chemrox - 11-5-2008 at 19:52
I have prepared a viscous base and to purify it distillation is indicated. The material should boil at 65-70*C/35mm. There are about 100 ml of the
stuff. I think this is a water-pump/short-path still procedure. I'm affraid using a west condenser would lead to too much hold-up.
TextThanks,
CRX
MagicJigPipe - 11-5-2008 at 20:35
Just use a short West if you don't have a short-path. Why are you worried about a little holdup anyway? What is this "viscous base"? Without
knowing what it is, it's hard to give advice on what you should do or what to use.
chemrox - 11-5-2008 at 20:57
I have a short path still. I was wondering given the parameters I stated, would the short path route seem indicated? It seemed so to me. I have
another question though- I have been using an ice-bath. My T range is <10*C. So I made a bath with CaCl2 on ice that starts out around -12 in the
bath, 3-6* in the reaction vessel. As the procedure progresses the ice melts and the solution gets less cool. Midway I re-freshed it last time
becaue the time before it took two hours to complete the addition. I don't want to get side-tracked so I'll limit the information to this: the
reaction is exothermic and must be kept under 10*. It has to be an ice bath of some kind, and not too cold or the reactants might freeze. Ideas on
making cheap and effective ice baths needed. [this all gets more fun next month when I react the product with dimethyl Zn!!]
MagicJigPipe - 11-5-2008 at 21:14
I'd say if your tap water is 5* or more below your target temp you could just pump tap water through it as fast as you can. If your liquid won't
freeze at 0* then you could let your ice sit out until it's 0* and then put it in the bath.
I've used those gel packs for cooling lunchboxes before. Just leave them out until they get just a little below the freezing point of the mixture and
drop them in. I bought a whole bunch so I could keep recycling them. You know, take some out, put some in and by the time the ones in the bath are
too warm the ones in the freezer or refridgerator will be cold again. I like the "synthetic ice cubes". They're just little plastic things with gel
on the inside shaped like ice cubes. The cool thing with those is they don't melt and fill your bath with water that must be removed.