smaerd
International Hazard
Posts: 1262
Registered: 23-1-2010
Member Is Offline
Mood: hmm...
|
|
Picking the right condenser?
Hello again sci madness  .
Well I'm obviously quite a noob as I've stated in just about every post now. Being a noob I need some helpful suggestions, this time about condensers.
So from what I've gathered is there are Liebig condensers and Graham condensers. These come in a variance of lengths(200mm to 500mm).
I've only personally worked with a liebig condenser before in the lab at school. I used it for distillation, which was cool.
So I know a liebig can distill and a graham can reflux. Is it possible to use a liebig to reflux, or is that not safe? If not can a graham be used for
simple distillation?
Ideally I'd like to have a condenser that can handle small volume liquid distillation(250ml rbf only filled to 125ml), and small volume reflux(250ml
rbf limitation again).
Any suggestion on lengths(mm) or which type of condenser might suit these needs best? If I'm missing something here, feel free to let me know  .
edit - Also what is the name for those sink faucet to tygon tubing adapters? 
Thanks again!
[Edited on 10-3-2010 by smaerd]
|
|
|
DJF90
International Hazard
Posts: 2266
Registered: 15-12-2007
Location: At the bench
Member Is Offline
Mood: No Mood
|
|
There are in fact, many more condenser types than two. However I'll keep this brief as I'm sure you're capable of finding out about the others
yourself.
The liebig condenser is your "all round" condenser. It can handle most tasks you can throw at it, whether it be reflux or distillation.
The graham condenser comes in two varieties itself; coolant around the coil, and coolant through the coil. Now I cant remember much about the former,
do I'll discuss the latter. This condenser style typically has more surface area than the Liebig, per unit length. As far as I am aware, it is not bad
at either mode of use, but with distillation you supposedly get "creep" around the cooling coil, leading to incomplete condensation. I'm not sure how
severe this is, but it can't be that bad because Buchi use a similar style in their Rotovap condensers. And of course the graham condesner is
perfectly at home in reflux mode.
Other flavours you might like to look at are:
Jacketed coil
Davies double surface
Double coil
Freidrichs
Air
Ether
Typical lengths will vary with joint size, but for a B24 joint you will typically find 360mm adequate for a Liebig. 200mm may be fine for some/most
applications. For more extreme cooling 450mm and 530mm are generally available options.
For a graham, I've seen 200mm and 400mm available, and maybe one in between.
I hope this was helpful to some degree.
[Edited on 10-3-2010 by DJF90]
|
|
|
Skyjumper
Hazard to Self
Posts: 93
Registered: 1-3-2010
Location: Assachusetts
Member Is Offline
Mood: Refluxing
|
|
I wish I had a condensor that could be used as a reflux :3 My lab only has this old, old condensor (rubber stoppers hold the center tube inside the
water jacket!) and from the looks of it I can't seem to figure out how to set it up as a reflux (without having a lot of leaks around the rbf to
reflux connection)
|
|
|
mr.crow
National Hazard
Posts: 884
Registered: 9-9-2009
Location: Canada
Member Is Offline
Mood: 0xFF
|
|
I would recommend a small condenser (150mm) with a built in distillation head. This is good for small volumes.
Then a 300mm Liebig or West for large distillation or reflux.
There are a variety of reflux condensers available with a coil inside. There are a lot more expensive. You can use them for volatile solvents like
ether.
Everything can be 24/40 BTW
Double, double toil and trouble; Fire burn, and caldron bubble
|
|
|
Skyjumper
Hazard to Self
Posts: 93
Registered: 1-3-2010
Location: Assachusetts
Member Is Offline
Mood: Refluxing
|
|
http://unitednuclear.com/index.php?main_page=product_info&am... 40., good all around condenser.
Remember water goes in on the bottom inlet, out at the top!
|
|
|
rrkss
Hazard to Others
Posts: 193
Registered: 18-12-2009
Member Is Offline
Mood: No Mood
|
|
Personally I use a 200 mm West (Liebig with a smaller jacket) for most of my work whether that is distillation or reflux. Just get yourself one with
standardized joints and you are good to go. I like 24/40 and 19/22 joints since I don't do too much larger scale work.
|
|
|
smaerd
International Hazard
Posts: 1262
Registered: 23-1-2010
Member Is Offline
Mood: hmm...
|
|
Thanks for all the suggestions. SkyJumper I appreciate you looking into this for me however I think I'd want a ground glass condenser.
I'm going to be performing hydrodistillation primarily for aromatics/essential oils. So far here's some plants I will be distilling: rosemary, mint,
limeonene, lavender, any other fun suggestions?
|
|
|
DJF90
International Hazard
Posts: 2266
Registered: 15-12-2007
Location: At the bench
Member Is Offline
Mood: No Mood
|
|
I didn't know there was a plant called limeonene; surely you mean you're steam distilling limonene from orange peel?
|
|
|
smaerd
International Hazard
Posts: 1262
Registered: 23-1-2010
Member Is Offline
Mood: hmm...
|
|
Yes yes yes, sorry lol!
Orange terpenes, weeee. I guess it can be used a solvent, a supplement, a degreaser/cleaner, etc. Figure why let those orange peels rot?
|
|
|
bbartlog
International Hazard
Posts: 1139
Registered: 27-8-2009
Location: Unmoored in time
Member Is Offline
Mood: No Mood
|
|
Unless you have industrial quantities of orange peel (or lemon peel) you won't get enough limonene to use as a solvent or cleaner. It's a relatively
abundant essential oil (1% of the peel) but you'll still be looking at quantities on the order of a gram, if you're just using surplus peels from
household consumption.
|
|
|
agorot
Hazard to Self
Posts: 73
Registered: 25-1-2010
Location: too fed-o-phobic to say :D
Member Is Offline
Mood: like an activated complex
|
|
I have a 500 mm graham condenser that I use a lot among others, but the only problem I have with that one is that sometimes it is difficult for the
liquid to actually get through the system. What happens is that the liquid gets pushed through the condenser until eventually the pressure on the
boiling flask side cannot be increased farther by use of temperature and that pressure equals the pressure on the coolant side of the system so
basically condensed fluid flow comes to a standstill. Even with a vacuum pump on the system a point is reached where I have to let air into the
boiling flask side of the system. It can be quite frustrating, so I can only distill small quantities of things at a time with that particular
condenser.
|
|
|
bbartlog
International Hazard
Posts: 1139
Registered: 27-8-2009
Location: Unmoored in time
Member Is Offline
Mood: No Mood
|
|
Yes, that's a good point. Sometimes you really want a short path condenser just because the heat losses are too hard to overcome otherwise. I have a
300mm Hempel column and even though it has no active cooling (no circulating liquid) it can still be hard to drive things through it with an oil bath
(and direct flame can scorch stuff). Still if he's mainly doing steam distillation I don't know that that is such a concern.
|
|
|
DJF90
International Hazard
Posts: 2266
Registered: 15-12-2007
Location: At the bench
Member Is Offline
Mood: No Mood
|
|
I did a steam distillation of a quinoline the other day, and that was difficult with just the drysyn mantle (T=170*C by thermostat); I needed to use a
heat gun to drive the vapour through the stillhead and into the condenser.
|
|
|
smaerd
International Hazard
Posts: 1262
Registered: 23-1-2010
Member Is Offline
Mood: hmm...
|
|
So would a 300mm liebig be okay for steam distillation in a 250ml flask(250 limit because of my glas-col)? Would this also be sufficient for a 250ml
flask for reflux?
|
|
|
rrkss
Hazard to Others
Posts: 193
Registered: 18-12-2009
Member Is Offline
Mood: No Mood
|
|
300 mm liebeg is more than enough for those tasks as long as you have a constant source of cool water circulating through it. In fact I use a 200 mm
for most of the things you mention so 300 mm will be more than enough for everything except for maybe ether synthesis.
|
|
|
HammerOfLight
Harmless
Posts: 18
Registered: 9-8-2007
Location: Clear Lake City, TX
Member Is Offline
Mood: ZeN
|
|
I have the following;
Graham Condenser
Liebig Condenser
Packed Collumn
Vigreux Column
Allihn Condenser
riedrichs condenser
I like to have all my basses covered. The other item I have involves small hollow glass balls between a reverse version of the allihn design, the act
like a bubeller cap system only simpler.
-Bad people are punished by societies law, good people are punished by Murphy\'s law.
|
|
|
DJF90
International Hazard
Posts: 2266
Registered: 15-12-2007
Location: At the bench
Member Is Offline
Mood: No Mood
|
|
For someone who likes all their bases covered, I'm suprised by the lack of an air condenser... Nice collection though!
|
|
|
1281371269
Hazard to Others
Posts: 312
Registered: 15-5-2009
Member Is Offline
|
|
Yes I like to have my bases covered too, I never leave the lid off the sodium hydroxide.
|
|
|
smaerd
International Hazard
Posts: 1262
Registered: 23-1-2010
Member Is Offline
Mood: hmm...
|
|
How do you get it out then ?
|
|
|
![[*]](images/xpblue/default_icon.gif){kind=icon}
