroacetone that was concentrated from my yellowed chloroacetone mixture? I was afraid to distill it to dryness
so I just stopped the distillation and killed the black death with a load of 25M NaOH.
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Nicodem
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Threads Merged
16-3-2014 at 13:14 |
Metacelsus
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Ah yes, the famous aldol tar . . .
The tar is formed by polymerization of acetone / chloroacetone.
I ran into much the same problem while trying to produce chloroacetone by electrolysis of a mixture of acetone and hydrochloric acid (forming chlorine
in situ). I made the mistake of distilling nearly to dryness. The stuff is horrible to clean off glassware, and still possesses considerable
lachrymatory power.
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nb198
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Quote: Originally posted by Cheddite Cheese  | Ah yes, the famous aldol tar . . .
The tar is formed by polymerization of acetone / chloroacetone.
I ran into much the same problem while trying to produce chloroacetone by electrolysis of a mixture of acetone and hydrochloric acid (forming chlorine
in situ). I made the mistake of distilling nearly to dryness. The stuff is horrible to clean off glassware, and still possesses considerable
lachrymatory power. |
How do you prevent it from happening? I had to leave the acetone/chloroacetone for 2 days in the fumehood before distillation and in the
sunlight(absentmindedly). Do you think it yellowed because of this and formed tar? Would distilling it immediately after filtering/synthesis reduce
the formation of the tar? Is the tar dangerous or relatively inert after killing with naoh?
I'm thinking of doing it again, except only make like 2ml. I could probably do it in like 4-5 hours max. I would like to avoid the tar though.
[Edited on 16-3-2014 by nb198]
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Metacelsus
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You can prevent it by removing residual acid (with sodium bicarbonate) and keeping it cold. Distilling it immediately would help. I don't know how
dangerous the tar is after treatment with hydroxide.
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nb198
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| Quote: Originally posted by Cheddite Cheese | | You can prevent it by removing residual acid (with sodium bicarbonate) and keeping it cold. Distilling it immediately would help. I don't know how
dangerous the tar is after treatment with hydroxide. |
I removed residual acids using the chalk like Organikum said to. I think ultimately I left it out for what amounts to like 2 days in the sunlight...I
really feel like that is what ruined it.
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macckone
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Don't use sodium bicarbonate. It can form side products.
Don't ask me why sodium bicarbonate forms side products and
calcium carbonate (chalk) does not. I suspect it is because of the
much higher pH.
The usual methods of stabilization are neutralizing with calcium
carbonate. And then if storing, add calcium carbonate or water to the
mixture. I believe the recommended amount is 1% by weight.
Generally in chlorination reactions there are polychlorinated products
and they can be more reactive than the monochlorinated products.
For distilling chloroacetone, one trick is to distill the acetone off,
then add water which forms a constant boiling mixture (89C).
This reduces the likelihood of polychlorinated products coming over.
Based on the procedure that started the thread there is
polychlorinated acetone in there.
After distilling over the water-chloroacetone mix, you can separate
it my using salt and a seperatory funnel.
Also be careful with this stuff. It is a war gas for a reason.
*edited based on polychlorination from procedure.*
[Edited on 17-3-2014 by macckone]
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nb198
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| Quote: Originally posted by macckone | Don't use sodium bicarbonate. It can form side products.
Don't ask me why sodium bicarbonate forms side products and
calcium carbonate (chalk) does not. I suspect it is because of the
much higher pH.
The usual methods of stabilization are neutralizing with calcium
carbonate. And then if storing, add calcium carbonate or water to the
mixture. I believe the recommended amount is 1% by weight.
Generally in chlorination reactions there are polychlorinated products
and they can be more reactive than the monochlorinated products.
For distilling chloroacetone, one trick is to distill the acetone off,
then add water which forms a constant boiling mixture (89C).
This reduces the likelihood of polychlorinated products coming over.
Based on the procedure that started the thread there is
polychlorinated acetone in there.
After distilling over the water-chloroacetone mix, you can separate
it my using salt and a seperatory funnel.
Also be careful with this stuff. It is a war gas for a reason.
*edited based on polychlorination from procedure.*
[Edited on 17-3-2014 by macckone] |
Thanks! Ill try that out the next time I do it
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Mush
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Raman spectra of aliphatic chlorine compounds: IV. Chloroketones and chloroacid chlorides (pages 1409–1428)
Recueil des Travaux Chimiques des Pays-Bas
1955 Volume 74, Issue 11
H. Gerding and H. G. Haring
10.1002/recl.19550741109
"Monochloroacetone
Following Fritsch (9), it was tried to prepare pure monochloroacetone by chlorination of acetone in the presence of marble and water. Initially, only
mixtures of mono- and dichloroacetone were obtained, which could not be separated by fractional
distlllatlon owing to their small difference in boiling point. It was found that by changing the reaction conditions in various ways, viz. by
maintaining a large
excess of acetone - e.g. 5 parts of acetone and 1 part of marble and carrying out the chlorination slowly, at 5-10 C. until about one-third of the
marble has been consumed, spectroscopically pure samples of CH2Cl.CO.CH3, are obtained (i.e. no Raman lines of CHCl2.Co.CH3, could be
detected) (19)."
(9) P. Pritsch, Ber. 26, 597 (1893) Ueber die Chlorirung des Acetons
DOI: 10.1002/cber.189302601125
English translation can be found here:
http://chemistry.mdma.ch/hiveboard/chemistrydiscourse/000505318.html
Original source:
The war gases, chemistry and analysis, 1939
Attachment: 10.1002_cber.189302601125 P. Pritsch, Ber. 26, 597 (1893).pdf (109kB)
This file has been downloaded 691 times
Attachment: Recueil des Travaux Chimiques des Pays-Bas; vol. 74 (1955) p. 1409,1416.pdf (981kB)
This file has been downloaded 728 times
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Assured Fish
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Quick question
I realize this is an old thread but i could not find the answer to this question anywhere, why is it that chloroacetone undergoes an aldol
condensation when treated with NaOH however bromo and iodoacetone undergo substitution?
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Metacelsus
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Substitution and aldol condensation are probably competing reactions. Bromide and iodide are better leaving groups than chloride, so the substitution
will be faster for bromo- and iodoacetone. Therefore, a much smaller amount of those compounds will undergo aldol condensation.
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Doped-Al2O3-fusion
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Sorry to resurrect an old thread, but I'm really glad I found it. I was trying to find out what substance I accidentally made yesterday during
electrolytic recovery of copper and finally came to the conclusion it must be chloroacetone. It began with a drying step since I was trying to avoid
yield loss of elemental copper to copper oxide(s). I used acetone to rinse the copper and at some point grabbed the beaker with the rinse by mistake
and added it back into the copper chloride solution. On my next run of electrolysis, I developed these small crystals in solution which I assumed to
be a chloride salt because I had added sodium chloride into the solution earlier on.
I vacuum filtered the solution to remove the salt using a fritted glass Buckner funnel. As I scraped the salt out, it appeared to look like small
crystals of elemental silver, which I knew couldn't be the case, but it looked just like it. Confused, I examined a sample under my microscope and it
was composed of trigonal clear crystals and what appeared to be a lot of dark colored contaminates, which presumably was copper. I went back down to
my work area and noticed the rest of the sample began to turn a yellowish color. It was sitting under my overhead full spectrum florescent light.--I
mention this because this is what prompted me to believe I was on the right track as the wiki article stated this compound to be light sensitive and
turns yellow-amber. I don't have a sense of smell, so I couldn't detect any pungent odors. I'm guessing the copper chloride could have catalyzed the
reaction during electrolysis.
The copper powder itself shortly turns a purplish color hue upon exposure to the air. If placed quickly into a beaker of full strength acetone, the
solution turns murky blue and the copper settles to the bottom looking like copper powder, but I'm positive it's not pure copper powder. I performed
a number of small tests and using stannous chloride on a small amount turns the copper into a bright copper color, but after rinsing it off and
exposing it to air to dry, it eventually does the same thing. Adding this solid into a beaker of distilled water is where things became really weird
to me. The solution quickly turned cloudy blue, then yellow and finally a yellow-orange color. My eyes did get a bit irritated despite having such a
small quantity of sample test solution and mild air flow through the room.
I still don't know what the crystals were, as I only find mention that this compound is a liquid, but I assume it can form crystals. Mine were fairly
water insoluble and they eventually turn into a yellow-amber color as they oxidize (the sample on the microscope slide eventually changed color as
well). I'm also not sure what to do with the remainder of the copper chloride solution, but I'm most likely to add sodium hydroxide to it. The
percentage of acetone is about 10% of the solution at this point. It's definitely an annoying mistake as I'm really not wanting more waste solution
to have to store for the immediate future.
I'm more likely to die doing what I love. I'm a hobby chemist. I void warranties.
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RedDwarf
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I found this thread when searching for some info after viewing nile red's (nb198 I assume?) video on chloroacetone synthesis. I've got two questions
if anyone can help:
1) What's the beautiful red compound formed when chloroacetone is added to NaOH?
2) I thought most blackboard chalk was Calcium Sulfate, not Calcium Carbonate, so which is being added to the product (I'm assuming you want the
carbonate to neutralise the HCl as the sulfate wouldn't have any effect or have I missed something?)
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Metacelsus
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1) What's the beautiful red compound formed when chloroacetone is added to NaOH?
From experience: a mess of aldol condensation products.
2) I thought most blackboard chalk was Calcium Sulfate, not Calcium Carbonate, so which is being added to the product (I'm assuming you want the
carbonate to neutralise the HCl as the sulfate wouldn't have any effect or have I missed something?)
You are correct. Most blackboard "chalk" is gypsum (calcium sulfate dihydrate). But real chalk (the mineral) is calcium carbonate.
[Edited on 2019-11-26 by Metacelsus]
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S.C. Wack
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It appears that the making of chalk for chalkboards as it was in my youth is a lost art unknown to the Chinese, and it's very popular to write
internet articles saying that chalk isn't chalk, even though much of the chalk sold on amazon clearly says is made of CaCO3. And stuff.
If crushed marble is recommended by real chemists of yesteryear, it would probably not be unwise to use crushed marble, yes? Likewise the directions
specifically insist on no yellowness.
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