Finally some new results using quinhydrone (QH):
Expt 1As detailed in above post, using wet impure QH, etc.
Result
__> crap
Expt 2Similarly to 1, same wet impure QH etc., but then a whole lot of nasty personal stuff happened blah, blah
Result
__> inconclusive but probably crap
Expt 310g HQ + 2g QH(recrystallized from MeOH/H2O and dried in dessicator with H2SO4, crystals actually dark red brown but reflect green) + 12ml 95% H2SO4, all in 45ml MeOH.
Refluxed 5 hrs. Mixture was transparent dark reddish brown from the begining. Added 45 ml H2O. Distilled off most of the MeOH. Extracted with xylene (1x30ml,1x20ml). Evaporated xylene in vacuum.
Result
__> ~9.9g of chocolate looking solid. Melts with some warming. The mp of p-meo-phenol is ~52°C so this is an encouraging sign.
Recrystallization trials: Tried DCM, acetone & 'lacquer thinners' (which I suspect to be MEK cos it ain't toluene)
None satisfactory. Acetone looked best but it leaves a crystalline sludge (rather than a slurry) not easily filterable. Maybe acetone/H2O will work (add water to chocolate (wait isn't that a movie?), add warm acetone until all dissolved, evap acetone under weak vacuum so that bp < 52°C) ?
Anyhow, these trials eventually destroyed the product.
Expt 434.4g HQ + 6.9g QH(dry, recrystallized from MeOH/H2O) + 22ml 98% H2SO4, all in 145ml MeOH.
Refluxed 5 hrs. Mixture was transparent dark reddish brown from the begining as before. Realized didn't have enough extraction solvent, so had to distill some DCM from paint stripper. Mixture was stirred at about 30 °C in the meantime (~ 2.5 hrs).
Added 100 ml H2O. Distilled off ~ 100ml MeOH.
(After ~75ml distilled, a black oil started separating)
About 40ml of floating black oil afterwards.
Left overnight which was quite cold (maybe 5°C). Mext morning there was a white crystalline ppte in water phase, probably unreacted HQ. Extracted with DCM (1x80ml,1x60ml,1x20ml). Ppte dissappears. Evaporated DCM, leaving ~ 35 ml black (v. dark brown) oil. Solidifies on cooling.
Result
__> ~34g of chocolate looking solid. Melts when warmed.
Notes:
- Either the use of decent QH or refluxing seemed to make a significant improvement.
- Added less H2O in 4 than 3 hence the appearance of oil when distilling MeOH off.
- Would extract with less DCM next time (eg. 1x80ml,1x50ml)
- Couldn't measure mass of crude product (scale limited). Estimate of 34g based on vol of oil before solidification. Therefore not sure about yield & purity.
-Not going to bother with recrystallization again. Will use crude product in next reaction (R-T formylation to aldehyde using new patent found by Antoncho,
Post 330714
(Antoncho: "A patented improvement", Chemistry Discourse))