Sciencemadness Discussion Board

Condenser questions

DalisAndy - 1-12-2015 at 09:58

I have been reading upon condensers recently, since I want one (along with all other need distillation parts). Which condenser should someone get if they only want todo simple distillation?

szuko03 - 1-12-2015 at 10:16

Get a liebig so you dont regret not getting that one first. You can accomplish a wide range of distillations with a liebig as well as reflux. As far as the length I would say something like 300mm is good for standard stuff anything longer might be over kill and think about how long your work space is how many supports you have when considering length.

There are a lot of different condensers, maybe not A LOT but a few start with the liebig as it is the most well rounded and useful one. Just look at some of the set ups in the "prepublications" most use a liebig

Amos - 1-12-2015 at 10:21

Since most distillation setups sold as a bundle online contain a Liebig condenser, you might just want to go ahead and get a whole distillation kit; it should save you on purchasing each piece of glassware individually. I believe there's a thread on specific kits to buy somewhere on the site, search for it. You'd want to look on Aliexpress and eBay for both the kit or individual pieces, and 24/40 ground glass is probably the best way to go.

If you're looking for a condenser by itself, this is the one I just bought: http://www.ebay.com/itm/300mm-24-40-Glass-Liebig-Condenser-L...

szuko03 - 1-12-2015 at 10:24

I second the opinion of buying a kit if you are looking for the fast and easy method. We are in a great age of cheap distillation kits directly from china. Definitely look for 24/40 as that is what is common in the US, so when you want to upgrade what you have its easy to find compatible items.

I went the long drawn out way of finding name brand glass in the auction section or people putting up name brand stuff at decent prices. I managed to get a full chemglass/pyrex lab for fractions of the actual cost and if i gently use it it should retain most of its value... but i would prefer you didnt bid on the items i want so dont listen to me ;)

But i now no longer fumble over the names of anything because when you spend a week researching a single piece of lab glass you dont forget the name. That was another reason why i did it i am not in a rush to get started and would rather have a good lab with good equipment before stocking chemical inventory. Just a different way of looking at it.

[Edited on 1-12-2015 by szuko03]

DalisAndy - 1-12-2015 at 11:13

Any recommendations on kits? I'm having a little bit of a hard time finding any

Detonationology - 1-12-2015 at 11:44

Make sure to buy 3.3 borosilicate glass (thermal coefficient 3.3 x 10-6/K) if you want it to last. I don't trust lime glass after having a round bottom explode all over me from thermal shock. Scared the hell out of me too.

szuko03 - 1-12-2015 at 12:35

Quote: Originally posted by Detonationology  
Make sure to buy 3.3 borosilicate glass (thermal coefficient 3.3 x 10-6/K) if you want it to last. I don't trust lime glass after having a round bottom explode all over me from thermal shock. Scared the hell out of me too.


Stories like that made me spend the extra money on "chemglass" brand round bottom flasks. Over kill perhaps but when it comes to the heating mantel and boiling flask i would rather spend the money and be safe.

Dr.Bob - 2-12-2015 at 04:49

I still have a few condensers left in 24/40, plus I have a few other distillation parts left, so if you wanted to build a distillation kit, I could put a 24/40 setup together for about $100, all used but US made borosilicate glass. I just got a few more pieces to allow me to complete some distillation kits in both 14/20 and 24/40.

Bob

The Volatile Chemist - 2-12-2015 at 12:47

So...Grahm condensers are bad for reflux...? They seem like they would work well (I don't own one) but from what I've heard they don't? Or is it just the tilted ones...? Sorry if this is a silly question.

DalisAndy - 2-12-2015 at 20:22

Ok which one of these would you guys/gentlemen recommend for the average home chemist?
http://www.laboyglass.com/chemistry-distilling-set-24-40.htm...
http://www.laboyglass.com/advanced-chemistry-lab-glassware-k...

[Edited on 3-12-2015 by DalisAndy]

j_sum1 - 2-12-2015 at 21:41

@Dalisandy
You have picked two very different kits. The first is really only suitable if you are doing one thing at a time. You will distill ok and then you will have to clean all your glassware before you do something different.

A couple of things to consider.

1. before you start you need to work out as much as possible what you intend to do. Are you just distilling or will you be performing syntheses? Do you need to reflux? If you are doing reactions you need to consider inputs for your reaction flask, ie, multiple necks.

2. You need to think how you will be doing your heating. Perhaps the easiest and cheapest is a hot air gun of the kind used to remove paint. I ended up shelling out for a heating mantle with stirrer. Hot plate and water bath or variants are another option.

3. You will break something. Guaranteed. It is part of building up experience. Something cheap is probably better for your first hit. That said, you will not regret having something quality. For a small kit, if you break something you are completely out of action until you get a replacement. Worthwhile remembering.

4. A separate thermometer adapter is a good idea. It can be used for a variety of things -- especially if you have some 6mm glass tubing. You can also remove it easily and add things to your flask. Or for some applications you can replace it with a stopper.

5. It is hard to know, but consider what kind of condensing you will need. A liebig is very versatile. But you might want a fractionating column (vigreux) or something with better heat transfer (Graham or Friedrichs)


Probably more thoughts but I have to go.
Check out the guy I advertised at synthsource (link below) I got good glass from him.

DalisAndy - 3-12-2015 at 10:03

@j_sum1
I only really need it for basic distalltion, like for lacquer separation or making borate esters. I'm not going for hardcore chemistry. The main thing I may use it for at this time is water removal from Cheveul's salt. I have a heat source already, a basic alcohol lamp. Not the best but it works

[Edited on 3-12-2015 by DalisAndy]

MrHomeScientist - 3-12-2015 at 10:19

If you're just getting rid of water, distillation seems somewhat unnecessary. Surely you don't need to recover the water?

DalisAndy - 3-12-2015 at 17:02

Quote: Originally posted by MrHomeScientist  
If you're just getting rid of water, distillation seems somewhat unnecessary. Surely you don't need to recover the water?

No but like I had stated in my other post on the wondrous salt. The "sulfur that was produced, If it does that again, I'm hoping to capture it.

The Volatile Chemist - 12-12-2015 at 14:59

Quote: Originally posted by The Volatile Chemist  
So...Graham condensers are bad for reflux...? They seem like they would work well (I don't own one) but from what I've heard they don't? Or is it just the tilted ones...? Sorry if this is a silly question.

Just being an arse and quoting myself because I'd love an answer...
I may be getting a set of 24/40 glass for Christmas (would you believe it), and my parents want to get the cheaper set from HST. It doesn't have a liebig, which I can easily get later. But can I reflux with a graham?

Amos - 12-12-2015 at 16:57

Quote: Originally posted by The Volatile Chemist  
Quote: Originally posted by The Volatile Chemist  
So...Graham condensers are bad for reflux...? They seem like they would work well (I don't own one) but from what I've heard they don't? Or is it just the tilted ones...? Sorry if this is a silly question.

Just being an arse and quoting myself because I'd love an answer...
I may be getting a set of 24/40 glass for Christmas (would you believe it), and my parents want to get the cheaper set from HST. It doesn't have a liebig, which I can easily get later. But can I reflux with a graham?


The issue with trying to reflux using a Graham condenser is that once some vapor condenses up in the spiral part of the inner tube, it remains liquid and just gets pushed up by the pressure of the vapor below. The inner tube itself is too narrow for the liquid to displace the gas below and fall back into the reaction vessel, so the result is a continual rise in the liquid inside the condenser until it's practically bubbling out the top. In desperate times, though, I have found that putting a Vigreux column between the reaction flask and a Graham condenser works just fine if you don't heat too aggressively.

The Volatile Chemist - 14-12-2015 at 15:07

Makes sense. Will HCl react much with rubber stoppers? I guess I'll have to use non-ground glass if the graham condenser acts up too much.