Author Topic: reductive amination w/ 200mm condenser  (Read 597 times)

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alkadelic

  • Guest
reductive amination w/ 200mm condenser
« on: May 08, 2004, 11:15:00 AM »
swims got a 200mm condenser and want to do mm reductive amination. there only two post i found in tfse about this.saying 200mm is two small to handle the reaction, dont try it. and the other said, he knew a bee that used a 200mm condenser and reaction went fine in an 18min addition with 25g keeping condenser ice cold. how can i improvise this procedure or setup. for a successful amination with 200mm condenser? how bout a half scale?, not my first choice! please help! theres lil info bout this in tfse...

OcoteaCymbarum

  • Guest
I wouldnt do it if I was you
« Reply #1 on: May 08, 2004, 03:36:00 PM »
But again thats me. I have a 600 mm allihin condenser just for that as it really gets hot, boiling! I would be scared the boiling methanol would just flow out of the top of the condenser. It really refluxes hard, and if you put in too much nitro when trying to drip at the proper pace and you will have a volcano with methanol spitting out!
I dont think it can work, unless the addition is extremely slow, your flask in on ice to keep it as cool as posible.
But again, I wonder about the amount of foil you would need to use to keep the nitro addition slow.
If this is your first time, and you cant buy another condenser(either a longer one, or the same but staked on top of your first one) then I wouldnt try to transform 25 g of the ketone. It will get way too hot when you drip the nitro in.

Of course this represents my own opinion and experience, and  I have run many nitros before I decided I was much better off synthesizing MeAm as a salt first Still if I run a reduction with it, I use my 600 condenser
Hope this helps, let us know of the results

slackdaddy

  • Guest
SWIS uses a 200mm condenser stacked on top of...
« Reply #2 on: May 08, 2004, 07:18:00 PM »
SWIS uses a 200mm condenser stacked on top of a 200mm vigreux column. It's a little bit makeshift but it works.  Addition is fast - within 5 minutes.  There is a bucket of room-temp water nearby when the reaction starts going out of control and swim swirls to agitate when the aluminum starts to swell up and stops the stir bar.  -tried using a bucket of ice water, and the yield went down ROOM-TEMP.

Methyl Man writeup X2 scale - 6 liter FBF, 3 inch stirbar, add 100 ml MEOH halfway through, standard workup, A/B. 50g mdp2p in 48g MDMA.HCl out before recrystallization.  Don't be afraid of this reaction.  It's violence is what makes it so much fun to watch.

If you want a laid back reaction, go for oxime acidic Al/Hg MDA.  Very chill reaction in a beaker, high yeilds, dancy trippy X.

Who's your daddy?


alkadelic

  • Guest
i found the following cheap condensors in some
« Reply #3 on: May 09, 2004, 01:38:00 AM »
i found the following cheap condensors in some sites, they also have 300mm and 500mm:
400mm Condenser - with rubber connection $19.95
400mm Leibig Condenser, flit glass, with stoppers $17.00
400mm Leibig Condenser,Borosilicate,no stoppers $14.50
any suggestion on wich one would work best w/ mm reductive amination? is bigger better?

ApprenticeCook

  • Guest
You just need a long column, the rxn like its...
« Reply #4 on: May 09, 2004, 02:23:00 AM »
You just need a long column, the rxn like its been said can get a bit violent at times.... swims nearly had the volcano, came within 2cm of the top of the condenser, now swim uses an air condenser ontop of the liebig, and pays great attention to reaction temp v addition rate.

Buy another condenser and put it ontop or buy another really long one. Either way, same result.


FlaskGenie

  • Guest
Sorry if this is a little off topic but has...
« Reply #5 on: May 09, 2004, 07:00:00 PM »
Sorry if this is a little off topic but has any bee's had any exp. with adding nitro to meoh/AL very slowly letting reaction produce Methylamine first . Then adding their Mdp2p to the grey slop.  It seems to swim this would work in theroy kind of half MM, half wet amination.  Swim was thinking in this case it might help with short condenser if the addition of nitro was very slow and non dependent of Mdp2p addition.

OcoteaCymbarum

  • Guest
MeAm is higlhy volatile
« Reply #6 on: May 10, 2004, 03:14:00 AM »
The bp is -6 degrees. It could work but you will loose alll of your MeAm(or lots) because it will boil away. Thats why its better to have some ketone in there for it to react with me MEAM as it is formed. Unless you were to keep the solution super cooled, but again, reducing the nitro group is highly exothermic, so I would tend to think it could be hard to do.

Another idea is to run both reductions seperately.
Maybe drip in the nitro in one RB flask, collect the MeAM in another flask, this one supercooled, wheighing everything. Then dump in your ketone, bang the solution turns orange. Add this to some activated aluminium for the final reduction. I've never tried this procedure, but Im sure it would work, provided you find a way to cool down your MeAM gas in between the 2 flasks

abolt

  • Guest
Thick al
« Reply #7 on: May 10, 2004, 07:02:00 AM »
You can use your 200mm condenser, if you use thick Al (0.3 mm) & add the Nitromethane, dripwise, slowly, then bring the solution to reflux and drip in the Ketone.

This is absolutely the best procedure for a first time bee. The only benefit from using thinner aluminium is that the reaction will be over quicker, however your chances of failure or a runaway reaction are greatly increased.

This info has been flogged to death in TFSE.