Sciencemadness Discussion Board

Ethanol chlorination..

greenyppols - 19-5-2005 at 10:03

Hi. Chlorination of ethanol aiming towards chloral hydrate.

I dont know if the pic will show up, but HCl dripped onto KMN04 to generate Cl2. Gas goes thru H20 and then thru H2S04 down into 95% ethanol.

The ethanol turned syrupy but did not solidify. Not enought Cl2? It ran about 2hrs total, after about 1 hr I turned on the heat under the ethanol and it refluxed for about a 1/2 hr, with me plugging and unplugging the power supply.

Green fog turned the water in the first gas cleaner piss yellow and when I was done I removed the hose and white fumes arose. Whats in this now?

H2S04 in the drying bottle turned it funky yellow too.

Any uses for these two substances? that Im not aware of yet?, otherwise I'll probably chuck 'em.

I suspect the ethanol needs way more chlorination. I've perused the threads, searched and planned...maybe not enough apparently.

Ideas? The syrupy ethanol is bottled up so as not to waste, for a 2nd try.

[Edited on 19-5-2005 by greenyppols]

Chloral Adventures 005.jpg - 92kB

another pic

greenyppols - 19-5-2005 at 10:06

Another Pic to give better idea.

Chloral Adventures 008.jpg - 54kB

Esplosivo - 19-5-2005 at 10:35

If it's chloral, add a sodium hydroxide solution to it and leave to settle. A bottom layer of chloroform shoudl be seen quickly enough.

Marvin - 19-5-2005 at 11:45

Not from personal experience, but the method I know of is rather sensitive to moisture. If dry chlorine is bubbled into absolute alcohol until it won't absorb anymore it is supposed to set solid forming chloral alcoholate, from which the hydrate can be prepaired. There is no refluxing involved as far as I can tell. I'm under the impression that the more water in the mixture the lower the yeild. Was the sulphuric acid doing a good job of drying the gas? Could you have used ethanol with less water in? If this isnt the problem then its certainly not enough chlorine. Are you sure refluxing the mixture doesnt decompose it at all?

assumed failure?

greenyppols - 19-5-2005 at 12:28

Marvin - No, Im not sure about refluxing, I tried NOT to (unplugging) but I read it was ok to just add distillate back, so I thought it'd be ok anyway.

ethanol was not absolute. dont know how dry chlorine was. Spectacular yield was not expected, low end, if anything.

the alcohol stayed clear, where the water and sulphuric turned pee yellow.

Esplosivo - Im not after chloroform.

I transfered the syrupy stuff to a flask and plugged a cork in it. Rinsed the bottle out with water.....white fumey stuff arose..would it be I only accomplished acidifying the hell out of the ethanol and am nowhere near chlorinating it for chloral?
I realize this is just a step, Id have to purify it after, but I cant get past this step.
Im wondering if Ithe first wash bottle didnt have enuff water to absorb hydrogen chloride this was to generate also?

greenyppols - 19-5-2005 at 13:17

great....seems generating CL2 this way makes the hydrogen chloride that makes HCl after I run it through the water...and the hydrogen chloride that wasnt being absorbed anymore by the water was apparently absorbed by the ethanol, after I found this

Ethanol, reacts with Hydrogen Chloride, to form Ethyl Chloride, (i.e. chloroethane) and Water.

I read this HCl water in the 1st wash bottle ends up around a concentration of 43% HCl, higher than the muriatic HCl of 31% or so? Inteeeresting....

So I must use more water next time? Or a cleaner source of CL2.

[Edited on 19-5-2005 by greenyppols]

[Edited on 19-5-2005 by greenyppols]

garage chemist - 19-5-2005 at 13:52

For one mol of alcohol, you need at least 4 mol of chlorine (assuming that all chlorine reacts- this is almost never the case, so more is usually required). Calculate it.

And absolute alcohol gives very low yields of chloral, a mixture of water and alcohol is usually employed. There was a thread about it here where the optimal mixture (which directly produces chloral hydrate) was posted.

The reaction of HCl with ethanol is of no importance here, as it requires special conditions (catalyst) which are not given here.

[Edited on 19-5-2005 by garage chemist]

Marvin - 20-5-2005 at 00:01

The other thread is,

A mirror of the prep on Rhodium is,

HCl I'm sure isnt going to cause issues with the reaction. The methods I have here (3 books) resemble closely the Smoothe method. Saturate anhydrous ethanol with chlorine, raise to 60C and stop when no more HCl is given off. Add conc sulphuric acid, decant, treat with calcium carbonate (or oxide, I forget, I suspect this step is to remove any trichloroacetic acid also), distill and add to water to form the hydrate.

I can't locate what I thought I'd read recently to indicate the more water the less chlorinating and the more oxidising happens. Several methods including Smoothe's specifically call for anhydrous ethanol, though Smoothe has added a lot of suspect hacks to a method presumably from a textbook.

Esplosivo's suggestion was to try making chloroform from a sample in order to test if what you had was fully chlorinated.

greenyppols - 20-5-2005 at 04:43

Marvin - Those were the posts I read and then couldnt find again, near the end where it adds HCl. (before I get hollered at, yeah I searched for it, I didnt go far into its depths)

I read the "sani-flush" version gives me ideas but those instructions leave something to be desired. lol. At least in what order to do stuff. I had hoped to reach the 1st impure status, as I have no 90%+ h2so4 yet for the next step in it. Im not sure if the impurities in the store-bought concentrated h2so4 plastic bagged black stuff will affect it and Im not inclined to find out. I'll get to that next when I have a reason too, like having impure stuff. Looks like vacuum distillation would be the best/easiest way to go as far as distilling the "blended" stuff out.

I also see I used WAYYYYYY to much ethanol..I used something like 225ml. Me bad. So I'll try again using 25ml of the stuff thats already stopped up.

garage chemist - so if one mole ethanol is 46g and one mole cl2 is 35g...
thats alot of cl2 if I can only expect 0.412 g of Cl2 from reacting 0.367 g of KMn04 with 6.2ml of HCl (I used something like 50g KMn04) ...Im surprised it managed to turn syrupy at all, but it must have been in the right direction, just way too much ethanol.
I didnt add HCl for water, becaue I thought I already had plenty of it. Thats what I get for thinking, I guess.
So Im thinking of taking 25ml of this and adding some HCl just to see if anything happens with what I've acquired. ha!Probably not..

garage chemist - 20-5-2005 at 07:06

Small correction: One mol of Cl2 is 71g (it's diatomic).
And with the 4 moles I meant 4 moles of diatomic chlorine.

I will also try the production of chloral hydrate at some time, because I now have an excellent chlorination apparatus which can chlorinate the hell out of every organic substance:D.
I managed to chlorinate toluene to benzyl chloride (temperature in the liquid 157°C) in about one hour (with a 500W floodlight 50cm before the reaction vessel).

A tip: make your chlorine from TCCA and HCl, it gives you two times as much chlorine from a given amount of HCl than with KMnO4.

Nice bubblers

chloric1 - 29-5-2005 at 08:39

Originally posted by greenyppols
Another Pic to give better idea.

Hey greeny, where did you get the pretty bubblers?

Organikum - 29-5-2005 at 09:54

You should be able to do this with TCCA in situ.

garage chemist - 4-6-2005 at 15:08

Now there's a verified synthesis procedure for chloral hydrate on
Thanks, Mephisto!

Note that if 45g of chlorine need to be absorbed, you have to bubble in 90g of chlorine because half of the Cl2 escapes as HCl. This is important when calculating the amounts of TCCA and HCl in the gas generator.

@ Organikum: That might be possible, but separation of the chloral would be difficult.

greenyppols - 27-10-2005 at 10:44

chloric- sorry for the obscene delay. Dont know how I missed the ?. I was going over the threads before I attempted this again.
The bubblers came from everyone's favorite on-line auction site.

gc - what is this apparatus which you describe? Got a pic, or description? And would a 400w MH HID light work? How about a 1000w HPS? I have both in air cooled hoods, so Im thinking the whole setup might sit right in the enclosed hood, if I stand the light on its side.

[Edited on 27-10-2005 by greenyppols]

AndersHoveland - 10-7-2013 at 16:58

Under some conditions, chlorine reacts with ethanol to form ethyl hypochlorite. For this reason, it may not be such a good idea to try to pass chlorine into methyl alcohol.
Ethyl hypochlorite can be formed by passing chlorine into a solution of water, ethyl alcohol, a limited quantity of sodium hydroxide. Methyl hypochlorite is a dangerously sensitive explosive.
Journal of the Chemical Society, Volume 50, p607

Ethyl hypochlorite reacts with sulfur dioxide to form ethyl chlorosulfonate, CH3-CH2-O-SO2Cl,

This could potentially be useful as a reactive alkylating agent, like dimethyl sulfate, though I am not sure if it is as hazardously toxic.

Here is a possible reaction mechanism for the chlorination of ethyl alcohol to chloral hydrate:

CH3CH2OH + Cl2 --> CH3CH2OCl + HCl

I suspect ethyl hypochlorite is not particularly stable, and could decompose on heating, in a similar way to the tautomerisation of acetone into its enol form.


CH3‒CH=O Cl[-] H[+]

H[+] CH2=CH‒O[-] HCl

(this tautomer of acetaldehyde would immediately become chlorinated by more chlorine, and indeed it is likewise known that acetone can be chlorinated in the same way to chloroactetone)


Cl‒CH2‒CHCl‒O[-] H[+]

Cl‒CH2‒CH=O Cl[-] H[+]

This chlorination process then repeats again two more times until the acetaldehyde is fully chlorinated on the β-carbon atom.

(at this point the chlorines are electron-withdrawing enough to make the aldehyde group acidic, and so it "hydrates" with water)


chemcam - 11-7-2013 at 09:42

I know what I am about to say doesn't really relate to the latest post but I was wondering what would happen if you ran chlorine gas through a condenser chilled in dry ice/acetone to get liquid chlorine and then added that to chilled ethanol would it help or hinder the chlorination?
Also, what if both the liquid chlorine and the ethanol were added together in some sort of reaction vessel that would hold the pressure of the expanding chlorine during warm up?

Are either of those methods worth experimenting with or is it an incredibly stupid idea?

bfesser - 11-7-2013 at 10:09

If your target is 2,2,2-trichloroethane-1,1-diol (<a href="" target="_blank">chloral hydrate</a> <img src="../scipics/_wiki.png" />;), I would think you would have issues; it has a melting point of 57 &deg;C, <em>well above</em> dry ice/acetone slush at -78 &deg;C. But perhaps a sufficient rate of reflux would wash any product (crystallized out of the refluxing solution) back into the reaction flask. <a href="" target="_blank">Chlorine</a> <img src="../scipics/_wiki.png" /> will condense at -34.04 &deg;C (1 <a href="" target="_blank">atm</a> <img src="../scipics/_wiki.png" />;), and I don't see a need to go far below that. Perhaps you could try cooling with a <a href="" target="_blank">mixture of ethylene glycol, ethanol, and dry ice</a> <img src="../scipics/_wiki.png" /> to achieve something around -40 &deg;C.

<img src="../scipics/_warn.png" /> Warning: I've had some bad experiences with CO<sub>2</sub>(s)/acetone&mdash;including a carbonated <a href="" target="_blank">Dewar</a> <img src="../scipics/_wiki.png" /> geyser in my old kitchen! That happened on one of the coldest days last (?) winter, needless to say, it was unpleasant having to ventilate the house for several hours. :o

[Edited on 7/13/13 by bfesser]