Rotary Evaporators

tommy_greens · Jun 9, 2014

Thinking of picking up a rotary evaporator for vacuum distilling and reclaiming ethanol after winterization. Hydrion is making them and theirs are quite affordable.

Heres the proposed process:

1. extract in closed loop. recover butane to -10 hg with apion.
2. pour ethanol or iso into collection pot and stir until dissolved.
3. Winterize in freezer (-18 C). Filter out precipitates with buchner.
4. evaporate alcohol in rotovap untill just enough alcohol remains to keep the absolute (bho) liquid enough to pour onto parchment.
5. Pour onto parchment trays and degas in vacuum oven until a shatter consistency is reached.

Does anyone use this process?
If not, why not?

Your thoughts please.

Tommy

hairetsu · Jun 9, 2014

I wouldn't spend ANY money on a rotovap from Hydrion. Not that i have heard bad things, but buying the wrong rotovap can make for a costly and useless purchase from what i've read. I'd look into what others use as far as rotovaps go in the industry.

In my opinion, I wouldn't purchase a rotovap unless i was working with solvents with higher boiling points such as, d-limonene.

If you wanted to reclaim alcohol, i'd suggest just a simple distillation kit rather than rotovap.

while the rotovap might increase the left over terpenes in the product i don't see it being worth the price of the equipment.

I'd be much more interested in purchasing a rotovap for d-limonene extracts.

Gray Wolf · Jun 9, 2014

A rotary evaporator is definitely the fast way to remove solvent, and we are pursuing that end with our own drum design.

I haven't built one of our prototypes yet, but one of my associates built his own version of it, which actually works pretty well and certainly blows the doors off of open evaporation and eliminates the water pickup from the atmosphere, from using fans.

tommy_greens · Jun 9, 2014

Speed and quality are the two biggest goals. We have a 4 hour extraction time and that is close to continuous. There is no down time. I have a vacuum distillation kit on order but now im beginning to worry that it will not keep up with our extraction times and i'm also concerned that we will have to manually control the water bath temperature. I'm considering cancelling that order. Rotary evaporation seems to be the safest and fastest while maintaining the highest quality.
I'm curious why you warn of hydrions rotovaps if you havent used one haietsu?
Second post would have to have a little more substance for me to buy in as you dont have the reputation around here to speak for you... Like a Grey Wolf per say.

Extraction is 200g to 300g every 4 to 5 hrs. Starting at 6 am.
We will dissolve in 2000 to 3000 ml alcohol.
Will one vacuum distilation kit keep up at a temperature low enough to keep quality high?

HashoftheTitans · Jun 9, 2014

Gray Wolf said:
A rotary evaporator is definitely the fast way to remove solvent, and we are pursuing that end with our own drum design.

I haven't built one of our prototypes yet, but one of my associates built his own version of it, which actually works pretty well and certainly blows the doors off of open evaporation and eliminates the water pickup from the atmosphere, from using fans.

Do you think that using a removable PTFE bucket liner in your associates drum design would allow you to do butane evaporation to produce shatter in an easily retrievable form?

Lono · Jun 9, 2014

Roto vaps seem fun. Definitely would like one as soon as I have 2-3k to throw around.

Here is an article about the Stanley brothers. Check out what they're using:

http://america.aljazeera.com/watch/...oradofamilymakesgoodinmedicalpotbusiness.html

Lono · Jun 9, 2014

Tried to find the model they have, found the manufacturer. What do you ya'll think?

http://www.heidolphna.com/products/rotary-evaporators/product-line-overview/

Think I found it:
http://www.coleparmer.com/Product/R...are_Manual_lift_Heating_bath_115V/EW-28702-05

So affordable. Can I has?
http://www.heidolphna.com/products/rotary-evaporators/product-line-overview/

hairetsu · Jun 9, 2014

first things first, rep or not.. Grey Wolfs word > me lol i stand by that!

I just say look into it. I've done a lot of reading when i was choosing vacuum ovens, and have heard some things about Hydrion's quality. also being all made/assembled in china. Things might be different.

That being said "I" consider Hydrion, entry level equipment. i've also read/heard when it comes to purchasing a rotovap cheap ones aren't the best choice.

I could be wrong and maybe for your application it would be fine.

G.O. Joe · Jun 10, 2014

tommy_greens said:
We will dissolve in 2000 to 3000 ml alcohol.
Will one vacuum distilation kit keep up at a temperature low enough to keep quality high?

The temperature depends on the vacuum pull. The length of time depends on the size of this kit. For 3 liters and all 24/40 glass, a long time. So there's so handy rotavaps, and suction tube inlets in them.

No one wants to pay ridiculous prices, but for Buchi that's resale value, especially if you don't break the glassware. There's used Buchi for the price of new Chinese, and parts will always be available.

The big rotavap buying mistake is getting the standard size if you need the 5 liter size. That'll strip 3 in a jiffy.

Rickys bong · Jun 10, 2014

A rotavap is a good investment, but if you plan on using it for several years a used Buchi or Heidolph will guarantee being able to get replacement parts. Chances are you'll break a vapor duct and the seals will certainly wear out.

Has anyone seen a Chinese rotavap up close to assess the quality?

Things like fit of the tapered joints and quality of the glassware etc. A new condenser I bought off Ebay fit my 25 year old Buchi perfectly so it's hard not to like them...

RB

tommy_greens · Jun 10, 2014

BUMP it would really be great to hear from some one who has tried one.

Hydrion quoted me $1450 for the 5 liter.
I'm gonna see what warranty that comes with if any.

Gray Wolf · Jun 10, 2014

HashoftheTitans said:
Do you think that using a removable PTFE bucket liner in your associates drum design would allow you to do butane evaporation to produce shatter in an easily retrievable form?

It might. Right now he runs it until it gets sludgy and pours it off to finish in the vacuum oven.

tommy_greens · Jun 10, 2014

So Hydrion sais 1 year warranty on all parts except glass. They pay for shipping.
Even if it only lasts a year, it will pay for its self the first week, then i have 51 more weeks to save for a real nice quality one like a Buchi.

Vertumnus · Sep 12, 2014

It looks like the Stanley Bros are using Heidolph rotovaps.
In my experience, Heidolph has very good customer service and local reps that are very willing to help explain the different options available (at least here in the USA).
They aren't the cheapest, but the have a 3 year warranty and free PM annually. I picked up a full system w/ vac pump for about $5k

Gray Wolf · Sep 12, 2014

Vertumnus said:
It looks like the Stanley Bros are using Heidolph rotovaps.
In my experience, Heidolph has very good customer service and local reps that are very willing to help explain the different options available (at least here in the USA).
They aren't the cheapest, but the have a 3 year warranty and free PM annually. I picked up a full system w/ vac pump for about $5k

http://www.heidolphna.com/products/large-scale-evaporators/

Daub Marley · Sep 12, 2014

All the rotary evaporators I've seen use a round bottom flask with a narrow neck that makes it very hard to retrieve your extract. If you can find or mod a design that has a wide mouth opening it will be much more convenient for you. You can probably make one relatively easily. I guess you could freeze it and chip away at it or heat it enough to make it runny to pour out.

RHH · Sep 12, 2014

Rotary evaporator for...ethanol?

Overkill much? Buy a simple distillation apparatus with a liebig condenser. You can get a vacuum take-off adapter ( http://www.labdepotinc.com/Product_Details~id~319~pid~12600.aspx ) if you want to keep it low temp.

flatslabs · Sep 13, 2014

I don't think its necessarily overkill if you need a semi-automated process and are doing continuous processing, having the right (or overkill) tool for the job pays for itself quickly in a lot of cases, especially if time is your problem

A rotovap is certainly more "hands off" than a conventional distillation kit and then you still have to buy heating mantles and glassware, etc to make it work. A rotovap is more like an "appliance".

RHH · Sep 14, 2014

flatslabs said:
I don't think its necessarily overkill if you need a semi-automated process and are doing continuous processing, having the right (or overkill) tool for the job pays for itself quickly in a lot of cases, especially if time is your problem

A rotovap is certainly more "hands off" than a conventional distillation kit and then you still have to buy heating mantles and glassware, etc to make it work. A rotovap is more like an "appliance".

Hey flatslabs,

Rotovaps use heating mantles to heat the flask. You still need glassware. Ostensibly the only difference is that rotovaps rotate. The rotation increases the surface area(now we are evaporating off of all the walls, not just a flat layer in the flask).

Unfortunately, rotovaps are:
1) expensive
2) typically small volume for the amount spent.

If you are evaporating alcohol the rotation won't increase the distillation speed much at all. I know this from experience. With a rotovap you will actually spend more time filling it, disassembling it, etc. because you are not going to get a reasonably sized(>2L) rotovap for cheap.

I know it's easy to think everyone on here is a beginner...but I'm not. And I'm giving sound advice. And you're not helping by spreading misinformation and leading people to believe they need expensive equipment that isn't appropriate for the task at hand.

Chonkski · Sep 14, 2014

Are there any temp differences? Can you distill at even lower temps with the roto?

Rotary Evaporators

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