Sciencemadness Discussion Board

Glas-Col Questions

smaerd - 1-3-2010 at 14:55

So I am sorry for being completely ignorant about the subject. I have browsed around but with little to no luck. Perhaps I don't know the right terminology to do a proper search.

How does one control the electricity going to a glas-col? A rheostat? where could I find a suitable one? Do these controllers vary dependent on the wattage of the glas-col?

Or would it be more reasonable for a novice chemist to use a hot-plate with heated water bath for distillation of essential fragrances?

Thank you for your time:D!

[Edited on 1-3-2010 by smaerd]

entropy51 - 1-3-2010 at 15:14

I prefer a variac but

minitrols are also quite good.

You can even use a light dimmer if the current (amps) drawn by the mantle is within the rating of the dimmer.

Heating on a hotplate would work, but a hot water bath will not work if you're trying to steam distill.

smaerd - 1-3-2010 at 15:50

Would it be stressful working with 250ml flasks for most distillation purposes? or would this not be much of a limitation?

Magpie - 1-3-2010 at 15:56

Yes, I've used PowRtrols (Fisher, VWR) at school and found them quite nice, but very expensive. I was lucky and picked up a beat-up old variac type on eBay for not much. It's rated for 360w maximum but this is fine as my largest Glas-Col (500 ml) is only 270w. See picture below.

You can use a water (or oil) bath on a hotplate and I use this approach when I have a heat sensitive compound and want to definitely control the maximum temperature. For that I use a hotplate with a PID control loop. The control loop is not essential but beats manual control.

power controller.jpg - 45kB

[Edited on 1-3-2010 by Magpie]

hissingnoise - 1-3-2010 at 15:58

If you're fairly new to distillation, 250ml or better, 500ml would be a good start-off point.
And you'd soon find it more relaxing than stressful. . .

smaerd - 1-3-2010 at 16:01

Thanks for all the great advice here guys, it really means a lot. It's challenging enough getting into this sort of thing, so I really do appreciate it.

entropy51 - 1-3-2010 at 16:12

Get one of the introductory technique manuals such as Kubrick's Organic Chem Lab Survival Manual. Hint: Check out the 4shared link under S. C. Wack's signature on any of his posts. Thank you S.C.

Sandmeyer - 1-3-2010 at 16:23

You can call around to university labs and ask to buy an old dusty roto-evaporator, but they are mostly giving the old stuff away since it is going to end up on the junk yard otherwise and it is taking up useful space by collecting dust. Of course, not all groups do this, and it depends of your country, but if you ask many your chances increase. :) A friend was recently offered to take a complete 300 MHz NMR for free if he can just dismantle it and transport it himself.

The average person will go to any length to avoid thinking. -- Thomas Edison

Indeed, thinking was something Tesla did...

smaerd - 1-3-2010 at 17:59

Welp I just ordered a used 250ml glas-col + controller + stand adapter for 50 bucks including shipping! Seems like a steal considering the prices I saw for these things new.

Thanks for the help this will be fun to play with :)