LD5050
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concentrating under vacuum
I have a mixture of isopropyl alcohol, water, and oil i want to collect the oil but don't want to get the mixture too hot by means of distilling at
atmospheric pressure. I don't have a cold trap or dry ice or anything so i know I wont be able to condense the alcohol vapors so should i just hook my
vacuum right to the flask and suck them through the vacuum will this work?
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CharlieA
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Why can't you just allow the isopropanol and water to evaporate at room temperature?
Do you know the boiling point of the oil at atmospheric pressure?
What is the oil?
Do you know how sensitive the oil if to temperature?
Sorry I have so many questions! 
But maybe I can come up with some suggestions later.
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JJay
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I usually try to avoid oil mixtures containing oil and alcohol, but I've found that it is usually possible to distill them off at atmospheric pressure
without a vacuum without losing much product (note that some things will steam distill with water in unacceptable proportions). Can you distill off
the alcohol and water first at atmospheric pressure? Or maybe salt out the water and just distill out the alcohol?
Simply evaporating them under the pump will probably work but will cause wear and tear on the pump. I would probably try condensing the alcohol vapors
even under reduced pressure - the boiling point of isopropyl alcohol really isn't that low. Also, leaving alcohol and water in your pump oil is a bad
idea; water can cause corrosion and alcohol can cause lower viscosity. Both have a vapor pressure and will lower the ultimate minimum pressure of your
pump if allowed to remain in the oil.
[Edited on 16-3-2017 by JJay]
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Tsjerk
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This works quite well with a water aspirator without a cold trap as the vapors will be immediately diluted with lots of water.
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Liamatpm
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Are you talking about a vacuum pump or a water type pump or a vacuum cleaner?
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Tsjerk
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I'm talking about a water stream type pump. A normal pump will also work but the solvent will degrade the membranes or in case of a oil pump dissolve
in the oil.
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Liamatpm
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Tsjerk I figured but I wasn't very sure.
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LD5050
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A vacuum cleaner for a lab pump?! has anyone really done this??
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Liamatpm
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I've seen some videos on highly modified vaccum cleaners. It's a waste of money, resources and time but some people do it.
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Geocachmaster
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How about Tdep before his new one
Youtube video
I use one with some success, only for filtration though. The addition of a vacuum cleaner speeds up filtration quite a bit, but the excessive noise
produced by my 1960s vacuum means I use it only on rare occasions. I'm not sure how low a pressure is actually produced, I can't imagine it's very low
(not less than 400mmhg, ethanol will boil at around 62C for reference). Probably a no go for vacuum distillation.
Soon I will buy a water aspirator, much better
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Praxichys
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Easy. Just add a bunch of table salt and the isopropanol will layer out and take the oil with it. Decant the isopropanol layer off the water/salt and
evaporate the alcohol with gentle warming.
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