Originally posted by Ozone
mmm. Indicating tar!
I don't think that mesitylene a sufficiently active ring to condense with acetone. It seems more likely that (all things being equal) the acetone
would self-condense far more readily (even so, the route catalysed by alkali works better, leading to reddish brown "crap").
My guess is that your chromophore is a larger conjugated condensation/dehydration product. The reversibility suggests that the chromophore is an
ionised form, though. Very interesting, usually (at least in my experience) the compounds which are more colored when acidic involve a charge transfer
complex with a metal, viz. catechol:Fe.
But--when strongly acidic, pH<0, phenolphthalein is *orange*, so we cannot rule out the cationic form leading to some (probably via reversible
dehydration) conjugated form.
A very interesting question--have you tried to isolate this stuff (TLC, etc.)? You will need to do this before you begin characterization.
Cheers,
O3 |