Sciencemadness Discussion Board

Ethanol oxidation with Chlorine gas ----> Acetaldehyde?

FedeJuninArg - 5-2-2015 at 12:21

Hi this is my first post and I've some doubts about this reaction:


CH3-CH2-OH + Cl2 -----> (CH3-CH)O + 2 HCl

I read many topics about this, but they all were about ethanol and hypoclorite.

I was thinking about dropping 6M HCl into TCCA, and bubbling Cl2 into anhydrous ethanol at 25ºC.If any acetaldehyde is produced, it'll boiled off and collected in another flask at 0ºC. The excess HCl could be collected in a 4th flask with NaHCO3 solution.

Could this be possible? Thanks

[Edited on 5-2-2015 by FedeJuninArg]

Oscilllator - 5-2-2015 at 14:53

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

blogfast25 - 5-2-2015 at 15:08

Quote: Originally posted by FedeJuninArg  
Hi this is my first post and I've some doubts about this reaction:


CH3-CH2-OH + Cl2 -----> (CH3-CH)O + 2 HCl

I read many topics about this, but they all were about ethanol and hypoclorite.



I'm no expert on the oxidation of primary alcohols but I doubt chlorine would work, bar in some very specific conditions.

Your best bet remains more tried and tested oxidising agents.

[Edited on 6-2-2015 by blogfast25]

mayko - 5-2-2015 at 15:22

Welcome! If it's acetaldehyde you're looking for, check out the thread stickied at the top of

Fundamentals > Organic Chemistry

Endo - 5-2-2015 at 16:06

I thought that the direct chlorination of ethanol was a preparation for chloral Hydrate.

Chloral Hydrate

blogfast25 - 5-2-2015 at 16:11

Quote: Originally posted by Endo  
I thought that the direct chlorination of ethanol was a preparation for chloral Hydrate.

Chloral Hydrate



That's what 'Oscillator's' link tells us, I think.

[Edited on 6-2-2015 by blogfast25]

FedeJuninArg - 5-2-2015 at 22:33

Quote: Originally posted by Marvin  
The other thread is,

http://www.sciencemadness.org/talk/viewthread.php?tid=2535

A mirror of the prep on Rhodium is,

http://designer-drugs.com/pte/12.162.180.114/dcd/chemistry/c...

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.



Here Marvin says that ethanol was saturated with chlorine at 60ºC... Chloral is made from acetaldehyde and chlorine, so, in some way, ethanol is first oxidized to acetaldehyde and then reacts again with more molecules of chlorine, to form chloral..
Maybe using less chlorine in 1:1 molar ratio.. :)