11-10-03 18:07
No 470059
I would like if possible to understand better the reasons for the several steps used after the Wacker oxidation. I would expose what I have been thinking about it, please correct me if and wherever I am wrong.
Filtering removes the PdCl2 catalyst.
Pouring the reaction contents in the 10 % HCl dilutes the DMF and creates a two phase solution, water + DMF on top, ketone on the bottom. Next we extract the watery layer with DCM and combine.
One question, why the HCl ? If using only H2O, same effect ?
Now, what about hydroquinone and p-benzo ? I think we have some of each mixed in with ketone, DCM and black tar.
Looks like both p-benzo and hydroquinone do not react with acids, it this correct ? I know hydroquinone is supposed to be removed with the NaOH washes. Same for any remaining p-benzo ? Does p-benzo reacts with NaOH as well ? What are the end products of the p-benzo + NaOH, hydroquinone + NaOH reactions ?
One last question, I have seen several times this asked, never answered : What is the reason for the sodium bicarbonate and brine washes ?
(Hive Bee)
11-10-03 22:45
No 470122
"Filtering removes the PdCl2 catalyst."
I wish you good luck trying that! Unless you do the filetering after the addition of NaOH.
(Chief Bee)
11-11-03 01:05
No 470142
One question, why the HCl ? If using only H2O, same effect ?
Decomposing intermediates into the desired end product. Follow the instructions.
What is the reason for the sodium bicarbonate and brine washes
Removing undesired contaminants (DMF, Salts) and pre-drying the solution. Post 394075 (pHarmacist: "Washing with brine", Newbee Forum)