Carrying out a vacuum distillation
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- čas přidán 6. 06. 2016
- Watch how to carrying out a vacuum distillation.
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I love the use of an air bleed with capillary tube:stops bumping better than magnet stir. You should use a Claisen adapter between boiling flask and thermometer adapter to stop bumping liquid splashing into the condenser.You can heat the Claisen adapter by wrapping it with insulated Nichrome wire and use small variac to adjust the heat to the wire.That wire can be extended to a possible fractionation column also.Finally,you should wrap the Claisen and possible fraction colum first with ceramic angel hair and aluminum foil.
I''ve studied some basic chemistry at university level. Mostly out of curiosity. I've done a few simple/safe experiments in a simple lab I've set up in what was once a garage. (It has proper ventilation, proper work benches, emergency showers, manual AND self-triggering fire suppression. I'm kind of proud of it, but it was fun to make.)
To the question: I'm interested in making a simple vacuum distillation, but I don't have access to liquid nitrogen for the cold finger trap. I live in northern Sweden, so I could buy CO2 ice, but it'd be gas by the time I got it home and set everything up. Do you have any ideas how to solve this?
Question 2: A proper lab pump costs £3.000-£10.000. Even if I had that kind of cash I'd spend it on something else. I've tried the £10 pumps from Chinese retailers. They look like an electric engine with a plastic piston mounted on the end. They don't work. At all. Period.
I'm not looking for a diffusion pump with perfect vacuum, just enough vacuum to remove organic solvents from heat sensitive chemicals. Do you have any idea what pump I should look at?
Sincerely yours
R Johnson Not sure how I got here, but perhaps I can help. Look for a diaphragm pump (means it doesn't work off oil), and try to find one that's PTFE lined, which is capable of handling any stray vapor that passes through it. You can find reasonable prices through eBay or similar. They're not cheap, but a good vacuum pump is one of the best investments you can make for a home lab. Just be safe with vacuum distillations and take proper precautions, they're a different sort of beast from standard distillations.
You might be able to get by with an old refrigerator or air conditioning compressor.
A simple vacuum pump can be made by using a water-jet pump [dont flush it through the sink!], I used it in the past a lot. The only thing you need is a continuous flow of water[bucket and aquarium pump] and a cheap water-jet pump [which simply can be made by spare parts]
R Johnson Dry Ice in a cheap styrofoam cooler can last a long time, maybe several days? Since posting, I've used a cheap Harbor Freight ($100 USD, branded Chinese import) intended for air conditioning repair work. It doesn't pull a strong vacuum (or I still have leaks), but it does allow distillation at much lower temperatures than normal. Good luck!
Rotary vane pump. 200 quid will get her sucked down to the microns of mmHG, which will boil the F*** out of water at negative fahrenheits/celsius degrees.