for 1 liter n-formyl mix1,2-1,5 liter methanol, 700-850 gr KOH and 0,3-0,6 liter water. dissolve KOH complete. After it has cooled down a bit, put it in the fridge for a few hours. put this mix under stirring to the n-formyl and let mix half hour without heat. after go to 85-90C.
85-90 bacause boiling point from methanol is lower than water..
it will much more yield, i never would cook without methanol
and finally steam distillation is a must! (low temperature, more yield)
and you will get more yield , if you you use p2p formamid and little more formic acid.
if you have more formic acid you can cook at 140-145, this gives more yield.