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Haggis
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First, you used too much hypochlorite.
To extract the chloroform, you could distill it out. Another way would be to add large amounts of water to dissolve the hypochlorite. Add, stir,
decant, repeat. Eventually, you will have the chloroform sitting on the bottom. At this point, it can by placed in a seperatory funnel, and let the
chloroform droplets settle out, and seperate.
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The_Davster
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Too much hypochlorite? hmm did I do the stoich wrong?
2CH3COCH3 + 3Ca(OCl)2--> 2CHCl3 + 2Ca(OH)2+(CH3COO)2Ca -btw it was not 41g of pure calcium hypochlorite, it was 41g of 65% hypochlorite, so 26.1g
of actual hypochlorite. I started the calculation for how much hypochlorite to use from 10 mL acetone(d=0.707). The problem was not separating the
chloroform from unreacted hypochlorite but from the insoluble calcium hydroxide.
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BromicAcid
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To seperate your Ca(OH)2 the solution is simple, acidify, mix in HCl till all your Ca(OH)2 goes away.
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Hermes_Trismegistus
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Step by step!
| Quote: | Originally posted by rogue chemist
. But unfortunatly the chloroform is stuck in that layer of calcium hydroxide .
How can I get it out?  .
[Edited on 18-4-2004 by rogue chemist] |
It sounds like you have a mixture of three compounds here. Hypochlorite/mostly water.........CaOH.........CHCl3
so first decant off the Water/hypo until you have a layer of chloroform with hydroxide precipitate.
Now, place your product into a taller/thinner vessel, batch size dependent. If you are working microscale, use a test tube, if you have more, use a
grad. cyl. or a champagne flute, or whatever is handy.
Now "centrifuge" , if you have a test tube with a stopper and a lip you can swing it around on a string (just don't go too fast) if you
are using something else then just hold it in your hand at the end of your arm in the 6'oclock postition and gently swing back and forth from 4
o'clock to 8 o'clock position for a couple minutes while watching the boob tube.
If it settles on top, eyedropper it off, if it settles on bottom, eyedropper the product off. If you don't have an eyedropper...pick one up.
P.S. I've never used the Bleaching powder Method personally, But I know that with other hypochlorite's it does take about an hour and a half
for the big bead of chloroform to settle out at the bottom of the reaction vessel eh! longer if you have it at room temperature (but I assumed you
knew that and had already let it sit for that initial settling stage and were still having problems)
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The_Davster
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Thanks Hermes, I did let it settle out in ice water for about an hour. I also have about 2 dozen eyedroppers(thanks to an ordering mishap). But at
least this gives me an excuse to build a homemade centrifuge
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Darkfire
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I just did this with household bleach and acetone, Now i used 945ml of bleach and 25ml acetone. its been 1.5 hours now. I have athin clear layer on
top, which seems to be water, then a cloudy not milky whiteish layer, and then a white ppt on bottom, no chcl3 what did i do wrong here?
edit been 30 mintues, now theres no layers just one big volume of clear liquid, the reaction did take place, as from yellowy to milky then to clear...
edit been antoher 30, i poured the liquid into a baggy and the white ppt stayed in the jar, i took a wif of the ppt and a ml or 2 of remaining liquid
and it was a sweet smell that reminded me of chloropicrin a bit, sweat, clean, and strong. I took several big wifs and i got no sign of any
incapassitation.(sp)
Pics are here http://darkfire.myftp.org/fun/chemistry/chloroform/ , the finsihed amount was the bottom few mls of the baggy, but it wasnt chloroform...
[Edited on 6-6-2004 by Darkfire]
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will seek knowledge from those wiser and teach those who wish to learn from me.\" Duane Allman
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Haggis
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I have also noticed the product will differ depending on what your bleach source is. Some bleach yeilds easy to see yeilds, while others give sparkly
white foamy like yeilds.
Here is my trick when you have the latter of the two. Suck it up in a pipet or get it in a buret. The bubbles will rise to the top, and the
chloroform will sink, you can the seperate the two.
I have not discovered what exactly causes that, but I assume that it is an additive to the bleach that is present in only some brands.
My rule of thumb is to buy the cheapest bleach you can find. It won't have any fancy sufactants or the like, but will be as close to pure
hypochlorite as you can get from bleach.
Chloroform should smell thick, heavy, sweet. I have always thought it was pleasant and relaxing. I pity you if it smells like chloropicrin though,
but I can somewhat see where you are coming from, but without the stinging 'spike' that the odor of chloropicrin has.
Rinse out the jar with the suspect chloroform with water, then pour into a vessel so that you can see the chloroform layer on the bottom. If you have
any yeild, it should be in here, as you noted you didn't get any from the portion you poured out.
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Darkfire
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What do u think that white ppt was? Its only reminisent of chloropicrin, its did smell pleasent and sweet, i think i made some but it just didnt work
out. Could my ratio of bleach to acetone be the problem?
[Edited on 7-6-2004 by Darkfire]
\"I love being alive and will be the best man I possibly can. I will take love wherever I find it and offer it to everyone who will take it. I
will seek knowledge from those wiser and teach those who wish to learn from me.\" Duane Allman
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thunderfvck
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Darkfire, how did you add the acetone to the bleach? Slowly? Was the bleach cold? Perhaps the higher temperature could account for some other product
formation but I've never noticed anything like this. It's most certainly an additional something that the makers of your bleach had put in.
And I don't think the ratio of acetone:bleach has any significance on other products being formed.
Anddddddddd....!
Forgive me if this has been asked before but why does the solution turn milky white and then clear up? This is concerning the NaOCl reaction pathway.
Someone had responded to this question earlier in another thread and had said it was chloroform. But I don't really think that's
correct...since the chloroform is certainly there after the reaction is done and the solution is clear. So what gives?
The products are sodium acetate, water, chloroform, hydroxide...Am I missing something here? Does the sodium acetate have trouble dissolving at first,
or something, and this is what causes the white color? Is there some kind of transition state that <i>slowly</i> goes to completion?
And one more!
NaOCl + H2O --> HOCl + OH
HOCl + CH3COCH3 --> CHCl3 + 3H2O
Is this what is actually happening towards the formation of chloroform?
Thanks!
[Edited on 7-6-2004 by thunderfvck]
[Edited on 7-6-2004 by thunderfvck]
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The_Davster
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thunderfvck: I think the reason it turnes white is because that is the chloroform forming everywhere in the solution and then settles out and the
solution becomes clear again. As for the yellowish color I am taking a guess, It is when there is chloroform and bleach in the mix making it appear
yellow, but once all the bleach has reacted, the mix turns white. And your question about the actual reaction I believe was answered in the first or
secong pages of this thread.
[Edited on 7-6-2004 by rogue chemist]
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Darkfire
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The reason why the ratio is important is explained earlyer on in this thread. I slowly added the acetone to iced bleach.
\"I love being alive and will be the best man I possibly can. I will take love wherever I find it and offer it to everyone who will take it. I
will seek knowledge from those wiser and teach those who wish to learn from me.\" Duane Allman
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thunderfvck
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Thanks for your reply.
Yes, I noticed that the reaction was answered. But BromicAcid (I believe it was him) mentioned NaOCl. I want to know if it's in fact HOCl
that's reacting.
I am still not comfortable with the answer you've given with regards to the white color. Chloroform is clear, and so is the NaOCl solution
(mostly anyway). Neither are opaque yet it reaches a point where it is totally white. Why would the chloroform appear to be white?
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BromicAcid
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Solution is white due to chloroform microbubbles. Take for example oil and water, shake them together enough and they emulsify with some help. The
chloroform is being formed by the molecule so it is basically precipitating from a colloidal solution that it is making on the spot, as the
microspheres touch and grow larger they begin to precipitate but during the "White" stage it is the refraction across the surface of
infinite very very tiny bubbles that clouds the solution.
As for whether it is HOCl or NaOCl that does the reaction I use NaOCl as my example because it saves some typing work, in solution it is going to go
to NaOH and HOCl due to HOCl being such a weak acid and it therefore accounts for the base necessary for a haloform reaction. Pages on the haloform
reaction:
Chapter 18: Haloform reaction
CHAPTER IV
The second link has a very nice illustration of the haloform reaction halfway down the paper with HOCl as the halogenating agent, I'm sure you
could figure out the exact stoichiometry from this figure no problem.
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S.C. Wack
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First the other thread and then Darkfire's 1st post above. So I figure that one can't have too much chloroform, and I go out and buy some
bleach. Might as well post it then. Some things have changed since I last did this. Bleach has gone from 5.25 to 6%, the 10% is everywhere, and I have
a mag stirrer. So I should get better results this time, right?
When I got up I took the 3 quart jug out of the fridge, weighed, and transferred. The reactor was a gallon HDPE vinegar jug. Got it stirring and added
half of the calculated amount of acetone all at once, then put the lid on. The lid would pop off if there was too much pressure but this was not a
problem, as the bleach was cold.
It got warm/not hot anyways, but the point is that no acetone or chloroform was lost. Stirring was continued until it cooled to around room temp, a
couple hours. An impressive amount of precipitate, which I didn't separate. Back in the fridge, then this was repeated with the other half. This
was not so exothermic, and stirring continued until it warmed to room temp. Shaking produced no reaction. The precipitate was separated and distilled.
The non-chloroform part was meanwhile boiled down to 800 ml. Very little chloroform boiled out, and except for that little bit, there was no smell of
acetone, hypochlorite, or anything else. Analysis of the salts will have to wait. Gas, CO2 I hope, is and has been evolving from the cold
solution/salt crud.
The yield was only 37.47%, 34.9g. (~23ml). No leftover hypo. No leftover acetone. So where's the missing chloroform? I'm going to try this
again despite the low yield, being more careful, because this pisses me off.
The figures:
1:3 molar ratio acetone/NaOCl
3 quarts (2839ml) shurfine reg. bleach, $0.88, says 6%, assumed exact %.
Actual volume- 2875ml. Actual wt.- 2904g.
Which means that I assumed I was working with 2.3406771 moles hypo.
So 45.3g. (~58ml.) acetone was used.
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BromicAcid
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| Quote: |
Actual volume- 2875ml. Actual wt.- 2904g.
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Chloroform solubility, roughly 0.8 g / 100 ml H2O
2875/100 = 28.75 x 0.81 = 23.23 g CHCl3 left in solution.
Adding that to your yield of 34.9 g you now have a yield of roughly 62% not to mention that CHCl3 solubility might be augmented by basic environments
and that NaOCl decomposes readily on store shelves and is of questionable purity. A yield of 62% is not anything to scoff at, possibly you could
precipitate the CHCl3 in solution with the addition of another solvent to decrease solubility even more. Or using a more concentrated hypochlorite
solution would decrease the amount of solvent and increase product.
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BromicAcid
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I did some experimentation today. Tried the electrolysis of a NaCl (aq) solution with acetone to see if I could get CHCl3 via an in situ reaction.
Trial #1
Anode : Nickel
Cathode : Graphite
125 ml Acetone
100 ml H2O
25 g NaCl
None of the amounts of reagents had any premeditation. Just threw everything together as much as I hate to admit it. However it was my intention to
have the graphite as the anode because it is more resilient to Cl2, however in a later run I found that I had the anode and cathode switched.
Magnetic stirring was used as was a battery charger at 12 V, current varied from 3 A to 5 A throughout the reaction.
Initially the solution was clear to be expected. An excess of salt remained at the bottom. Soon though the solution took on a green hue but not too
dark and remained at about the same intensity for the next 10 minutes. Gasses were of course generated at the anode and cathode regardless of
magnetic stirring. To compensate for this and possibly increase initial Cl2 absorption I added about 4 g NaOH post initiation. Ten or fifteen
minutes later I turned off the stirring to check on things. The solution immediately separated into two layers. A green layer at the bottom and a clear layer at the top. There is no way enough current had gone into the solution to convert the
excess of acetone to chloroform and the NaCl present was no where near enough. I turned on the stirring again and let the solution continue on its
way for another 10 minutes then turned it off and set to the side.
After allowing to cool, I put it into a sepratory funnel and it separated easily. I separated out the bottom portion and added to a separate beaker.
I was wondering what it was, I figured it was water saturated with NiCl2 which had made it insoluble in the acetone but I needed a test. To
distinguish between H2O and acetone I did an easy test, took the Bp of it. The boiling point was 59 C. So it was not water, but this did not help to
distinguish between chloroform (61C) and acetone (56C). I needed another quick test. So I laid out some of the bottom liquid on a watch glass and
tossed a match in it. Figured that a high percentage of acetone would be flammable. However the match sizzled and went out. Another met the same
fate and another and another, finally I took one and laid the end in the mixture where it was soaked into the cardboard, as it burned down it made
wisps of white smoke unlike when coaxed to burn on their own. Therefore results were inconclusive, I believe a combination of factors were at work,
also chloroform is miscible with acetone, possibly only a small percentage of CHCl3 is necessary to precipitate acetone and also to inhibit its
burning. More tests are necessary.
Test #2
Cathode : Carbon
Anode : Nickel
75 ml Acetone
150 ml H2O
25 g NaBr
Same setup with constant stirring. Similar results except in this case I could see the Br2 being generated at the nickel anode so I swapped them,
oops. The graphite anode immediately started turning the solution black from flaking off. Or so I thought because as soon as stirring was begun
again the color disappeared mostly. Br2 was constantly coming off the anode and swirled to the middle where it disappeared, presumably meeting the
OH- from the cathode. This was continued for in upwards of 25 minutes, but after stirring was discontinued there was absolutely no precipitate [Ahhhhhh!!!!! Bromoacetone burns!!!!]
Trial #3
Anode : Graphite
Cathode : Nickel
100 ml Acetone
100 ml H2O
25 g NaCl
Realizing the error of my ways I ran this experiment again with the anode and cathode the way they should be to prevent erroneous side reactions.
Electrolysis was continued for 25 minutes with stirring at 12 V with the current fluctuating between 1 and 2 A. After electrolysis was discontinued
the solution was left to stand. A precipitate started to come out of solution, on closer inspection it appeared to be just the salt that I had in
excess at the beginning of the experiment No color change, no hint of chloroform.
So, I'm not totally sure what I've for left from my first reaction. Test for acetone next I guess, I bet the formation of acetone peroxide
might be used as a test. Test for chloroform. Odd that the results were so quick and promenade. Anyone else try this yet?
[Edited on 6/14/2004 by BromicAcid]
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menchaca
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i´m not sure at all but i think i´ve found another way to get chloroform otc.
i made it by accident when i was trying to synth hydroquinone from p-dichlorobenzene mothballs.
I dissolved the mothballs in acetone and slowly added a solution NaOH in water. Then an oily and milky liquid closely similar to chloroform appeard in
the bottom of the flask.
i think the reaction was this:
3C6H4Cl2 + CH3COCH3 + NaOH---> CHCl3 + CH3COONa + C6H5Cl
Is this correct? i know it has its own thread but i think i didn´t explain fine in the first post.
anyway i think is a possible wat to synth chloroform so it isnt out of thread.
Irepeated the experiment but now whith the ratios of the reaction above:
300ml of acetone(just the acetone enougt todissolve the mothballs)
75grs pdcb(0.5mol)
20grs NaOH in 100ml water(o.5mol)
after dissolving the mothballs, addedslowly the NaOH solution and get again the oily liquid about 100ml .
If this reaction is correct could be an interesting way of chloroform and chlorobenzene otc isn´it?
How can i test it? Thanks!!
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The_Davster
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Seems to make sense but just a little balancing error. 3C6H4Cl2 + CH3COCH3 + NaOH---> CHCl3 + CH3COONa + 3C6H5Cl
I will try this if I can find some p-dichlorobenzene mothballs
And as for testing for chloroform, there is the obvious  (though not a good idea
if you are not sure it is chloroform), or you could try a chlorobutanol synth with what you think is chloroform.
[Edited on 14-6-2004 by rogue chemist]
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Geomancer
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I wouldn't think that pDCB is active with regard to nucleophilic substitution under normal conditions (high pressure/temperature change things).
If it was, the nucleophile would probably be OH-, though, giving the phenol, and Cl- would leave; you still wouldn't get chloroform. Have you
positively ruled out the possibility that no signifigant reaction at all is happening, and the system just separates into two phases, one with
acetone/pDCB, and one with water, NaOH, and the rest of the acetone? See what happens if you use NaCl instead of NaOH.
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menchaca
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ok i´ll try with NaCl instead of NaOH and i´ll post it
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The_Davster
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Wow, the sodium hypochlorite reaction behaves much differently with a higher concentration of sodium hypochlorite. I got ahold of some 10.8% from
canadian tire. The flask goes instantly milky(localized) when even the smallest ammout of acetone is initially added. If too much acetone it
introduced to the flask at once or if the flask is not well cooled and stirred, localized boiling ensues instantaneously. With doubling hypochlorite concentration the yield doubles.
500mL 5.25% bleach+ 10mL acetone= 4mL yield
250mL 10.8% hypochlorite +10mL acetone= 8mL yield
I think I could have gotten a better yield from the 10.8% if I had used better cooling but some experimenting by adding some of the acetone too fast
probally lowered my yield.
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The_Davster
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I went into MERCK and the reaction for calcium hypochlorite is actually
2CH3COCH3+ 6Ca(OCl)2.H2O --> 2CHCl3 +Ca(CH3COO)2 +2Ca(OH)2 + 3CaCl2+ 6H2O
Is the reaction using sodium hypochlorite(from earlier in this thread) still correct?
[Edited on 5-7-2004 by rogue chemist]
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menchaca
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well snif.. you were right geomancer it wasn´t a chemical reaction.
I repeated the experiment but instead f NaOH i used NaCl solution and i got the same result a oily milky liquid in the bottom of the flask
so you are right no reaction just two phases of liquid
what a pity!! it just seemed so beautyful
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Organikum
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Reaction of bleach aka sodium hypochlorite with acetone:
CH3-CO-CH3 + 3NaOCl = CH3-CO-CCl3 + 3NaOH
CH3-CO-CCl3 + NaOH = CH3-CO-ONa + HCCl3
This is straight from Vogel´s 3rd and can be considered as correct.
(if it was already posted here then I apologize for the redundance)
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Polverone
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para-dichlorobenzene, continued
p-DCB is supposed to react with aqueous ammonia in the presence of copper, but only at elevated temperature/pressure. I've tried quite a few
things to see if I can provoke it into reacting under more easily achieved conditions. Stirring/heating with alcoholic KOH? No. Stirring/heating with
strong NaOH solution? No. Stirring/heating with strong NaOH and PTC? No. Boiling it with alcoholic AgNO3? No. Boiling it with copper sulfate and
household aqueous ammonia? No. Dropping it onto molten KOH? No. Stirring it with methanol and aluminum amalgam? No.
On the bright side, it appears that p-DCB is a relatively high-BP solvent, inert to many reagents. Too bad it sublimes so easily.
Hmm. Refluxing with molten sulfur? I might have to give that a try...
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