If acetaldehyde is made to condense with itself under the influence of a base the product is, initially at least, aldol or 3-hydroxybutryaldehyde: The
Aldol condensation. The are many variations of this reaction included mixed aldehyde condensations.
I have been looking for examples where formaldehyde is used as one of the components and to my surprise and can find very little information on it. Is
this because it is not a true aldol reaction or that you just get a polymerised gunk most of the time? Is the formation of penterythritol from
formaldehyde and acetaldehyde an example of an aldol reaction and could you carry out this with a 1:1 ratio instead of 3:1 to get 3-hydroxypropanal or
with formaldehyde and acetone to get 1-hydroxy-3-butanone?
It seems such a simple idea that there must have been experiments into this system in the past but articles on the aldol reaction never cover the
formaldehyde examples. I did find one reference on a patent (DE 222551) to the formation of 1-hydroxy-3-butanone from acetone and formaldehyde but
only in passing as a starting material for the subject of the patent so there are no details of conditions. Can anyone shed some light onto this type
of reaction. At home I have a monograph on the chemistry of formaldehyde and I am sure this would be covered but unfortunately I am currently away
from home and not likely to b back for some time.Crowfjord - 25-9-2017 at 16:32
A paper regarding the subject was posted by plastics a while back, here. Nitroalkanes will add to formaldehyde as well, I can post the reference a little later when I get home.UC235 - 25-9-2017 at 17:20
A paper regarding the subject was posted by plastics a while back, here. Nitroalkanes will add to formaldehyde as well, I can post the reference a little later when I get home.
Indeed, the ubiquitous buffer "Tris" used in biology and biochemistry is produced in an analogous reaction to that forming pentaerythritol using
nitromethane and formaldehyde, followed by hydrogenation.Crowfjord - 25-9-2017 at 19:05
The reference I was thinking of relating to a nitro aldol with formaldehyde turned out to be a reference to this OrgSyn article for 2-nitroethanol.Boffis - 25-9-2017 at 21:43
Hi Guys thanks for the replies, last night I found a digital copy of the ACS Monograph on Formaldehyde on line (in fact in the SM library) and there
is a whole section on these aldol type condensations starting on page 150. I will read and digest!
