The synthesis was done as described on Rhodium's page, 140 g 5-bromovanilline was obtained in 96 % yield by bromination of Vanillin in 95% EtOH and than hydrolysed by refluxing solution of KOH with Cu powder. All went as described on Rh page, first white precipitate, than dark green solution. After 27 hours of reflux, the solution was cooled to approx. 60°C and neutralised to pH 1 by HCl.
During the acidification no precipitate formed, the solution turned dark yellow with a violet tint and after a while dark brown.
The solution was extracted 3 times with boiling toluene (total approx. 900 ml) ant the toluene cooled to O°C. But, only approx. 5 g of off-white-brown xtals (unreacted 5-BrV?) precipitated from the cold toluene and evaporation of the toluene (mother liquore) did not yield anything but 7 g of light brown xtals, mp=70-75°C.
The 3 litters of acidified water from the toluene extract have been kept for further experimenting.
Part of the solution was basified with KOH to pH=5,5 and a very fine precipitate formed (completely unfiltrable....). Another portion of Toluene was added, but it created an unbreakable emulsion..... after acidification to pH 1-2 the emulsion dissapeared, but nothing was extractet do the toluene layer.
Can someone please suggest what to do? Where is the 5-OHvanilline?