What’s up y’all? I have a Vacuubrand MD 4C NT pulling on my rotovap. I was curious if anyone out there has found or been able to create an exhaust vapor condenser for this pump that doesn’t require dry ice. I know they make a system but it seems like you have to buy the pump and condenser combo in order for it to work. I have not yet gotten an answer from Vacuubrand. Anyone have any luck with this?
I can’t speak to that particular pump but there’s mist eliminators you can buy on eBay or from edwards to fit standard kf/qf style vacuum connection fittings.
Imo you are better off condensing on the input side of the pump as that way your solvent won’t be mixed up with dirty vac pump oil. Ai makes a mechanical cold trap that used a refrigeration pump rather than dry ice
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I imagine you could use a large bubble stone and a 5gal bucket of water if you just want the liquor out of your breathing space. Change the water based on alcohol content (3-5%?!?).
Spitballing
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It’s a diaphragm pump…
@NCext if you don’t want to use dry Ice in your cold trap you can certainly purchase a mechanical cold trap. You might score one off eBay for $1000 if you’re lucky.
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I use 2 cold traps already. The issue for me is dry ice supply. It’s irregular here and the nearest maker is over 2 hours away. Their minimum for delivery is about 100x more dry ice than I need, and I don’t want to drive 2 hours and buy a bunch of dry ice that will sublimate before I use half of it. Mostly, this is about eliminating my need for dry ice and keeping the vapor out of my breathing space.
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Is speed an issue?
Temp the product sees?
If you don’t suck so hard you can condense warmer.
If temp product sees isn’t an issue you can bump temp to get your speed back up.
The link @Phytoalchemy shares to a nomograph generator here might be informative Thoughts on this chiller for a 20L rotovap? - #33 by Phytoalchemy
Allows you to investigate the bp at various Pressures.
Searching on Antoine equation will also get you this information
Edit: I prefer this calculator;
http://ddbonline.ddbst.com/AntoineCalculation/AntoineCalculationCGI.exe
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Speed is always an issue. Like money. I should have an FFE but the collapse of crude prices put the kibosh on that for the time being.
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Membranes are much cheaper. There’s a few people selling them on the forum as well.
If you did much research on ffe you should have run into yellowdog.
If you didn’t dig a thAt far, you should go find them.
You don’t actually need vacuum on a rotovap to reap the benefits of the thin film…
My research in to FFE has been limited due to the cost of the systems. It’s been a “down the road” type. I know they are fast and expensive. I know how the tech works, and that’s about it. I will look in to yellowdog. I’m assuming it’s related to FFE in a way that shouldn’t be too terribly hard to find.
Mechanical (refrigerated) could traps are the solution to your dry ice issues. Or you can get an immersion chiller and use it in your existing stainless DI trap (I don’t recommend using one with a glass trap due to thermal shock issues)
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