Preparation of ethanal (acetaldehyde) + Fehling's Test

We show you how to prepare ethanal via catalytic dehydrogenation of ethanol. A Fehling's Test is conducted to prove the formation of ethanal. Enjoy!

[peterkebangeu]

Epic procedure thank you can you show the method of makin paraldeyhde ? 😘

[SuperheroArmorychannel]

Would this process still work if the distillation occurred through a copper tube heated by a propane torch?

[AllChemystery]

would it be possible to instead collect the acetaldehyde directly via condesation with a salted ice bath in a small RBF rather than obtaining a solution of unknown concentration? i would suppose the dichromate oxidation may be better for that but this looks like an easily upscaled continuous process.

[alish]

Can i use the same catalyst for methanal ?
Platinized asbestos is more expensive than gold

[ferrischemistry]

Our profiles are nearly the same.
Even to the art.

[jaredgarden]

This is very good but i have a few questions.
Did you use ventilation, because generating hydrogen in a room with a gas burner going is asking for trouble.
Also how are you going to prepare PURE acetaldehyde, Its great being able to make a small quantity of impure acetaldehyde dissolved in water but we can all do that, ideally isolating it as a pure product would be more desirable as this could be made into the paraldehyde for storage and also be used in reactions, the aqueous solution containing large amounts of ethanol however is rather useless.

You need to set up a condenser for collecting the acetaldehyde instead, given the low boiling point this may be a pain but a normal ice bath on the receiver and keeping the condenser water below 10*C should suffice albeit you may loose a little product. I wouldn't advise salt water for the condenser water unless your water pump can handle it.
As for separating the acetaldehyde from the ethanol, im not sure if you could get away with fractional distillation but you might as well give it a go, another idea would be to try a desiccant that removes ethanol such as calcium chloride however there is no grantee that calcium chloride is not soluble in acetaldehyde but the calcium chloride might at the very least hold onto the ethanol a little better during distillation.

Third option although not a great one, would be to simply try and polymerize the acetaldehyde ethanol mixture and hope that paraldehyde isn't soluble in the ethanol.
This can be achieved by carefully adding conc sulfuric acid to acetaldehyde on an ice bath, at low temps and after dillution with water the paraldehyde will drop out of solution as a solid which can be filtered off.
You could then distill the paraldehyde BP 124*C.
Do not heat the paraldehyde in contact with acid however as this is how it is depolymerized.

[digifomation]

could instead of using copper powder using copper wool and heating it with electricity ?

[hazem]

Why was water used to dissolve the product and not to distill the product

[tanveershah]

hi i saw this video last night might b after 4 years.
can u advise me how to make around 50 kg acetaldehyde per day? with few cheap catalysts. thanking you in anticipation.

[SodiumInteresting]

Fun but why not just reflux ethanol with chromic acid ?

[mihailma]

Thank you for this wonderful demonstration. I tried to repeat it at school lab. I used about 10 cm3 of ethanol as starting material and the catalyst in a few minutes from black, turned copper color (i used 4-5 grams of CuO), obviously since it converted to Cu. This is indeed a sign that the reaction worked (and CuO became Cu) but in your video the catalyst doesn't seem to "be consumed" so quickly. Do i have to use more catalyst for this amount of ethanol?

[johnblacksuperchemist]

know how hypochlorous acid (bleach + AcOH) will oxidize a primary alcohol to an aldehyde and a secondary alcohol into a ketone. Well my question is the hypochlorous oxidation reaction work with ethanol and methanol to make acetaldehyde and Sometimes reactions with these lower weight alcohols do NOT work and so that is why i ask

[bigrockets]

I love you guys video, but that damn voice synth sure messes with your enunciation on some words, and your pretty voice