adk
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Where to buy a 10-20 Liter Rotary Evaporator?
Look for second hand equipment.
A standard laboratory rotary evaporator supports a 3000 mL flask at most. It is not possible to use it with larger flasks due to the weight bearing on
the conical glass joint. You can use a vacuum feed system as is shown in this video: https://www.youtube.com/watch?v=fn2T4stVb9Y
If you want 3000 mL or larger (5 L, 10 L, 20 L etc) you're going to need to go to a manufacturer such as:
Büchi Labortechnik - the very best equipment money can buy. Very commonly used in industry. Ultra reliable and very well supported by the
manufacturer (Switzerland)
Lots of second hand/used models available as they invented the rotavap several decades ago. The model you want is probably the R-220. Condensers and
feature selection dependent on boiling point and volatility/vapour pressure of compounds.
Heidolph Instruments - good value for money - German quality. I have a Heidolph laboratory scale unit and it runs well. Not sure about their larger
units but a colleague gives them the thumbs up.
Asahi Glass Plant - high quality and very large scale units from Japan. Great build quality and affordable. I have not used but they are highly
recommended.
I don't recommend buying this type of equipment from China; I have heard some horror stories about complex equipment sourced in China. You might be OK
with a basic chemical reactor but don't count on after sales support or warranty.
In addition to the rotary evaporator, you will need a vacuum source, vacuum controller, three phase power, cooling circulator and probably a fume
extraction enclosure.
FYI, if you're conducting vacuum distillation of large amounts high boiling point organic compounds (with a boiling point under vacuum that is higher
than the boiling point of water at atmospheric pressure), you wouldn't use a rotary evaporator.
You would use a heated reactor (normally glass lined stainless steel) with a high vacuum system and gas inlet tubes, overhead stirring.
Rotary evaporators are much better suited to quickly distilling solvents from reaction mixtures.
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MrHomeScientist
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First a 50L hot plate / stirrer and now a 20L rotovap? Why such a large scale? Is this for a business you are running? Just curious.
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adk
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50 L hotplate stirrer? That's the distilled and refined version of ScienceMadness. Use overhead stirring for anything over a couple of litres.
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Ozone
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Check out ALT, Biosurplus, (labx typically covers them all) and others. Here's one 20L set-up (I prefer the R-220, but they are harder to find): http://americanlaboratorytrading.com/lab-equipment-products/...
Ah, here's an R-220: http://www.labx.com/item/buchi-rotavapor-r-220-evaporator-sy...
O3
[Edited on 10-5-2017 by Ozone]
-Anyone who never made a mistake never tried anything new.
--Albert Einstein
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cabal
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I was just thinking: At this scale, wouldn't it be more economic to just build a still out of stainless steel parts? You could get that done with
about 100-200 bucks. You can get 10-20 L pressure cookers very cheap online. They usually have a valve on top to release excess pressure - screw that
off and use that hole to connect a condenser. In countries where moonshining isn't prohibited, you can buy condensers with standard fittings for about
100-150 bucks. My still even has a 1 m fractionating column on top. Adding vacuum capabilities isn't hard, either.
The way I see it, the main advantages of a rotovap are comfort and increased efficiency. But is the reduction in evaporation time and power
consumption worth the huge amounts of money you'll have to pay for a rotovap with a 20 L evaporation flask? If you plan to spend the next decades
evaporating huge amounts of liquids on a regular basis, the answer is probably yes. If you're evaporating extremely corrosive material that wouldn't
go well with a metal still, the answer is probably also yes. But in most other cases, I think building your own still could be a viable alternative.
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