Sciencemadness Discussion Board

Synthesis of dichloromethane- question mark.

Mixe - 12-12-2021 at 09:21

So DCM is out. Illegal to use, sell and hold in all of EU. Certainly not an ingredient anymore in any OTC products in northern Europe. Every purchase illegal for a private individual without unobtainable licences.

Of course you could take your chances and order it anyway from some wonderful black market salesperson, but once you've had your shady chemicals caught in customs more than twice you're on a watchlist. And nobody got time for that.

This calls for synthesis. I find one thread in this forum about it (maybe my Search Fu is weak though, I'll gladly be slapped on the hands), with loosely held theoretical discussion about routes. All seem hard to accomplish for a happy home chemist, but not impossible.
Here is the thread

So the reason for a new thread: the old one was focused on just the theory of the synthesis, I'd like to discuss the very real practicality of it. Is there anyone out there who've taken a stab at this and has some experience to share?



[Edited on 2021-12-12 by Mixe]

Bedlasky - 12-12-2021 at 09:37

You can buy DCM from Poland legaly. My friend orded it few months ago without issues.

Mixe - 12-12-2021 at 09:41

Quote: Originally posted by Bedlasky  
You can buy DCM from Poland legaly. My friend orded it few months ago without issues.


No you cannot. Yes, you can probably order it, but receiving it is illegal in my country. And as long as the substance has to pass a border, you're potentially in trouble. But this is NOT what the thread is about. It's about synthesis, not procurement.

[Edited on 2021-12-12 by Mixe]

Texium - 12-12-2021 at 10:13

Forget about it. There isn’t a practical way for the amateur to synthesize DCM cleanly and economically. Use chloroform instead. If you think making chloroform as a solvent is too expensive or too much work, then you have no business thinking about making DCM, because the DCM synthesis will be more time intensive, expensive, and far more dangerous.

[Edited on 12-12-2021 by Texium]

Mixe - 12-12-2021 at 10:54

Hmmm, ok. I hear you. No, I absolutely do not think making chloroform is too big of a hassle. I've made it many times and have a good stock of it. But DCM is not part of my collection for reasons stated above.
Still, would be interesting to hear about any practical experiences anyone might have of making it.

Fery - 12-12-2021 at 12:18

Quote: Originally posted by Bedlasky  
You can buy DCM from Poland legaly. My friend orded it few months ago without issues.

Yes it was this package:
https://sklep-chemland.pl/en/odczynniki-chemiczne/cz-d-a/dic...

Texium - 12-12-2021 at 12:21

Wow! That's some remarkably cheap DCM. Pity that it probably wouldn't be practical to ship outside of Europe.

karolus28 - 12-12-2021 at 12:43

Quote: Originally posted by Fery  
Quote: Originally posted by Bedlasky  
You can buy DCM from Poland legaly. My friend orded it few months ago without issues.

Yes it was this package:
https://sklep-chemland.pl/en/odczynniki-chemiczne/cz-d-a/dic...


but chemland only sells reagents if you have a company right?
hadron scientific sells dcm too:
on allegro.pl(it's like polish ebay) https://allegro.pl/oferta/chlorek-metylenu-dichlorometan-cz-...

and their website: http://hadronscientific.pl/en/?s=Methylene+chloride

Tsjerk - 12-12-2021 at 13:03

https://www.laboratoriumdiscounter.nl/nl/dichloormethaan-99....

Deoplosmiddelspecialist stil sells small quantities to customers with an intent of use.

Also, DCM can't be synthesized in any reasonable way.

[Edited on 12-12-2021 by Tsjerk]

macckone - 12-12-2021 at 13:33

There is another thread on making DCM from chloroform.
The overall yield from chloroform is good but you have to do it repeatedly to get those yields as conversion per run is in the 20% range.
The amount of work is much more than the cost of reagents.
Better off making isopropyl chloride which is easier and has a high single run yield.
The flammability of isopropyl chloride is higher but the work is a lot less.

Both methods can be done from zinc metal, hydrochloric acid and the substrate, chloroform and isopropyl chloride respectively.

The thread on chloroform to dcm:
http://www.sciencemadness.org/talk/viewthread.php?tid=78041&...

The thread on isopropyl chloride:
http://www.sciencemadness.org/talk/viewthread.php?tid=30180

Both threads have a good reference.

[Edited on 12-12-2021 by macckone]

Triflic Acid - 12-12-2021 at 15:12

Well, I have a particular idea for those who don't have access to chlorinated solvents, you could try getting a large glass reactor, filling it with natural gas, and add TCCA. Leave this out in the sun, and after a few days, there should be a sizable quantity of mixed chlorinated solvents, which should work for most purposes as a solvent. Something with a drain at the bottom and you should have an on-tap supply of chlorinated solvents.

S.C. Wack - 12-12-2021 at 15:47

The answer is in threads titled "making dichloromethane" and "Reduction of an alcoholic solution of chloroform by zink and hydrochloric acid to yield dcm ?" It's not likely that anyone has tried it because it's a bit pointless.

Mixe - 13-12-2021 at 10:38

Quote: Originally posted by macckone  
There is another thread on making DCM from chloroform.
The overall yield from chloroform is good but you have to do it repeatedly to get those yields as conversion per run is in the 20% range.

The thread on chloroform to dcm:
http://www.sciencemadness.org/talk/viewthread.php?tid=78041&...
[Edited on 12-12-2021 by macckone]


This was interesting and sounds doable. Only problem is separating the resulting mix of chloroform and dcm ... or did I misread something?

Mixe - 13-12-2021 at 10:52

Quote: Originally posted by karolus28  
Quote: Originally posted by Fery  
Quote: Originally posted by Bedlasky  
You can buy DCM from Poland legaly. My friend orded it few months ago without issues.

Yes it was this package:
https://sklep-chemland.pl/en/odczynniki-chemiczne/cz-d-a/dic...


but chemland only sells reagents if you have a company right?
hadron scientific sells dcm too:
on allegro.pl(it's like polish ebay) https://allegro.pl/oferta/chlorek-metylenu-dichlorometan-cz-...

and their website: http://hadronscientific.pl/en/?s=Methylene+chloride


Quote:

https://www.laboratoriumdiscounter.nl/nl/dichloormethaan-99....
Deoplosmiddelspecialist stil sells small quantities to customers with an intent of use.


Well there's something. If nothing else, this thread turned out to be a great "polish chemsources"-repository. I love it. Keep'em coming.

macckone - 16-12-2021 at 06:40

Mixe,

The boiling points of chloroform and dichloromethane are sufficiently different that it isn't hard to separate.
They do not form an azeotrope.
The production procedure outlined in the paper boils off the DCM as it is formed which helps drive the reaction.

the science company in denver has DCM for sale again at exorbitant rates due to new regulations.
It is the same price for 4 liters as 500ml.
Ground shipping only, US only.

Texium - 16-12-2021 at 07:43

Quote: Originally posted by Triflic Acid  
Well, I have a particular idea for those who don't have access to chlorinated solvents, you could try getting a large glass reactor, filling it with natural gas, and add TCCA. Leave this out in the sun, and after a few days, there should be a sizable quantity of mixed chlorinated solvents, which should work for most purposes as a solvent. Something with a drain at the bottom and you should have an on-tap supply of chlorinated solvents.
How about next time you have a “particular idea” you think twice before blurting it out? Because that particular idea is trash for so many reasons…

Triflic Acid - 16-12-2021 at 08:35

and what is so bad about it?

clearly_not_atara - 16-12-2021 at 08:36

This paper mentions that 2,2-dichloromalonic acid diethyl ester can be obtained by direct chlorination of diethyl malonate:

https://pubs.acs.org/doi/10.1021/ja01150a151

Rather than reduction with LAH, proceeding to hydrolysis and decarboxylation will give DCM. Diethyl malonate may be commercially available depending on your location.

This is only likely to be useful if you want DCM as a reagent; in those cases, I'd be curious to see whether you can obtain dibromomethane as well.
Quote: Originally posted by macckone  

Better off making isopropyl chloride which is easier and has a high single run yield.
The flammability of isopropyl chloride is higher but the work is a lot less.

It's a shame that we don't have more information on precisely how and when iPrCl can substitute for DCM. For example, I'm guessing you can dissolve amines in it without much risk of alkylation.

In some cases, you might prefer to simply make diethyl ether.

macckone - 20-12-2021 at 15:14

clearly_not_atara,

isopropyl chloride is more reactive than DCM, especially in the gas phase.
But is still a chlorocarbon, it will react with very strong acids (fuming sulfuric) and strong bases, but so will DCM.
It can react with water or alcohol to form isopropanol or ether correspondingly at high temperatures (which would require pressure).

Texium - 20-12-2021 at 15:35

Quote: Originally posted by Triflic Acid  
and what is so bad about it?
Let's see... filling a glass container with flammable gas and an oxidizing agent is already a not so great idea. Additionally, your "sizable quantity" of chlorinated solvents is not so sizable, because 1 mole of methane at atmospheric pressure will fill about 22.4 liters, while 1 mole of chloroform is only 78 mL. So even if you had a 23 liter container for this, your maximum yield if you somehow managed to react 100% of your natural gas, and assume that your natural gas is pure methane, and that it will be fully converted to chloroform, will yield a pitiful 78 mL, which would be much easier to make by the haloform process. You'd have to engineer some kind of flow process for it to approach practicality. Leaving a pile of TCCA out in the sun is also not a very efficient method for generating chlorine gas. In fact, I don't know if that works at all...

And that's not even touching on the fact that natural gas intentionally contains thiols, which would contaminate your product with sulfur containing nastiness.

And in the end, at best you would have a mixture of chloromethanes contaminated with smaller amounts of chloroethanes and chloropropanes with variable boiling points and reactivity, which is inferior to a pure solvent.

Go try it if you're still confident and want to prove me wrong. Otherwise, think twice before posting more poorly thought out, idealistic armchair chemistry.

SaccharinSlayer157 - 20-12-2021 at 22:46

Quote: Originally posted by Texium  
Quote: Originally posted by Triflic Acid  
Well, I have a particular idea for those who don't have access to chlorinated solvents, you could try getting a large glass reactor, filling it with natural gas, and add TCCA. Leave this out in the sun, and after a few days, there should be a sizable quantity of mixed chlorinated solvents, which should work for most purposes as a solvent. Something with a drain at the bottom and you should have an on-tap supply of chlorinated solvents.
How about next time you have a “particular idea” you think twice before blurting it out? Because that particular idea is trash for so many reasons…


Quote: Originally posted by Texium  
Quote: Originally posted by Triflic Acid  
and what is so bad about it?
Let's see... filling a glass container with flammable gas and an oxidizing agent is already a not so great idea. Additionally, your "sizable quantity" of chlorinated solvents is not so sizable, because 1 mole of methane at atmospheric pressure will fill about 22.4 liters, while 1 mole of chloroform is only 78 mL. So even if you had a 23 liter container for this, your maximum yield if you somehow managed to react 100% of your natural gas, and assume that your natural gas is pure methane, and that it will be fully converted to chloroform, will yield a pitiful 78 mL, which would be much easier to make by the haloform process. You'd have to engineer some kind of flow process for it to approach practicality. Leaving a pile of TCCA out in the sun is also not a very efficient method for generating chlorine gas. In fact, I don't know if that works at all...

And that's not even touching on the fact that natural gas intentionally contains thiols, which would contaminate your product with sulfur containing nastiness.

And in the end, at best you would have a mixture of chloromethanes contaminated with smaller amounts of chloroethanes and chloropropanes with variable boiling points and reactivity, which is inferior to a pure solvent.

Go try it if you're still confident and want to prove me wrong. Otherwise, think twice before posting more poorly thought out, idealistic armchair chemistry.


Wow, I had absolutely no idea Tex was such a massive jerk. I guess I'll stop expecting constructive criticism from admins and instead start being afraid to post my questions and ideas out of fear of being ridiculed. So much for "Amateur" and "Experimentalistic"

[Edited on 21-12-2021 by SaccharinSlayer157]

Fery - 21-12-2021 at 03:45

Hi SaccharinSlayer157 you are welcome to post interesting ideas and experiments. We then usually discuss here whether it is worth to try that idea / route or whether there is better / safer / higher yielding route in home labs.

Texium - 21-12-2021 at 19:02

Quote: Originally posted by SaccharinSlayer157  
Wow, I had absolutely no idea Tex was such a massive jerk. I guess I'll stop expecting constructive criticism from admins and instead start being afraid to post my questions and ideas out of fear of being ridiculed. So much for "Amateur" and "Experimentalistic"
I’ll admit, I was rather harsh, and could have worded those posts better. However, this is not the first time that TriflicAcid has posted speculative ideas that are not well thought out and easy to find flaws in with only cursory research, so it really frustrated me when I saw him doing it again.

If he had actually tried this idea and posted about his results, or made it clear that he had considered some of the pitfalls and wanted to brainstorm workarounds, that would be amateur experimentalism, and I would happily offer constructive ideas. Blurting out an idea that popped into your head 30 seconds ago without considering any of the potential problems with it is not amateur experimentalism. That is armchair chemistry. I think the thing that bothered me most about that particular post was that he made it sound so easy. He wasn’t asking if it might work, he basically said “Here’s an idea, three easy steps and you’ve got chlorinated solvents on tap!” No references, no calculations, no precedent whatsoever, just blind confidence. Most of AJKOER’s posts are just as confoundingly misguided, but at least he tries to back up his claims with references, even though they are often only tangentially related.

It is not my intent to scare anyone away from posting here. Obviously creative ideas are welcome, and there are vastly different experience levels here, so some ideas that seem creative and exciting to some may not be to others. What matters though is that it’s clear that you did some research before you posted it. If there’s multiple threads already about your idea that you clearly haven’t read, or the answer to your question can be quickly found by a Google search or two, you haven’t done your due diligence, and frankly deserve a bit of ridicule. It’s not our job to do all the research on an idea you just posted on a whim. Giving good answers and constructive criticism requires time and effort, so if that’s what you want, just make sure you’ve put time and effort into your own post.

SaccharinSlayer157 - 22-12-2021 at 22:48

I'LL admit, I was kind of harsh too. I didn't mean to start name calling and I'm sure Tex isn't actually a "Massive Jerk". I just got a bit emotional because I'm often times in the same situation as Triflic Acid, thinking I have a great idea without immediately noticing crucial flaws. I'm sure it gets very frustrating as a regular SM user with a lot of chemistry knowledge seeing beginners say stupid stuff sometimes. I just think its important to realize that the way much more knowledgeable users respond directly impacts how comfortable beginners are posting anything at all. It's really cool how this was all kept reasonably respectful and cordial though, I was half way expecting to get banned or something! :o Sorry that I was a bit hostile at first, I shouldn't have been. Now I'll stop derailing this thread and go mind my business somewhere else!

j_sum1 - 23-12-2021 at 03:28

This truly is a remarkable site. :)


On topic. If I was tasked with making DCM, I would have no idea where to start.
Actually, not quite true. I would start with reading. And orobably finish there too.
It is great to see some truly maverick ideas because every now and yhen there is an element of genius to them. Great also to see the dumb stuff get shot down in flames. Because this is no hobby to have a blind spot. And it is good to be confronted again and again with fundanental principles, basic procedural matters, and safety considerations.

teodor - 23-12-2021 at 12:37

Chemplayer has a video about the preparation of chloroform from trichloroacetic acid. So, I am wondering, could a similar method be used to make DCM from dichloroacetic acid. And yes, this is only a theoretical question. I also see no point to synthesise DCM yet.

macckone - 24-12-2021 at 14:00

Haloform reactions generally require the alpha carbon be fully chlorinated.
But if you can make chloroform, you can use it to make DCM.
Yes it is tedious but it is a documented method.

Triflic Acid - 25-12-2021 at 16:26

@Texium, I also should have been more clear. When I said on-tap, I was referring to an easy to set up a system that could produce chlorinate solvents slowly over time, not an in-flow system. Using TCCA+H2O as a slow-release chlorine generator, this would produce a slow-release chlorine system, not as rapid as HCl + TCCA. I also should have specified that my reactor would not be nearly big enough for this, but that the OP could try to get a larger vessel to produce more industrial quantities. While a flow based system might be more effective, something like this https://pubs.rsc.org/en/content/articlepdf/2017/re/c6re00186... is much harder for an amateur to set up. Overall, I don't blame you for getting annoyed at me, as, looking back, I've honestly posted a bunch of un-specific shit.

Neal - 26-12-2021 at 08:57

Yo some years ago I was asking chemistry professors what are some chemicals to remove oil from keyboards? I tried all the stuff from the stores they didn't work, until I heard from a biochemistry professor that the oil from our finger tips is likely a fatty acid, then an organic professor said try dichloromethane.

Now I wanna know to try to buy it. I think in higher concentrations, DCM is like a syrupy liquid, but at lower concentrations, more fluid like water? Does Home Depot still sell something with them in the U.S.?

karolus28 - 26-12-2021 at 09:35

Quote: Originally posted by Neel  
I think in higher concentrations, DCM is like a syrupy liquid


no, it's kinda like alcohol

Metallophile - 26-12-2021 at 10:35

DCM doesn't have a concentration. It's a pure solvent, and it boils at 40C. I got 1 liter on Amazon for about $60, but I'm sure there are better deals out there.

Neal - 26-12-2021 at 12:27

Quote: Originally posted by karolus28  
Quote: Originally posted by Neal  
I think in higher concentrations, DCM is like a syrupy liquid


no, it's kinda like alcohol

Ah you're right, I was looking at this video, the syrupy part is DCM mixed with something else. https://www.youtube.com/watch?v=QdgpehUX3wU

macckone - 30-12-2021 at 16:42

DCM is no longer available in 'consumer products' in the USA.
You can buy it from places like

https://www.sciencecompany.com/Dichloromethane-4L-Reagent-AC...