Pomzazed - 8-4-2010 at 22:09
Here I got bunchs of >97% Naphthalene in the form of commercial mothballs, and 18M of sulfuric acid.
Any Sciencemadness member having experience regarding sulfonation of these selectively to give naphthalene-1-sulfonic acid?
I know sulfonation of arenes is reversible (with desulfonation) and in case of Naphthalene, kinetic control seems to be favored to my wanted product
(1-position) while the more thermodynamically stable (2-position) may be avoided by reacting at lower temp.
The sulfonic product would be easily separated by extracting with base leaving unreacted naphthalene behind and recrystallyzed as its salt.
However, my concern is the reaction condition:
Will reacting these in ice bath enough to perform a monosulfonation at 1- ? I try not to get the 2- or the disulfonylation (at any position) products.
Chromatograph would be out of question in case I'm producing like 10s gram scale at home.
UnintentionalChaos - 8-4-2010 at 22:54
There is a whole thread on this already.
http://www.sciencemadness.org/talk/viewthread.php?tid=11663
Pomzazed - 8-4-2010 at 23:14
Wah, thanks UnintentionalChaos. Don't know how I skipped this topic in the search result, my bad.
So reacting in these condition (50 C) give mostly 1- isomer. But how much in extent that a 1,5-disulfonate by-product being produced? Is that so low
that is negligible after crstalization?