The Hive => Newbee Forum => Topic started by: ClearLight on January 13, 2004, 03:30:00 AM
Title: Akk! NaOH instead of Bicarb! on Mdp2p
Post by: ClearLight on January 13, 2004, 03:30:00 AM
I can't BELIEVE this.. I copied the data into the working notes w/ 5% NaoH rather than 5% sodium bicarbonate to neutralize the acid after the DH20 washes on a performic reaction. Everything was perfect until then. Immediately the aqueous layer went reddish brown and the bottom dcm looked like coffe w/ milk in it. I immediately dumped in some 15% H2SO4 to reverse the pH and now I have some OJ colored layer on top of the dcm and yellow/coffe underneath. After about 10 min the top oj layer is yellowish brown and the bottom dcm layer is still milky but more brownish green.
The NaoH was 4 gms in 150 mls DH20. H2S04 was 20 ml conc in 220 mls DH20
Have I screwed everything up, or can I still recover from this?? Please help asap! ( side reactions are looming!)
Title: don't sweat it
Post by: Antibody2 on January 13, 2004, 06:20:00 PM
nothing is fucked up, at all. An NaOH wash will simply extract different impurities than a mildler alkali, it will not hurt your ketone, just wash w/ H2O a couple times before you distill and you are good to go
Title: THX!
Post by: ClearLight on January 13, 2004, 07:01:00 PM
Thanks antibody... I ran a tlc plate ( posts coming when I get done) of the MeOH/H2SO4 completion stage product, one of the NaOH aqueous layer, and one of the DCM layer after I added the 15% H2SO4 to recover from the NaOH addition.
The plate showed exactly the same spot sequence before/after and nothing in the Water/alkali layer. Based on that info, I took a deep breath and appreciate your time posting a reply! Thx for the confirmation!
Title: NaOH as option
Post by: Rhodium on January 13, 2004, 07:20:00 PM
NaOH is actually an option, but with a bit lower yield: