Sciencemadness Discussion Board

chloroform formation without distillation

nitroboy - 21-5-2004 at 03:45

i had read a synth on for chloroform and it required the use of a distillation setup (which i didn't have) so i checked out on chemfinder that trichloromethane has a low solubility and a low boiling point.
so from this i deduced that the Ca(OCl)2 (i use 75% Ca(OCl)2 powder and i make my own solution up which always leaves a powder that just wont dissolve) + Acetone method would be fine, and the heat produced on reaction would be enough to "gasify" the chloroform so it could be passed through a plastic tube into some freezing cold water, where, because of it's low density it would sink to the bottom and be easily identifiable. This synth worked with around 4ml yields of CF from 100g Ca(OCl)2 and 40ml acetone. i was quite pleased and the effects are noticeable on inhalation for quite a while..i recall a "buzzing" sensation where everything was ringing....

but now i have read some stuff on here about chlorobutanol requiring CF, and i'm wondering if my CF will be pure enough, as i was just extracting with a syringe. would it be?
also, the chlorobutanol synth seems to be highly in question. did anyone ever work out an effective, and relatively simple synthesis?

[Edited on 21-5-2004 by nitroboy]

[Edited on 21-5-2004 by nitroboy]

froot - 21-5-2004 at 08:21

Just last night I tried chloroform synth using a more agressive distillation approach. Similar to your method but I used a still.
I placed the NaOCl in the boiling flask, above which I had the acetone in a seperation funnel with a stopcock. The condensor was obviously attached above the flask sidewards down to the receiver.
I used a magnetic stirrer to keep the NaOCl in the flask agitated so that there is no seperation between the 2.
Basically I dumped the acetone into the NaOCl and collected the goods. As soon as the gas evolution slowed down I removed the receiver. It took all of 20 seconds! Not sure about the purity but it certainly smells unmistakenly good enough

thunderfvck - 21-5-2004 at 12:44

Geez, I guess last night was the night of chloroform! I, too, did this experiment last night. I used 10.8% NaOCl, 800 ml's of this, with 21 ml's acetone. I got about 20 ml's of chloroform. I added it VERY I don't have tubing for my reflux condenser yet and I don't want my chloroform to boil off (it has happened before when I added the acetone too quickly).

You don't really have to worry about total purity of the chloroform for the chlorobutanol. I always used it straight out as it was. But if you're concerned you could wash it with water a few times, then maybe some dilute HCl (NaOH is formed during the RX), then maybe some more water. But I don't think it's necessary.

Read the thread on chlorobutanol for a synthesis of it. It really isn't too hard. I wouldn't bother boiling off the excess acetone. Just throw it all into cold water and agitate the crap out of it to break up the oil. Good luck.

The_Davster - 21-5-2004 at 14:21

I too have used unpurified chloroform for a chlorobutanol synthesis. If you follow what I said I did on the first page of the chlorobutanol thread you will get a pure white product.

BTW: 2 months of storage and my chlorobutanol is still pure white and a solid:cool:, but it has caked together because it was not completly dryed.

thunderfvck - 22-5-2004 at 01:49

BromicAcid posted this reaction in the garage trichloromethan thread:

CH3COCH3 + 3 NaOCl ---> CHCl3 + CH3COONa + 2 NaOH

On Rhodium's site I have found:

CH3COCH3 + 6 NaOCl ---> CHCl3 + CH3COONa + 2 NaOH + 3 NaCl

I want to know what's going on here. With 6 moles of NaOCl, there is an expected much lower yield. With the 3 moles a higher yield is attainable. I recieved about 20ml's of chloroform...Using the first equation, theoretically I should get about 24 ml's. So this seems okay. With the second I, theoretically, should have obtained about 15 ml's. So is the second equation wrong? BromicAcid mentioned that NaCl could be added for "flavor", but by adding this it reduces the yield and appears incorrect. So...?

[Edited on 22-5-2004 by thunderfvck]

Marvin - 22-5-2004 at 09:14

The second equation is simply wrong. Check the oxygens on both sides.

The mistake has probably been made because when chlorine is used half goes to NaCl, so the author based the equation on half of the chlorine from hypochlorite going to chloride. NaOCl doesnt do this being effectivly the half of the Cl2 molecule that disproportionated high, ie its in oxidation state +1, chlorine is oxidation state 0.

Cl2 + 2NaOH => NaOCl + NaCl + H2O

thunderfvck - 26-5-2004 at 15:29

Is a link to my proposed mechanism. I was wondering if this is correct?

It equates to:

NaOCl + H2O ---> HOCl + Na+ + OH-
CH3COCH3 + 3HOCl ---> CHCl3 + 3H2O

Damn. Now I realize that the reaction between water and NaOCl PRODUCES hydroxide...So there's no need of the carbonyl oxygen to grab the Cl..although I guess it would do this anyway? Since the Cl has a delta + charge? Hmmm. But if this isn't of importance, then the hydroxide would simply attack the adjacent carbon's hydrogen...and so the cycle would begin.

What happens in the last step? Since I have the Cl attached to the carbonyl oxygen, is it just dropped off? It's a fairly stable ion...Or does it reform the hypochlorite (not likely, I suppose)...?

And when I wash the chloroform with dH2O, the water layer gets milky. Even after it's been washed many times with HCl...Is this due to the sodium acetate?


blazter - 29-5-2004 at 05:37

You'd want to wash using saturated salt solution. The milky color seen in the distilled water your using to wash with is probably the chloroform. In my limited experience I found that when the rxn mixture became cloudy, it took several hours for the chloroform to "precipitate" or to condense together into a single blob. You must also remember that chloroform is fairly soluable in water even though it is considered nonpolar, about 1g per 200g H2O IIRC. Using a saturated salt solution to wash with makes the water more polar so to speak, and it can dissolve less chloroform in each wash. About the only reason I can think of to wash the chloroform would be to remove some of the water in it, and any unreacted acetone.

EDIT: I'm suprised that nobody has mentioned that huffing chloroform is generally a bad idea, in response to the thread starter. If you must huff something you should only use N2O or nitrous oxide. It's been used for a couple of centuries in dentistry with very minimal side effects. The same can't be said for chloroform or ethyl ether as they can have some very bad side effects, just find a MSDS on chloroform and you'll see what I mean.

[Edited on 29-5-2004 by blazter]

Polverone - 29-5-2004 at 09:02

I don't think diethyl ether is bad as an anaesthetic. Unlike chloroform and trichloroethylene, it's not toxic to organs. It is very flammable though.

S.C. Wack - 29-5-2004 at 11:14

Et2O= massive hangover. People used to drink it btw. On topic, I've fooled around in the past with cold chloroform making. Heat isn't really required for formation.

Did this with cold hypo, and acetone in the addition funnel. Shaked occasionally, never enough to give much gas. Eventually, chloroform precipitated, but not in high yield. Some excess of acetone was used. I think 50 ml would be more than enough for a gallon of 5.25% NaOCl solution, if I remember right.

Noticed that pressure inside the vessel helped precipitate the CHCl3- otherwise the solution is just cloudy. Also learned that CHCl3 and 2L plastic soda bottles are not compatible.

Well, thats all pretty worthless really, and not recommended. I do recommend a cold solution of bleaching powder and slow addition of acetone though. I also recommend the lower grade of hth instead of the super grade. Go figure.

This is probably mentioned somewhere else, but chloroform from acetone is purified by shaking with conc. H2SO4.

[Edited on 29-5-2004 by S.C. Wack]

Magpie - 28-1-2006 at 12:04

I tried making chloroform using the haloform reaction. I used the HTH pool Ca(OCl)2 "Super Sock It" which is supposed to have at least 75% available chlorine. My procedure said to add the acetone in 2mL increments and cool the flask with cold water if the reaction becomes too vigorous. I had about 2/3's of the acetone added and the flask wasn't very warm so didn't think I would have to cool the flask. All of a sudden this reaction took off and it was "Whoa Nellie!" The reactants filled the flask and ran out the top of the reflux condenser. See attched photo. Needless to say I will have to try this again. :o

[Edited on 28-1-2006 by Magpie]

[Edited on 28-1-2006 by Magpie]

haloform runaway.JPG - 201kB

Chris The Great - 28-1-2006 at 16:59

I had it foam over too. It gets thick from the Ca(OH)2 precipitating so it foams when it heats up and the chloroform starts boiling. At least, that is waht appeared to happen with me. Glad I was wearing gloves, that hot Ca(OH)2 would not have felt good on my hands as I ran outside with the jar.

Esplosivo - 29-1-2006 at 00:28

Same here. When I tried it I cooled the propanone and calcium hypochlorite soln, and after mixing some of the propanone to the hypochlorite nothing seemed to happen. Stupid me, I tried to warm it up slightly by placing it in a water bath of approx. 50 deg C. It foamed and was impossible to control.

Off topic really, since the following uses distillation but anyways I hope it's useful to some of you. I tried it again, using a distillation set up. I warmed the hypochlorite solution and via a dropping funnel I added approx 2mL of acetone to the warm hypochlorite drop by drop. The mixture warmed up but I was able to control it. The addition was continued and the chloroform that formed was immediately distilled over. Acetone, although having a lower boiling point, did not distill over because of the large excess of hypochlorite, with which it readily reacted. I would have preferred to use a magnetic stirrer because most of the hypochlorite (or calcium hydroxide ?!) settled at the bottom, but I didn't have one. This method worked fine, but it was only carried out as a curiosity since I had no use for it and only produced some mLs before stopping the process.

[Edited on 29-1-2006 by Esplosivo]

Magpie - 30-1-2006 at 22:01

I gave this synthesis another try yesterday. I added the acetone (18.5 mL) to the 150 mL H2O + 50g HTH pool shock 2mL at a time as before. However, this time I had the RBF resting in a large bowl of ice-water. After each addition I would remove the ice-water after a bit and move the whole setup to swirl mix the reactants. I think a magnetic stir bar could have been put to good use here (my procedure predates their availablity in school labs). At the end I removed the ice-water and swirled occaisionally for a full 10 minutes. The flask was just warm to the touch.

According to procedure I then recovered the chloroform by steam distillation. Based on chloroform's vapor pressure I expected about 20 mL of codistillate to come over at a little less than 57C. That was pretty close in volume and T = 52-54C. I then washed with 10mL H20, separated, and dryed with CaCl2 per procedure. Net chloroform was about 17 mL.

Here's a photo of my steam distillation set-up. It worked OK once I insulated the steam trap and the upper part of the generating bottle. The 2 foot (60 cm) tube in the generator is a safety relief device (it works too ;) ).

I realize now that I have been posting on the wrong thread. "Garage experiments with trichloromethane" would have been better. If a moderator wants to move this that would be good.

steam distillation of chloroform.JPG - 186kB

jon - 31-1-2006 at 19:47

I tried adding salt to the reaction I would do it in an ice chest with plastic bags packed with ice to cool it after reaction I would use salt to crash out the chloroform for seperation.

Magpie - 31-1-2006 at 20:03

My RBF size is limited to 500 mL so just using an ice bath and slowing down on the acetone addition rate works well for me.

I tried using a 2" (5cm) magnetic stir bar today. It worked at first but eventually got bogged down and didn't mix. So back to the swirl method.