Author Topic: So close!!! Only 3.1 grams & Xylene went yellow  (Read 1902 times)

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chemstu1320

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So close!!! Only 3.1 grams & Xylene went yellow
« on: June 02, 2004, 04:33:00 PM »
Swim is about to rip out the few remaining hairs left from this frustration.  Swim is so close to having dreams come true it's troublesome.

MM Benzo Wacker was performed.
   >Yield of ~110g (not bad for first wacker Swim thought!)

MM Al/Hg amination performed.
   >Ran hot and almost all aluminum was broken down. Definate grey/steel blue color indicating success.

Tryed MM recamended extractions & washes, along with Dr. Gonzo's on two different attemts, dryed with MgSO4 (30min) and every time Swim gasses (Muratic over Sulfuric, stirred, and through a 400mm CaCL2 packed column). After only a min or so the xylene turns yellow:-(  A very small yield was recovered each time. ~3g  And usually it is yellow and needs recrystalization.

Swim thinks that a A/B extraction is needed, and may need to be re-basified to get pH around 11-14 from reading other posts.  Swim has also caught wind the the first time you basify HALF the amount of NaOH should be used.

So I have 2 questions.

1.  If half the NaOH is to be used to basify, should half the water also be used?  Or just reduce the amount of NaOH?

2.  When it's time to re-basify to bring the pH in the 11-14 range, what would be a good quantity of DH2O & NaOH to use?

Any other ideas on what is going on, or possible fixes would be a life saver, also ease up on the unnessacary use of sassafras!!! ;-)

Thanks.
Chemstu1320

ning

  • Guest
I'm not an expert
« Reply #1 on: June 02, 2004, 06:43:00 PM »
I don't think the amount of water should make too much difference, as long as the pH is right.

How is it SWIY can get liters of sassy oil and not some cheap pH paper?


chemstu1320

  • Guest
Still learning......
« Reply #2 on: June 02, 2004, 06:55:00 PM »
Still learning along the way.  Swim has found that even though mistakes have been made, it has tought a valuable lesson on what NOT to do next time.  Trying to stick to the MM writeup word for word, never knew the pH would become an issue along the way.  Never the less, pH strips are on the way! ;-)

cs1320


abacus

  • Guest
Grey blue reaction means your aluminium is...
« Reply #3 on: June 06, 2004, 04:34:00 AM »
Grey blue reaction means your aluminium is breaking down which may be due to nitro (if you are using that, because i see no reference to using methylamine.hcl in the post).

This does not mean you are getting a successful animation of the ketone.

A/B wash is essential, as well as vacuum distilling the freebase AND recrystallising.  Do this instead of the MM workup if you want a decent final product, but thats not going to solve the lowish yield problems at present.