Sciencemadness Discussion Board


Xellos - 6-3-2012 at 06:33

I mixed 40 ml of acetone (p.a.) and 2 g of NaOH powder, hoping to get aldol condensation to diacetone alcohol, possibly also mesithyl oxide and even to isophorone. However, the rection mixture turned red-brown in 30 mins, and 3-4 hrs later, yellow precipitate started to form. Reaction has been done at room temperature (20 °C now), without any solvent. I wonder what it is...

ScienceSquirrel - 6-3-2012 at 06:38


Xellos - 6-3-2012 at 07:42

I see... damn, I hoped for it to be something nicer... more like at most 2 products... oh well

AirCowPeaCock - 6-3-2012 at 08:26

That's the nature of aldol condensations, I believe...

[Edited on 3-6-2012 by AirCowPeaCock]

Xellos - 6-3-2012 at 08:50

Hm... I did a few aldol reactions and didn't get any polymer or ugly mixture of many products in small yields (although these were more like benzaldehyde+acetone, with finite products, and while trying to minimize the self-aldol reactions). I did this one for curiosity - what and how fast will happen.
Getting multiple products is fine for me - as long as these are all products of aldol reactions to the same degree with normal yields (and if they can be separated, it's great). This is just a polymer - not a mixture of specific compounds, way too big molecules for me to like, etc.

bfesser - 8-3-2012 at 08:55

Quote: Originally posted by ScienceSquirrel  

This article is now available in the reference section, for those with access:

AndersHoveland - 8-3-2012 at 23:53

Yes, acetone will condense with itself in the presence of a strong base.
Something like HOC(CH3)2CH2COCH3 will be the initial condensation product, but there will be further condensation.

Remember the acetone has an enol tautomer. Yet acetone can also condense in another way, such as the reaction of chloroform with acetone to form chlorobutanol.

I made a detailed post about acetone reacting with base on one of these science forums but it is not appearing in a search now.

[Edited on 9-3-2012 by AndersHoveland]

Adas - 9-3-2012 at 09:15

This experiment yields the same compounds as acid + acetone. I have done this few days ago, and I got a dark red solution. I believe the terribly (pesticide?) smelling substance is phorone or isophorone (isophorone is used in some pesticides, I smelled it everytime when one of my relatives was spraying garden against insects IIRC).