Sciencemadness Discussion Board

Review my guesswork chemistry - Chlorinating ethanol -> Chloroform

Junk_Enginerd - 10-4-2021 at 04:47

I want an easier and more effective way of making chloroform than the standard ones discussed here, so I'm doing some experimenting.

I read a bit about Trichloroacetic Acid and that destructive distillation of it with NaOH yields chloroform. Interesting. So how to make TCAA then... Chlorination of acetic acid with UV and catalyst... Sounds a little complex. Then I thought, well, acetic acid is basically oxidized ethanol, yeah? Hmm...

One thing led to another and now I've got a bunch of ethanol90/methanol10 getting bubbled with chlorine.

My bubbling stone didn't like that, and soon dissolved. So I took what I had laying around and made a bubbler out of copper tube. That really didn't like the chlorine and quickly colored the solution lime green. I took it out and put the tube back without bubbler for the time being. I noted however that now it appeared I didn't need a bubbler anymore. Even the larger bubbles were almost completely gone by the time they reached the surface.

Question 1: Did I accidentally introduce a pretty damn efficient catalyst?

My goal is to take whatever unholy mix of chemicals the chlorination of the ethanol/methanol mix results in, add NaOH and distill.

Question 2: What will the chlorination of ethanol done in this manner mostly result in? I'm cooling it with a water bath, keeping it between 30°C-50°C roughly. I understand this heavily affects what the product is.

Question 3: When I take this product, add NaOH, heat it and distill it, am I likely to get chloroform? What else will likely distill over?

Thanks

zed - 10-4-2021 at 22:50

Ummm. I'll have to read more.

But, I would proceed carefully.

Explosions may occur while Chlorinating Ethanol.

Usually utilized to produce Chloral Hydrate.

http://www.sciencemadness.org/talk/viewthread.php?tid=3919

j_sum1 - 10-4-2021 at 23:44

My OC is not good enough to work out what unholy mixture you might have arrived at. It won't be TCCA though. You are missing some nitrogen.

In reverse order...
What would make you think that chlorination of ethanol would have the same outcome as chlorination of acetic acid?
Where did you read that chlorination of acetic acid produces TCCA?
Why can't you simply buy TCCA as a pool chemical? It is common enough.
What is wrong with the haloform reaction using bleach? It is one of the most accessible reactions possible, with a well known mechanism and a few ways to fine-tune it to maximise yield. (Although IMO, going bulk, avoiding fussing around and accepting 50% is more practical.)
How are you producing chlorine if not using TCCA? (Yes, I know there are many methods, but TCCA+HCl has so many advantages over other approaches.)

Junk_Enginerd - 11-4-2021 at 01:06
Quote: Originally posted by zed  
Ummm. I'll have to read more.

But, I would proceed carefully.

Explosions may occur while Chlorinating Ethanol.

Usually utilized to produce Chloral Hydrate.

http://www.sciencemadness.org/talk/viewthread.php?tid=3919


Oh haha. I found this nugget of information there: "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"

I suppose the ethanol/methanol mix I had was sorely inappropriate then. I noted a lot of sources saying anhydrous was good, and I thought maybe ethanol/methanol mix would be just that.

Maybe this explains the pops and literal flames that burst from the chlorine bubbles once or twice. Hm. Interesting. Good thing I only did it at test tube scale.
Quote: Originally posted by j_sum1  
My OC is not good enough to work out what unholy mixture you might have arrived at. It won't be TCCA though. You are missing some nitrogen.

In reverse order...
What would make you think that chlorination of ethanol would have the same outcome as chlorination of acetic acid?
Where did you read that chlorination of acetic acid produces TCCA?
Why can't you simply buy TCCA as a pool chemical? It is common enough.
What is wrong with the haloform reaction using bleach? It is one of the most accessible reactions possible, with a well known mechanism and a few ways to fine-tune it to maximise yield. (Although IMO, going bulk, avoiding fussing around and accepting 50% is more practical.)
How are you producing chlorine if not using TCCA? (Yes, I know there are many methods, but TCCA+HCl has so many advantages over other approaches.)


Ah no, not TCCA. TCAA, TriChloroAceticAcid. I have plenty TCCA, I used it to generate the chlorine in fact. If I didn't I'd have used MnO2 or maybe electrolysis.

It seems chlorination of things regularly produce a whole range of products at different stages of chlorination, so I thought if destructive distillation of TCAA produces chloroform, perhaps the other products react similarly. I don't need pure chloroform, just want to use it as a plastics solvent.

The bleach haloform reaction requires such stupid amounts of bleach. I think it's inelegant for lack of a better word. I don't have easy access to cheap large amounts of bleach. And anyway if I absolutely needed chloroform I'd just buy it, but I want to do some experimentation for the sake of learning.

Fyndium - 11-4-2021 at 01:38

This is the part I fear of chemistry. Some reactions with very otc stuff appear very innocuous, but can produce compounds that spontaneously detonate.

But, apart from experiment and study, if means is to produce chloroform, one would want to look for the Ca hypochlorite and acetone reaction. It appears to produce superior yields compared to bleach as there is little water involved to dissolve the chloroform. I haven't tested it out because I've got two large bottles of chloroform lying around, but might at some boring day just to perfect the synthesis.

j_sum1 - 11-4-2021 at 01:45

Ha. That makes more sense.
My error.

Junk_Enginerd - 11-4-2021 at 03:16

Quote: Originally posted by Fyndium  
This is the part I fear of chemistry. Some reactions with very otc stuff appear very innocuous, but can produce compounds that spontaneously detonate.

But, apart from experiment and study, if means is to produce chloroform, one would want to look for the Ca hypochlorite and acetone reaction. It appears to produce superior yields compared to bleach as there is little water involved to dissolve the chloroform. I haven't tested it out because I've got two large bottles of chloroform lying around, but might at some boring day just to perfect the synthesis.


Yeah... I always keep some semblance of safety in mind if I'm combining a potential oxidant with a potential fuel. Most importantly I do these experiments outside. They're free to burst into a giant fireball all they want with little consequence for me...

I've done the Ca hypochlorite process and it worked well, if a little messy with all the calcium gunk that forms. Unfortunately it's been really difficult to find ca hypochlorite lately. I'm hoping it's just due to pool care products being off season. In that case it should be easy to find really soon.

Does the water even matter if you distill it? There's no azeotrope or something? I was thinking instead of doing the reaction super slowly I'd just give the reaction some room and leat the heat it produces on its own drive the chloroform fumes up.

njl - 11-4-2021 at 03:35

Copper halides are known to catalyze halogenation reactions. Without testing the product it'll be hard to say what's happening though. It could be oxidizing to form acetate, or any number of chlorinated C2 derivatives. Mix a portion with water to see if there is phase separation.

Junk_Enginerd - 11-4-2021 at 04:10

Cool. Really satisfying to unknowingly stumble upon something so effective. Gives me 1800's chemist feels hehe.

I did note separation happening after adding KOH aq solution. An oily layer formed on top. I suppose it's hard to say anything about its density since I've no clue was the water density was with all the KOH and other stuff in there. It wasn't much though, I'd estimate 1-5% of the total volume.

zed - 11-4-2021 at 07:48

There are further references to explosions, even in the absence of Methanol.

https://patents.google.com/patent/US2443183A/en

Me? If I needed some Chloroform, I would probably trot down to the local Dollar Tree, and buy some cheapo bleach. A buck a gallon hereabouts. Seems easy enough.

But... Continue. It appears you are making Chloral Hydrate, and Hydrolysing it with Base. A round-about way to make Chloroform, but interesting.

Can't buy Chloral Hydrate retail. I don't know if it is even available on prescription anymore.

I wonder what else is being synthesized during this process? Anything unsuspected and useful?

Lots of Spas and Swimming pools in my area. Calcium Hypochlorite is commonplace.

Did notice that I was generating Sodium Hypochlorite during a simple electrolysis experiment.

I was trying to generate some hydrogen, so I added some salt to my water, so it would conduct electricity.

Actually, it seems like Sodium migrates to one electrode, where it reacts with the surrounding water to form NaOH, liberating H2, while Chlorine and OH, head for the other electrode.

Soon enough, your Electrodes are corroded, and you have a container reeking of bleach.

Local shortage of Calcium Hypochlorite?

https://en.wikipedia.org/wiki/Calcium_hypochlorite

[Edited on 11-4-2021 by zed]

[Edited on 11-4-2021 by zed]

Junk_Enginerd - 11-4-2021 at 08:47

The equivalent of a buck here will get me about 75 cl of bleach, so 5 ish times more expensive. But again, I'm doing this for learning rather than a pressing need for chloroform.

I don't think I'll be getting chloral hydrate. That synthesis is what lead me down this trail though. The synthesis of chloral seems like it's very temperature sensitive, and very slow. Gotta do the chlorination starting at 0°C and then over several hours increasing temperarure to reflux. Otherwise the alcohol gets oxidized to... acetaldehyde I think? I'm running the reaction hot. According to the wiki, acetaldehyde smells like green apples, and I think I can smell some of that at least.

The solution has gone from being typical chlorine green to a deep amber too.

I have also noted that now that the residue has stood for a while, there are some pretty crystals forming. Looks like blobs of mold at a glance, but they're white spiky needle crystal balls.

I think chloral can be used as a drug of some sort, so probably not easy to find.

Fyndium - 11-4-2021 at 15:18

Quote: Originally posted by Junk_Enginerd  
I've done the Ca hypochlorite process and it worked well, if a little messy with all the calcium gunk that forms. Unfortunately it's been really difficult to find ca hypochlorite lately. I'm hoping it's just due to pool care products being off season. In that case it should be easy to find really soon.

Does the water even matter if you distill it? There's no azeotrope or something? I was thinking instead of doing the reaction super slowly I'd just give the reaction some room and leat the heat it produces on its own drive the chloroform fumes up.


Hmm, they stock them usually in large supermarkets, you'll likely know this well. I just saw 1kg and 5kg packages of them some time ago, but it's possible that off season affects it. But, it can be readily ordered online and I got my 5kg bucket years ago, which still hangs strong.

When making from otc 5% bleach, major issue would be larg'ish volume of liquid. For each 50mL of product (expecting 100% yield, dunno what's reality) you need to heat 1L of liquid, that's 20 liters to get 1L of chloroform, most likely much more as someone cited that it yields only 50%. Hence, Ca hypochlorite acetone method seems far superior if you need actual useful quantities of chloroform. Last time I used it, I went through almost 2 liters, which of over 90% I was able to recover by distillation, but still, that would ask for, what, 20, 40, 80 liters of bleach? And it definitely ain't so cheap at least in here, it costs about 1€ per 750mL bottle, with less than 5%, so for 1L of chloroform equivalent it would call for 27 bottles minimum. Ca hypo goes for less than 10€ per kg for me.

To be honest, currently I would just order bottles of chloroform through my company instead of making it. I know several places which supply it.

zed - 11-4-2021 at 22:41

Last time I checked Chloroform prices around here, it was expensive. One liter? One hundred U.S. Dollars!

It might be cheaper somewhere. I'll recheck.

OK, I'm back!

I did find a supplier that offered it for about $50.00 per liter.

Might send it, might not.

https://www.govets.com/index.php/labchem-226-cxg-9lg05.html?...

[Edited on 12-4-2021 by zed]

[Edited on 12-4-2021 by zed]

Amos - 12-4-2021 at 05:13

There are a lot of things you can do to analyze this mixture. Hopefully you measured a volume or mass of starting alcohol before, and you can check the weight now. You can leave a portion out on a watch glass and see if it either evaporates, or absorbs water from the atmosphere, gaining mass. The latter would be characteristic of trichloroacetic acid. You can add a sample to water, check the pH, and titrate it to see how acidic it now is. Lots of data you can work backwards from.

I'm not sure how feasible the formation of chloroethane and chloromethane from the HCl byproduct of chlorination is, but you did have a potential lewis acidic catalyst present, so who knows. Those two compounds don't have the greatest health and safety records and if they were formed could be dissolved in the reaction mixture, waiting to boil out from agitation or heat. A lot of halogenated organics are nasty, so be careful.