First of all, I use benzene 1 L to dissolve 500g of 2b4m, and it can’t dissolve completely at the beginning, so I heat it up a little until it dissolves, after that, the solution is warm but not boiling. I used 10L round bottom flask
2. I prepare the NaOH aq solution (300g of NaOH and 600ml water, just enough to dissolve it), I let it cool to room temperature, then I add it to the part 1 solution. Right after I add it at once, some deep brown oil coming up, then I start the stirring, the whole thing turns to brown and release some smoke ( just little), then I measure the temperature immediately, it is around 40-45 degrees. And I never stop the stirring.
3. I prepare 400g of MA.HCI, I added it in very small portions, around 10-20g each time, it took me around 2 hours to finish, because I keep the temperature around 45. And I can see the bottom has NaCI keeps piling up, and has some bubbles coming from bottom too. After I added all the MA.HCI, I keep stirring until it temperature drops itself.
4. I filter the NaCI out, and I wash it with water Twice, the whole solvent is still dark, then I proceed to acidification with 5:1 acetone and HCI until ph5, drop wise with needle. But still dark.
I afraid I was done something wrong, in fact, as long as I texting this reply, that dark solution is currently sit in my fridge for 3-4 hours already. I’m really seeking help about it, I pray I could have some result tomorrow, best regards.