potisgood (Newbee)
02-28-02 13:44
No 274924
      Two ketone fractions?  Bookmark   

The distillate I collect from my EtONO wacker is really fucked up.  Instead of one peak corresponding to ketone, I got two.  One was around 120C and the other around 150C.  Neither was safrole.  My vacuum was constant the whole time as well.  I even took drip rate vs. temperature data and plotted a graph.  The graph showed that there were two peaks in the collection as well.  My theory is that both of these peaks are relatively pure ketone, but one of them (probably the higher one) is an azeotrope that the ketone forms with either its polymer or some unhydrolyzed acetal.  I suspect this, because I have found that the acetal forms a minimum azeotrope with safrole, even in very small quantities.  The lower fraction was pale flourescent green (like lemon-lime powerade) and the higher fraction was more like piss yellow.  Both fractions were about equal in size.  I have yet to aminate it, as I am trying out a new procedure for then amination and need to perfect it first.  I would post the graph I made, but I don't know how.  A while ago, I read about someone getting a strange liquid when distilling ketone from a performic rxn, but I can't find the post.  Does anyone have any clue whats going on?
(cheese head)
02-28-02 14:03
No 274935
      Re: Two ketone fractions?  Bookmark   

Sounds like the second run over is the ketone, judgeing by the colour(piss yellow). BUT MDP-2-P can vary in color, yes.Plus the greenish color is noted alot with MDP-2-P, how cool and strange at the same time. If your vacuum wasn't consistent, maybe it's all ketone. You should try combining a small portion of both fractions and see what the color change is like.Sonds like the combination of the 2 colors would bee right on the money, wierd eh!?Sounds like you know what you're doing anyways. GOOD GOOD. One day cheese will see that ketone drip into collecting flask too and all will bee well.

         May The Source Bee With You...Always.
(Hive Addict)
02-28-02 20:42
No 275136
      Re: Two ketone fractions?  Bookmark   

TLC? NMR? Nope? Well...

Keep each separate and try and form the oxime with each... make sure to get a MP for both oximes if they both form oximes. If this is carefully done you should get a decent answer to your question.
(Hive Bee)
02-28-02 22:15
No 275165
      Re: Two ketone fractions?  Bookmark   

Swim has seen ketone that had a green tint in the recieving flask that dissapeared apoun cooling for a couple of hrs in the freezer leavin it piss yellow.
(Pioneer Researcher)
03-01-02 17:51
No 275540
      Re: Two ketone fractions?  Bookmark   

If not TLC, bisulphite is a good choice too
(cheese head)
03-02-02 00:17
No 275668
      Re: Two ketone fractions?  Bookmark   

Why don't you just combine the two portions and re-distill? Then you might get one big fraction the right color!!smile

Cheeseboy-a whiteboy with Soul Like a black guy without soul
May The Source Bee With You Always.