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Author: Subject: Distillation set questions
Hilski
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[*] posted on 11-10-2006 at 13:19
Distillation set questions


I plan on buying the equipment needed for doing distillations and I had a couple of questions.

I already have some non-ground glass joint equipment, including various flasks, and 2 large Liebig condensers. I know ground glass joints are better for doing distillations etc, but I would still like to be able to use the other stuff, especially the condensers, if the need arises.

I do have a few 24/40 boiling flasks, and I want to get a 24/40 Vigreux column, and if I really need it, a 24/40 Liebig. Of course I will also get all the adapters and stuff needed for thermometers, vacuum etc.

What types of things CANNOT be distilled using rubber stoppers with holes instead of ground glass equipment? Also, what is a good general size Vigreux column, and Liebig condenser to get? I probably won't be doing any huge distillations, so I don't want to get stuff that's way too big for the task, but I also don't want to buy equipment that undersized either.

Any other advice you can give before I start buying stuff will be greatly appreciated.

Thanks
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cyberzed
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[*] posted on 11-10-2006 at 13:28


I think everything will depend on the job you are going to perform. If you are looking like small distillations, then start with small equipment.
For my first equipment i had 29/32 liebig, rbf's vacuum allonge and distillation head and was sorry because in the end for a small distillation it did not seem to be that efficient.

Like i said, everything will depend on the job you will be performing, if you want to do small distillations, the start with small equipment.
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Hilski
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[*] posted on 11-10-2006 at 16:22


I think it would be safe to say that the largest thing I would ever try to distill would fit in a 1000ml flask with no problem. Although, a large majority of the stuff would probably be on a lot smaller scale, say 250ml at a time or smaller.

[Edited on 12-10-2006 by Hilski]
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Magpie
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[*] posted on 11-10-2006 at 17:49


I have an organic kit with ground glass joints which I really enjoy. It is vapor tight which is important for many experiments. There is only one place that has rubber in the kit - the thermometer adapter. The only time it has been attacked was when I made nitric acid. I have added a Teflon thermometer adapter to my lab. It will be used next time I make nitric acid.



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evil_lurker
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[*] posted on 12-10-2006 at 00:34


My personal preference it to work with stuff on the 5-10 mole scale because its a bit easier to get higher yields of purer product. A 24/40 jointed distillation setup using a 1000ml boiling flask and 500ml reciever is perfect for most situations. United Glass Tech on EBay has some very attractive and high quality complete distillation setups for $199-260 USD. They should be your first place to get glassware. I'd start out with the 2 liter flask and 1 liter flask as an option, then you can always scale down by simply purchasing a 500ml flask for around an extra $20. Don't get anything but round bottoms if you ever intend to use vacuum in the future.

Your condensor size and type should be based on the boiling point of what your trying to distill and how fast you want to run the material through it. Generally you can't have one too big, unless you have small lab table. Materials with low boiling points say below 40C and high partial vapor pressures (bromine and ether are two things that come to mind) you'll want to use a graham or double surface coil condensor at least 300mm long using ice water. Liebigs work well for everything else. A 200mm liebig will handle alcohol and most other materials boiling over 40C just fine. If I had to buy another one though it'd probably be 300mm.

For fractionating, I'd go with a 300mm vigreux to start. Should give 3-6 plates of separation depending on how fast you run it. Anything that your distilling with a boiling point of under 100C and generally the column does not need to be insulated.

The sky is the limit from thereon.
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drspastic
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[*] posted on 13-12-2006 at 03:19


Hi, this is my first post on the site so I hope I am placing it in the right place.
I am in the process of getting together a quickfit setup, my chemistry from college is now many years ago and unused (mostly).
I am finding it hard to decipher the codes for the fittings, most of the stuff I got is b19 and b14. The problem now is a graham condensor that says cx3/04 and I just got lost!
I understand b14 being 14mm etc but cx3/04 makes no sense to me.
What size cone is it and what flask do I need to go with it?
What does the b in b14 etc mean?
Sorry for placing such basic Q's here but I am stuck! Maybe someone can suggest a good site with all this basic fitting info.
Cheers to all!




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matei
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[*] posted on 13-12-2006 at 10:17


drspastic,

cx3/04 is the manufacturer's code for that particular condenser (which if it is "Quickfit" is now manufactured by Bibby Sterilin). You must look for the symbol written near the conical joint. I have attached the designation of conical joint sizes from the Bibby Sterilin Catalogue:

Attachment: Technical_information_glassware.pdf (358kB)
This file has been downloaded 14831 times

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drspastic
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thumbup.gif posted on 13-12-2006 at 11:55
thanx


cheers m8 that was just what I needed!

(I like it here)




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Biginelli
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[*] posted on 29-12-2006 at 11:45


Hilski,

*What types of things CANNOT be distilled using rubber stoppers with holes instead of ground glass equipment?*

ANY type of halogen-organics (will extract filler stuff from rubber), non-polar liquids like toluene, ligroine, hydrocarbons, etc.
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microswitch
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[*] posted on 16-1-2007 at 17:59


I see a lot of internet offerings for round bottom flasks. Why are they so popular, it seems like Erlynmeyer flasks would be easier to work with.



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pantone159
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[*] posted on 16-1-2007 at 18:22


You can't put erlenmeyer flasks under vacuum.
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Chemist514
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[*] posted on 17-1-2007 at 07:02


Quote:
Originally posted by pantone159
You can't put erlenmeyer flasks under vacuum.


Ok, fine.. but whats up with the "filter flask"? due to reduced stress from the pasing of liquid/air through the filter its ok?

you could use ground glass erlenmeyers to distill sulfuric acid at atmospheric presure or is the temp a limiting factor here? (in excess of 340 C probably)

Thanks, and all the best!
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matei
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[*] posted on 17-1-2007 at 07:36


Filter flasks are specially manufactured with thicker walls so they withstand vacuum.
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[*] posted on 17-1-2007 at 07:37


Little things that make your life a lot easier but that you may not know that you need:

1. PTFE sleeves for your standard taper joints. Using these you need no grease therefore risk no contamination of your product. You won't want to ever use joints dry as they can lock up and be hard to seperate without risk of breakage.

2. Keck or other joint clips/clamps. Various plastics or metals.

3. QD hose couplings to fit over tubulations for cooling water, suction lines etc. are a major convenience.

4. Fritted glass filtration funnels are a major improvement over conventional Buchner funnels and filter paper. You may need to experiment with different grades of frit depending on particle size.
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chemrox
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[*] posted on 18-1-2007 at 00:51
distillations and columns


For atmospheric pressures an Ehrlenmeyer flask with a 24/40 joint is nice if you have a stirring hot plate (ebay). Otherwise 250, 500 & 1000 RB's are nice. Heating mantles are a nice commodity to aquire. A vigaraux column doesn't do very good separation. The longer the better and a heating tape is nice.. anything you can do to keep the temperature on the column at the temp of the rising vapor. A partial takeoff head with a cold finger at the top helps too. Consider a settup for steam distillation. I made a steam generator from a pressure cooker and if you do that you need a water trap in the line. I'm working on a Podbielnak column. Find plans in a lab manual by Cason & Rappaport. I'll copy and post the thing one of these days. Get a cork borer and corks instead of rubber. Not really good for vacuum but better than rubber for a lot of things. The kontes chem kits alluded to above are cool. Get one if you can afford it. I found rediculously cheap pressure equalizing addition funnels at used aparatus sites and ebay.
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MadHatter
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[*] posted on 18-1-2007 at 08:37
Distillation Components


While I appreciate ground glass joints, teflon sleeving, etc., I'm currently in search of stoppers
made from Viton. Rubber, neoprene, and cork stoppers are easily attacked by acid distillations.
It appears that Viton resists most, but not all, acid attacks. I just think a "stopper" would make
a better seal for vacuum applications. If anyone out there knows where I can find these for
a reasonable price please U2U me. I have pounds of solid, 1-hole, and 2-hole rubber stoppers.
They're great for non-corrosive applications but I would dearly love to have several of
those made with Viton !




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