Hexane through buchner safety?

Hi gang,
I’ve been lurking quite awhile and have been acquiring equipment over the last few weeks. My last open blast (experiment with @MediaBros CRY that turned out amazing) was today and am moving to a @Killa12345 closed loop that arrived today. I’ve really enjoyed reading through all the different processes to get things accomplished and am looking forward to trying some of these techniques.
I have a plan to attempt an Methanol winterization/LLE with some rough BHO that I already have. Once I’ve pulled the oil into the hexane I’d like to run it through the CRY media in a Buchner funnel just to see what happens.
My main concern is safety and fire with the hexane. Assuming there is good ventilation am I asking for trouble pulling hexane vapors through my Rocker 400 diaphram pump?
IG: PhenohuntPhotography

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I found that you don’t need a pump sometimes it just flows passively. A pump regulator would be nice to use. Or put the collection on dry ice, or even inline dry ice trap

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True that. The media won’t create any back pressure so he should be good to just pour.

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Thanks for the response. I’m sure it would flow through the CRY media. I plan on have a bit of Celite underneath. Think it would flow through Celite?
I’ll give that a shot. Never thought to just try it without the pump.

Why not just use standard water aspirator on your funnel? Then you don’t have to worry about it going into the pump.

Almost every hood I have ever used actually had a water aspiration connection right in the hood exactly for this purpose. You get a little bit of vacuum to help you out, but you are not worried about where your pump is venting cause the vent is still in the hood and there are no mechanical parts.

image

Also I 100% agree with @Apothecary36 - you probably don’t even need to pull vacuum, it will passively filter over time in the hood. So the water aspirator should be more than enough.

Good luck!

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Water aspirator would be cool for sure. Any venturi style pump would be very safe.

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I have heard you can vaccum down a canister and then use it to “hold vacuum” for such a use case. No personal experience however

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Thanks everyone. I guess I get all caught up seeing all the great gear you guys have and forget about the simple solutions. Off to buy a water aspirator.

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Yes I used to filter butane through a buchner funnel like this.

2 L buchner funnel with vacuum port
2-5 L flask
2L Pyrex measuring cup
Dry ice
Pressure vessel or vacuum chamber (bvv chamber )
Cheap vac pump

  1. Pre chill buchner funnel pyrex measuring cup and hydrocarbon tincture on dry ice for 10 min or longer
  2. Prepare filtration flask to be secure in a dry ice bath
  3. Pull a full vac on chamber and close valve to pump
  4. Mount buchner and line with a coffee filter as well as a fluted coffee filter
  5. Pour 1 Liter of hydrocarbon tincture into buchner funnel with a Pyrex measuring cup. Dont try to pour 2 L batches.
  6. Very gently pull vacuum on buchner using the vac chamber. Dont open the valve all the way. You want your vacuum to last long enough to pull everything through.
  7. Empty collection into clean mason jar
  8. Re freeze buchner as necessary.

Dont do this unless in a c1d1 environment.

Ps you can use the tincture inlet of your rotovap as a vacuum line to pull a vac on your buchner. Pull a vac on your roto with the chiller running…

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@PhenohuntPhotography We’ve tried it before to test the flow. I’d say that if you run the media in the funnel, use no less than two coffee filters to create a little back pressure. Otherwise the solvate flows too fast through the media… and that’s without a vacuum assist.

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Water apirators are really wasteful. They sell aspirate pumps with rotos but you’ll end up with hexane in the loop of that unit.

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You’re mad about wasting water? Don’t be silly. Electricity and heat are waste products too. And water in most places that goes down the drain gets immediately treated and reused.

This has been used for years. Doesn’t require any super special stuff. And won’t catch fire randomly. x.X

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I’m just a “garage” extraction guy who doesn’t have to worry about a lot of the efficiencies that many here do.

I agree with @Cassin. Water aspirator is the cheap safe way to do this. Someone else mentioned a vacuum regulator as a way to avoid boiling hexane which is a pretty good/cheap idea but will not solve the problem outright.

If you have a big tank you can pull vacuum on and then use as a reservoir is an effective method IF you keep the funnel loaded with liquid. Once air sucks through you will lose vacuum very quickly

I used a peristaltic dosing pump as my vacuum regulator once :laughing:

Don’t mind the mess

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Lol I would never have thought of that, nice kludge! How well did it work?

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Perfect :ok_hand:

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Unfortunately it’s in Singapore but at $88, this is almost cheaper than an IRV20 regulator lol. Bonus is, it’s also a peristaltic pump!

https://www.ebay.com/itm/LONGERPUMP-LONGER-PUMP-BT100-2J-WITH-YZ1515X-ROTOR-ADAPTOR/312979319778?chn=ps&norover=1&mkevt=1&mkrid=711-117182-37290-0&mkcid=2&itemid=312979319778&targetid=935065067467&device=m&mktype=pla&googleloc=9006213&campaignid=10877149879&mkgroupid=105798940543&rlsatarget=aud-622524040998:pla-935065067467&abcId=9300400&merchantid=101683249&gclid=CjwKCAiAnIT9BRAmEiwANaoE1f8dvFF_MOf3LZwwqhtJ_k9-FwEFlsHy3gsscUIvcZndMnMtCtwQ0xoC2dwQAvD_BwE&pageci=08e60554-1cef-4e5b-aaa1-07471c8db1a7

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Really…you think there is a risk of boiling hexane under a vacuum? Boiling point is like 154F. Can’t seem to find the temp of Hexane under a vacuum though.

That was my thought too, what if I just ran it through a lot of media and/or multiple times. Honestly, I’m just going to to play around with it and see what happens.